Download Stage 2 Chemistry Intended Student Learning 2014

Skills
The ways in which chemistry investigation skills are expressed are set out in the following
table on intended student learning.
Key Ideas
Students should know and understand the following:
Intended Student Learning
Students should provide evidence that they are able to
do the following:
Purposes of Investigations
Investigations and experiments have a clearly defined
purpose.
Investigations are based on existing information or issues.
Before searching for information it is necessary to have a
clear idea of the information required, the level of detail
needed, and the appropriate facilities for extracting the
information.
Before undertaking an information search it is necessary
to be familiar with search techniques, the way in which the
information is structured, and the means of retrieving the
information.
State the purpose of the investigation or experiment.
For a given topic, state the key ideas or issues relevant
to the information required, and identify the type of
resource that might provide the information.
Identify key search words and phrases for a given
topic.
Use an information source (e.g. library catalogue, CDROM, or the Internet) to obtain information about a
topic.
Questions and Hypotheses
Investigable questions guide investigations on chemistry
issues.
Formulate a question for an investigation based on a
chemistry issue.
Investigations are often designed to explore questions
and to develop possible solutions to those questions.
Suggest possible investigations to test the question.
Experiments may be used to test hypotheses.
State a testable hypothesis, where appropriate.
Designing Investigations
Design
Scientific inquiry involves designing procedures, including
investigations based on the scientific method or
observations made in the field, to investigate questions.
Designing an investigation involves identifying:
 what needs to be observed
 the measurements that need to be taken
 the techniques that need to be used
 the apparatus or measuring instruments needed.
Design procedures to investigate posed questions or
hypotheses.
Every step in a practical or issues investigation serves a
purpose.
Describe the steps of an investigation.
Design and carry out investigations to explore a
chemistry issue.
Design and carry out experiments, using the scientific
method.
Record and analyse observations.
Draw or interpret diagrams of the apparatus used in an
experiment.
Variables
Many practical investigations involve deliberately
changing one quantity and determining the effect on
another quantity. These quantities are referred to as
‘variables’.
Identify the variables in a practical investigation.
The quantity being deliberately changed is called the
‘independent variable’. The quantity that changes as a
result, and is measured, is called the ‘dependent variable’.
Classify appropriate variables in a practical
investigation as independent or dependent.
Other variables are held constant, if possible, throughout
a practical investigation.
Identify any variables that are deliberately held
constant throughout a practical investigation.
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Stage 2 Chemistry 2014
Key Ideas
Students should know and understand the following:
Intended Student Learning
Students should provide evidence that they are able to
do the following:
Conducting Investigations
Procedures
Practical investigations require a particular set of actions
to be carried out in a well-defined order.
Follow instructions accurately and safely.
Appropriate apparatus is selected to undertake:
 measurement of mass, volume, temperature, and pH
 volumetric analysis
 construction of electrochemical cells
 preparation of simple organic compounds.
Select appropriate apparatus for the measurement of
mass, volume, temperature, and pH.
Prepare standard solutions, carry out dilutions, and
undertake titrations.
Construct galvanic and electrochemical cells.
Prepare organic compounds, using distillation, reflux,
and liquid–liquid extraction.
Safety and Ethics
Ethical practices must be followed when conducting
investigations.
Maintain confidentiality, report accurately, and
acknowledge the work of other people.
Safety must be considered when conducting
investigations.
Recognise hazards and work safely during a practical
investigation.
Many investigations involve the collaborative efforts of a
team.
Negotiate procedures with the other members of a
team. Define the role of each member.
Members of a team work together.
Perform the role of a team member.
Errors in Measurements
Measurements are affected by random and/or systematic
errors.
Identify sources of errors and uncertainty that may
occur in a practical investigation.
Random errors are present when there is scatter in the
measured values. Systematic errors are present when
measured values differ consistently from the true value.
Distinguish between random and systematic errors.
Where applicable, increasing the number of samples
minimises the effects of random errors and improves the
reliability of the data.
Explain the importance of increasing the number of
samples in a practical investigation.
Systematic errors can be identified and results verified by
repeating an experiment using an alternative source of
equipment and materials.
Explain the importance of repeating a practical
investigation where feasible.
Precision, Reliability, and Accuracy
The reliability/precision of data collection is related to the
reproducibility of the measurements.
Where possible, collect data using measurements that
can be reproduced consistently.
Measurements are more reliable/precise when there is
less scatter in the results.
Determine which of two or more measuring instruments
or sets of measurements is most reliable/precise.
Reliability/precision depends on the extent to which
random errors are minimised.
Use averages or graphing as a means of detecting or
minimising the effects of random errors.
The accuracy of an experimental value indicates how
close the result is to the true value and depends on the
extent to which systematic errors are minimised.
State which result of two or more experiments is most
accurate, given the true value.
The resolution of a measuring instrument is the smallest
increment measurable by the measuring instrument.
Select an instrument of appropriate resolution for a
measurement.
The number of significant figures for a measurement is
determined by the reproducibility of the measurement and
the resolution of the measuring instrument.
Record and use measurements to an appropriate
number of significant figures.
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Key Ideas
Students should know and understand the following:
Intended Student Learning
Students should provide evidence that they are able to
do the following:
Information and Data
Valid conclusions depend on gathering appropriate
evidence.
In investigations, make and record careful and honest
observations and measurements.
Practical investigations involve observations, which may
be quantitative or qualitative.
Distinguish between qualitative and quantitative
evidence.
Data can be more easily interpreted if presented in a wellstructured table.
Present data in an appropriate tabular form. Include a
title, column headings showing the quantities measured
and the units used, and the values observed or
researched.
Graphs are a useful way of displaying some forms of data.
When a graph is plotted, the independent variable (or a
quantity derived from it) is plotted horizontally and the
dependent variable (or a quantity derived from it) is
plotted vertically.
Plot a graph of dependent variable versus independent
variable. Include a title, labelled axes, and appropriate
scales and units.
A line of best fit can show relationships between variables
in an experiment.
Draw a line of best fit through a series of points on a
graph such that the plotted points are scattered evenly
above and below the line of best fit.
Understanding of a topic, issue, or question is enhanced,
using information from different sources.
Obtain information from different sources.
Evidence obtained should be critically examined for
accuracy and its suitability for the purpose for which it was
sought.
Evaluate evidence for bias, credibility, accuracy, and
suitability.
The source of information must be recorded so that the
information is accessible to others.
List the sources of information, using an appropriate
format.
Limit investigations to a manageable size and identify
available sources of relevant information.
Interpretation and Evaluation
Careful observation in a practical investigation is essential
for analysis and for comparison with other experiments.
Describe a pattern observed in the results of an
experiment.
The scatter of data points above and below the line of
best fit is probably due to random errors.
Using the scatter in the graphs of data from similar
investigations, compare the random errors.
Subsequent investigations can be improved by the critical
evaluation of the procedure and results.
Analyse and evaluate information from a series of
observations or an investigation, and suggest
improvements or indicate the additional information
needed.
A conclusion should be written at the end of each
investigation.
Write a conclusion that is based on the results of an
investigation and related to the question posed and the
purpose of, or the hypothesis for, the investigation.
Alternative Views
The evidence collected through investigations may be
interpreted in a variety of ways.
Describe a range of alternative interpretations or points
of view based on evidence, and state reasons for the
selection of the preferred interpretation.
Arguments can be presented for and against an issue on
the basis of information selected from different sources.
Construct for-and-against arguments on an issue,
based on information gathered from different credible
sources.
Personal views must be substantiated by the evidence
collected through an investigation.
Present a justification of, or evidence for, a personal
view.
Communication
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Key Ideas
Intended Student Learning
Students should know and understand the following:
Students should provide evidence that they are able to
do the following:
Communication in chemistry uses specific terminology,
conventions, and symbols.
Use chemistry terminology, conventions, and symbols
that are appropriate for the purpose of the
communication.
Chemical reactions can often be described by means of a
chemical equation.
Write appropriate chemical equations.
Communication for different audiences requires the use of
a format suitable for the purpose.
Select the appropriate format for a particular audience.
All communication needs to be well structured, well
organised, and clearly presented.
Present communications (oral, written, and multimedia)
clearly and logically, using chemistry concepts
appropriate for the audience.
Written reports should state what was done and why, the
results, the analysis and interpretation of the results, and
the conclusions drawn from the results. Sufficient
information should be included to enable the procedure to
be repeated by others.
Write a report of an investigation that includes a
description of its purpose and experimental procedure
(if designed by the student), results, analysis,
interpretation, and conclusions.
Multimedia presentations use minimal language and a
variety of graphics to present information.
Use concise language and graphics to present
information.
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CONTENT
Stage 2 Chemistry is a 20-credit subject in which the topics are prescribed.
The subject is organised so that each intended student learning is related to a key idea or
concept. Within the study of these chemical ideas and concepts, students develop their
chemistry investigation skills through practical investigations and other learning activities.
Topics and Subtopics
Topic 1: Elemental and Environmental Chemistry
1.1
1.2
1.3
1.4
1.5
1.6
The Periodic Table
Cycles in Nature
The Greenhouse Effect
Acid Rain
Photochemical Smog
Water Treatment
Topic 2: Analytical Techniques
2.1
2.2
2.3
Volumetric Analysis
Chromatography
Atomic Spectroscopy
Topic 3: Using and Controlling Reactions
3.1
3.2
3.3
3.4
3.5
3.6
3.7
Measuring Energy Changes
Fuels
Electrochemistry
Rate of Reaction
Chemical Equilibrium
Chemical Industry
Metal Production
Topic 4: Organic and Biological Chemistry
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
Systematic Nomenclature
Physical Properties
Alcohols
Aldehydes and Ketones
Carboxylic Acids
Amines
Esters
Amides
Proteins
Triglycerides
Carbohydrates
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Topic 5: Materials
5.1
5.2
5.3
Polymers
Silicates
Cleaning Agents
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Topic 1: Elemental and Environmental Chemistry
This topic deals with some of the underlying principles of chemistry (‘elemental chemistry’) and then considers the
chemistry of the environment. The elemental chemistry component of the topic focuses on the periodic table and
the concept of electronegativity; together these underlie most of the other topics in this subject outline. The
environmental chemistry component focuses on a small number of inorganic molecular substances and their
impacts on the environment.
When the chemical elements are arranged in a periodic table, similarities and trends in properties become
apparent. This topic examines the properties of compounds and elements; these properties can be explained in
terms of the electronegativities of the elements and their positions in the periodic table.
In the last hundred years, concern about the effects of humans on the environment has extended from the local to
the global scale. Students are often exposed to environmental issues, sometimes in emotive ways. In this topic
students are exposed to factual information and consider the causes of and solutions to environmental problems.
1.1
The Periodic Table
Key Ideas
Intended Student Learning
The arrangement of electrons in any atom can be described
in terms of shells and subshells.
Write, using subshell notation, the electron
configuration of an atom or monatomic ion of any of
the first thirty-eight elements in the periodic table.
The position of an element in the periodic table reflects its
electron configuration.
Identify the s, p, d, and f block elements in the periodic
table.
The periodic table is the unifying framework for the study of
the chemical elements and their compounds. Elements within
each group of the periodic table have similar chemical
properties that can be explained in terms of their similar
outer-shell electron configurations.
Predict the following properties of the s and p block
elements of any of the first thirty-eight elements in the
periodic table:
 metal, metalloid, or non-metal nature of the element
 charge of the monatomic ions
 likely oxidation number(s) of the element in its
compounds (including octet expansion for
phosphorus, sulfur, and chlorine).
The electronegativities of non-metallic atoms are higher than
those of metals; non-metallic atoms tend to gain electrons in
chemical reactions.
Find regions in the periodic table with elements of
high, intermediate, and low electronegativity.
The trend from metallic to non-metallic behaviour across a
period is related to the increase in electronegativity. These
trends are reflected in changes in the acidic/basic character
of the oxides.
Predict the acidic/basic character of the oxides of an
element from the position of the element in the periodic
table.
The oxides of non-metals are acidic. Their acidic character
can be displayed by reaction with hydroxide ions to produce
an oxyanion and, in most cases, by reaction with water to
produce an oxyacid.
Write equations for the reactions of oxides of nonmetals such as SiO2, CO2, SO2, SO3, and P4O10 with
hydroxide ions and with water, where a reaction
occurs.
The oxides of metals are basic. Their basic character can be
displayed by reaction with an acid to produce a cation and, in
some cases, by reaction with water to produce OH in
solution.
Write equations for the reactions of oxides of metals
such as MgO, Na2O, CuO, and Fe2O3 with acids and
with water, where a reaction occurs.
Metalloids form amphoteric oxides. Amphoteric oxides can
display basic character by reaction with hydrogen ions and
acidic character by reaction with hydroxide ions.
Write equations for the reactions of amphoteric oxides
such as Al2O3 and ZnO with hydrogen ions or
hydroxide ions.
Small molecules are formed from elements in a small section
of the periodic table. Small molecules are those either of nonmetallic elements or of compounds of non-metallic elements.
Predict whether or not a compound or element is likely
to be molecular, given its properties, name, elemental
composition, or formula.
Atoms in a molecule are bound strongly to each other by
covalent bonds. Molecules interact weakly with each other.
Compare the strengths of covalent bonds with the
strengths of secondary interactions.
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Key Ideas
1.2
The strengths of secondary interactions between non-polar
molecules depend on their molar mass.
Explain the higher melting points and boiling points of
substances of large molar mass.
The shape of molecules can be explained and predicted by
repulsion between pairs of bonding and non-bonding
electrons.
Draw diagrams showing covalent bonds, non-bonding
pairs, and shapes for three-element molecules and
two-element ions containing no more than five atoms.
Examples that involve valence shell octet expansion
are limited to PO43 tetrahedra, SO2 , and SO3.
The polarity of a molecule results from the polar character of
the bonds and their spatial arrangement.
Predict whether or not a molecule is polar, given its
spatial arrangement.
The strengths of secondary interactions between molecules
of similar molar mass depend on the polarity of the
molecules.
Explain the higher melting points and boiling points of
polar substances compared with those of non-polar
substances of similar molar mass.
Molecules containing N–H or O–H groups can form hydrogen
bonds to N or O atoms in other molecules.
Describe, with the aid of diagrams, hydrogen bonding
between molecules.
Cycles in Nature
Key Ideas
1.3
Intended Student Learning
The presence (aerobic conditions) or absence (anaerobic
conditions) of oxygen affects the products of the
decomposition of the organic compounds derived from
living organisms.
State, for aerobic and anaerobic conditions, the
products of the decomposition of organic matter
containing carbon, nitrogen, phosphorus, or sulfur.
Photosynthesis and respiration are important processes in
the cycles of carbon and oxygen.
Describe and write equations for the processes of
photosynthesis and aerobic respiration involving
glucose.
Nitrogen may be converted into compounds by biological
processes such as fixation or by reaction with oxygen
during lightning discharges and at high temperatures such
as those which occur in engines and furnaces.
Describe and write equations for the formation of
oxides of nitrogen by the reaction of nitrogen and
oxygen at high temperatures.
Nitrogen compounds are important in the chemistry of life
processes.
Describe how the nitrogen cycle operates by natural
processes (e.g. lightning, nitrogen-fixing bacteria, and
decay) and industrial processes (e.g. fertiliser
manufacture and combustion engines).
Plants require substantial amounts of nitrogen and
phosphorus, which they obtain from the soil.
Explain why fertilisers need to contain nutrients in
soluble form.
The Greenhouse Effect
Key Ideas
1.4
Intended Student Learning
Intended Student Learning
Some gases in the atmosphere, called ‘greenhouse gases’,
serve as insulation to maintain the temperature of the
Earth’s atmosphere. This is known as the ‘natural
greenhouse effect’.
Describe the action of the common greenhouse
gases, carbon dioxide and methane, that serve to
maintain a steady temperature in the Earth’s
atmosphere.
Human activity that affects the concentration of
greenhouse gases has the potential to disrupt the thermal
balance of the atmosphere. This is known as the
‘enhanced greenhouse effect’.
Explain the enhanced greenhouse effect and its
potential consequences for the environment.
Acid Rain
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Key Ideas
1.5
Intended Student Learning
pH is a measure of the concentration of hydrogen ions: i.e.
pH   log [H+].
Calculate the concentration of H+ and OH of solutions,
given their pH, and vice versa.
Rain containing dissolved carbon dioxide is acidic.
Write equations to show how carbon dioxide produces
acidic rain.
Rainfall with a pH of less than 5.6, known as ‘acid rain’, is
formed when oxides of nitrogen and sulfur dissolve in water
in the atmosphere.
Describe and write equations for the formation of acid
rain.
Acid rain has harmful environmental effects.
Describe the environmental effects of acid rain,
including its action on metals and carbonates (with
equations) and on the mobilisation of toxic cations such
as aluminium.
The low pH of acid rain is due to the presence of sulfuric
and nitric acids.
Calculate the pH of solutions of strong bases and strong
monoprotic acids.
Photochemical Smog
Key Ideas
1.6
Intended Student Learning
Nitrogen oxides are formed in high-temperature engines
and furnaces.
Write equations for the formation of nitrogen oxides NO
and NO2.
Nitrogen oxides lead to the formation of ozone in the
troposphere.
Describe and write equations showing the role of
nitrogen oxides in the formation of ozone in the
troposphere.
Nitrogen oxides and ozone in the troposphere are
pollutants.
Explain the terms ‘primary pollutants’ and ‘secondary
pollutants’ with reference to the harmful effects of
nitrogen oxides and ozone in the troposphere.
It is possible to reduce the quantities of nitrogen oxides
generated by cars.
Describe how catalytic converters reduce the quantities
of nitrogen oxides generated by cars.
Water Treatment
Key Ideas
Intended Student Learning
Suspended matter is removed from water by flocculation
followed by sedimentation or filtration.
Describe the use of aluminium ions in the removal
of suspended matter from water.
Hypochlorous acid, chlorine, and hypochlorites are used for
water purification.
State that hypochlorous acid, chlorine, and
hypochlorites kill bacteria by their oxidising action.
Chlorine is used for water purification.
Explain the effect of pH on the equilibrium between
chlorine, water, and hydrochloric acid and
hypochlorous acid.
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Topic 2: Analytical Techniques
Chemists perform a wide variety of monitoring roles, including analysing for drug residues and measuring the
concentrations of pollutants such as pesticides in the environment. Chemists are also employed to analyse
materials used in or produced by many branches of industry, including pharmaceuticals, polymers, metal
production, and food preparation. In this topic students consider some of the more common means of analysis and
undertake practical activities in measurement.
2.1
Volumetric Analysis
Key Ideas
Intended Student Learning
Concentrations of solutes in solutions can be described by using a
number of standard conventions.
Convert concentrations from one unit to another
(e.g. mol L1, g L1, %w/v, ppm, and ppb).
Knowledge of the mole ratios of reactants can be used in
quantitative calculations.
Perform stoichiometric calculations when given the
reaction equation and the necessary data.
A titration can be used to determine the reacting volumes of two
solutions.
Describe the correct use of a volumetric flask, a
pipette, and a burette.
Analysis of a variety of chemicals depends on an understanding
of quantitative aspects of chemical reactions, including acid–base
and redox reactions.
Describe and explain the procedure involved in
carrying out a titration, particularly rinsing glassware
and determining the end-point.
A titration can be used to determine the concentration of a
solution of a reactant in a chemical reaction.
Determine the concentration of a solution of a reactant
in a chemical reaction by using the results of a titration.
2.2
Chromatography
Key Ideas
Intended Student Learning
Adsorption chromatography involves the use of a stationary
phase and a mobile phase to separate the components of a
mixture.
Identify the stationary and mobile phases in an
adsorption chromatography process.
The strength of attraction between two substances depends on
their relative polarities.
Predict the relative strengths of attraction of
components for the stationary phase and the mobile
phase on the basis of their polarities.
The rate of movement of any component along a stationary
phase is determined by the structure or relative polarity of the
component and the relative polarities of the stationary phase and
the mobile phase.
Predict the relative rates of movement of components
along a stationary phase, given the structural formulae
or relative polarities of the components and the two
phases.
The rate of movement of a component along a stationary phase
is compared with a known standard in order to identify the
component.
Describe and apply RF values and retention times in
the identification of components in a mixture.
2.3
Atomic Spectroscopy
Key Ideas
Intended Student Learning
Electrons move to a higher or lower energy level when atoms
or ions absorb or emit radiation.
State the effect of the absorption or emission of radiation
on the energy levels of electrons in atoms or ions.
The wavelengths of radiation emitted and absorbed by an
element are unique to that element.
State that the wavelengths of radiation emitted and
absorbed by an element are unique to that element.
The wavelengths of radiation absorbed by an element can be
used to identify its presence in a sample.
Explain the principles of atomic absorption spectroscopy in
identifying elements in a sample.
Atomic absorption spectroscopy is used for quantitative
analysis.
Describe the construction and use of calibration graphs in
determining the concentration of an element in a sample.
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Topic 3: Using and Controlling Reactions
The use and control of chemical reactions are important tasks undertaken by chemists. This topic looks at the
energy changes that accompany chemical reactions and their rates and extents. It also examines the ways in which
chemical reactions are controlled and used to make materials and generate the energy needed by a modern
industrial society.
The increased use of energy from chemical reactions has been a major factor in the development of the
industrialised world. In this topic students consider the ways in which this energy is produced and begin quantitative
consideration of the energy changes that accompany chemical reactions.
The production of chemicals is the main function of the chemical industry. These chemicals allow naturally occurring
materials to be modified or replaced, and previously unknown materials to be developed. The industrialised world
depends on the chemical industry for the manufacture of a diverse range of materials. In this topic students look at
how chemicals are produced and how the production can be performed most efficiently.
Knowledge of chemistry can be applied to manipulate the reaction conditions of industrial processes in order to
determine the quantity or quality of the product.
3.1
Measuring Energy Changes
Key Ideas
Intended Student Learning
Almost all chemical reactions occur with either an absorption or a
release of heat or light energy. Other forms of energy, such as
electrical energy, can also be released.
Identify combustion and respiration as reactions that release
energy and photosynthesis as a reaction that absorbs
energy.
Exothermic reactions release energy to the surroundings, whereas
endothermic reactions absorb energy from the surroundings.
Deduce whether a reaction is exothermic or endothermic
from information provided.
The measurement of the heat change in chemical reactions is
called ‘calorimetry’; the insulated apparatus used for the
measurement is a calorimeter.
Calculate the heat released or absorbed for a reaction from
experimental data, given the specific heat capacity of water
(4.18 J g1 K1).
The heat released or absorbed in a reaction at constant pressure is
called the ‘enthalpy change for the reaction’; it is represented by the
symbol H.
Determine enthalpy changes from experimental data for
reactions, including:
 the combustion of alcohols
 the neutralisation of acids with bases
 solution processes.
Exothermic reactions have negative H values. Endothermic
reactions have positive H values.
Identify a reaction as exothermic or endothermic, given a
thermochemical equation or the value of its enthalpy
change.
Thermochemical equations express a quantitative relationship
between the quantities of reactants and the enthalpy change.
Write thermochemical equations that correspond to given
molar enthalpies of combustion, neutralisation, and solution.
The magnitude of the heat absorbed or evolved for a reaction is
directly proportional to the quantities of reactants involved.
Calculate the theoretical temperature change of a specified
mass of water or solution heated or cooled by a reaction,
given molar enthalpies and quantities of reactants.
3.2
Fuels
Key Ideas
Intended Student Learning
Carbon-based fuels provide energy and are feedstock for the
chemical industry.
Describe the advantages and disadvantages of the use of
carbon-based fuels as sources of heat energy, compared
with their use as feedstock.
Carbon dioxide and water are produced by the complete
combustion of compounds containing carbon and hydrogen.
Write balanced equations for the complete combustion of
fuels in which the only products are carbon dioxide and
water.
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Key Ideas
Intended Student Learning
The products of the incomplete combustion of carbon-based fuels
include carbon (soot) and carbon monoxide. Soot and carbon
monoxide are harmful to the environment.
Describe the undesirable consequences of incomplete
combustion.
Fuels can be compared on the basis of the quantity of heat
released.
Calculate the quantities of heat evolved per mole, per gram,
and per litre (for liquids) for the complete combustion of
fuels.
3.3
Electrochemistry
Key Ideas
Intended Student Learning
Electrochemical cells are conveniently divided into galvanic cells, which
produce electrical energy from spontaneous redox reactions, and
electrolytic cells, which use electrical energy from an external source to
cause a non-spontaneous chemical reaction.
Identify a cell as galvanic or electrolytic, given
sufficient information.
Redox reactions can be considered as two half-reactions, one involving
oxidation and the other reduction.
Write half-equations for half-reactions, including
those in acidic solution, given information about the
reactants and the products.
Galvanic and electrolytic cells involve oxidation at the anode and
reduction at the cathode, with electrons being transferred from one
electrode to the other through an external circuit.
Identify the anode and cathode in a galvanic cell or
an electrolytic cell, given information about the
reactants and the products.
Galvanic cells are commonly used as portable sources of electric
currents.
Identify the:
 charge on the electrodes
 direction of electron flow
 movement of ions in the salt bridge or electrolyte
given a sketch for a galvanic cell and information
about electrode reactions.
Fuel cells are galvanic cells in which the electrode reactants are
available in continuous supply.
State the advantages and disadvantages of fuel
cells compared with other galvanic cells.
Some galvanic cells can be recharged by using an external electrical
supply to reverse the electrode reactions.
Describe the complementary nature of the charging
and discharging of rechargeable galvanic cells.
Electrolytic cells are used in the production of active metals.
Describe, with the aid of equations, the electrolytic
production of active metals.
3.4
Rate of Reaction
Key Ideas
Intended Student Learning
The time taken for a reaction to reach a specified point is an
indication of the rate of the reaction.
Determine the effect of varying conditions on the rate of a
given reaction, using experimental data.
The rates of a reaction at different times can be compared by
considering the slope of a graph of quantity (or molar
concentration) of reactant or product against time.
Draw and interpret graphs representing changes in
quantities or concentration of reactants or products against
time.
The rates of a reaction are affected by changes in the:
 concentration of reactants
 temperature of the reaction mixture
 pressure of the reaction mixture (for systems involving gases)
 state of subdivision of reactants
 presence of catalysts (including enzymes)
 intensity of light (for photochemical reactions).
Predict and explain the effect that changes in condition
have on the rates of reactions in terms of the:
 frequency of collisions between reactant particles
 orientation of colliding particles
 energy of colliding particles
 activation energy.
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Key Ideas
Intended Student Learning
The energy changes in a reaction can be represented by an
energy profile diagram.
3.5
Draw and interpret energy profile diagrams that show the
relative enthalpies of reactants and products, the activation
energy, and the enthalpy change for the reaction.
Chemical Equilibrium
Key Ideas
Intended Student Learning
All chemical reactions carried out in a closed system at a fixed
temperature eventually reach a state of dynamic equilibrium in
which the concentrations of all the reactants and products
cease to change with time. The total mass of reactants and
products in a closed system remains constant.
Describe the dynamic nature of a chemical system at
equilibrium.
The position of equilibrium in a chemical system at a given
temperature can be indicated by a constant, Kc, related to the
concentrations of reactants and products.
Write Kc expressions that correspond to given reaction
The changes in concentrations of reactants and products as a
system reaches equilibrium can be represented graphically.
Draw and interpret graphs representing changes in
concentration of reactants and products against time.
The final equilibrium concentrations for a given reaction depend
on the:
 initial concentrations of the reactants and products
 temperature
Calculate the initial and/or equilibrium concentrations or
quantities of reactants and products, given sufficient
information about a particular system initially and/or at
equilibrium.
equations, and perform calculations involving Kc and
equilibrium concentrations in which all reacting species are
included in the expression.
 value of Kc
 pressure (for systems involving gases).
If a change is made to a system at equilibrium so that it is no
longer at equilibrium, a net reaction will occur (if possible) in the
direction that counteracts the change. This is a statement of Le
Châtelier’s principle.
Predict, using Le Châtelier’s principle, the effect on the
equilibrium position of a system of a change in the:
 concentration of a reactant or product
 overall pressure of a gaseous mixture
 temperature of an equilibrium mixture for which the
H
value for the forward or back reaction is specified.
3.6
Chemical Industry
Key Ideas
Intended Student Learning
In any industrial chemical process it is
necessary to select conditions that will give
maximum yield in a short time. This will often
involve compromises between conditions that
produce the maximum rate, conditions that
produce the maximum yield, and costs.
Explain the reaction conditions that will maximise yield.
The steps in industrial chemical processes can
be conveniently displayed in flow charts.
Interpret flow charts and use them for such purposes as identifying: raw
materials; chemicals present at different steps in the process; waste
products; and by-products.
3.7
Metal Production
Key Ideas
Stage 2 Chemistry 2014
Intended Student Learning
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Key Ideas
Intended Student Learning
The likelihood that an uncombined metal will occur
naturally increases with lack of reactivity.
Predict whether a metal is likely to occur in nature uncombined
or combined with other elements, given the relative position of
the metal in a table of metal reactivities.
The stages in the production of metals from their
ores include concentration of the mineral;
conversion of the mineral into a compound suitable
for reduction; reduction; and refinement of the metal.
Identify the stages in the production of a metal from its ore and
explain why not all stages are necessary in the production of
some metals.
The stages in the electrolytic production of zinc from
its ore are concentration of the zinc mineral;
conversion of the zinc mineral into a form suitable
for reduction; and electrolytic reduction.
Describe, with the aid of equations, the production of zinc from
its ore.
Electrolysis of molten electrolyte is used in the
reduction stage for the production of more reactive
metals.
Explain why the production of aluminium requires a molten nonaqueous electrolyte.
Reduction of the oxide using carbon can be used for
the production of less active metals.
Explain why zinc and iron can be obtained by reduction using
carbon whereas this is not possible for aluminium.
The method used in the reduction stage in the
production of a metal is related to the reactivity of
the metal.
Predict the likely method of reduction of a metal compound to
the metal, given the position of the metal in the activity series of
metals.
Energy cost is a factor taken into account in the
production of all metals.
Explain why reduction using electrolysis of an aqueous solution
is preferable to electrolysis of a melt.
Stage 2 Chemistry 2014
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Topic 4: Organic and Biological Chemistry
Most chemicals are compounds of carbon with other elements, mainly hydrogen, oxygen, and nitrogen, with many
more being synthesised each year. The variety and importance of carbon compounds are so great that there is a
specific branch of chemistry known as ‘organic chemistry’. In this topic students are introduced to the chemistry of
the more common organic compounds.
Biological chemistry is a growing area of research; it includes medical technology, genetic engineering, and the
development of pharmaceuticals. In this topic students are introduced to the major groups of compounds of
biological significance.
The reactions of the larger macromolecules can often be explained by referring to the reactions and properties of
smaller molecules with the same functional groups.
4.1
Systematic Nomenclature
Key Ideas
Intended Student Learning
The presence or absence of functional groups in an organic
compound determines its physical and chemical properties.
Identify the functional groups in the structural formulae of
alcohols, aldehydes, ketones, carboxylic acids, amines,
esters, and amides.
Organic compounds are named systematically to provide
unambiguous identification.
State, given its structural formula, the systematic name of an
organic compound containing:
 up to eight carbon atoms arranged as either a straight
chain or a branched chain
 one or more of the same functional groups (with these
limited to hydroxyl, aldehyde, ketone, carboxyl, or primary
amino groups).
The structural formula of an organic compound can be
deduced from its systematic name.
Given its systematic name, draw the structural formula of an
organic compound containing:
 up to eight carbon atoms arranged as either a straight
chain or a branched chain
 one or more of the same functional groups (with these
limited to hydroxyl, aldehyde, ketone, carboxyl, or primary
amino groups).
Esters are named as derivatives of a carboxylic acid.
State the systematic names of methyl and ethyl esters of
straight-chain acids containing up to eight carbon atoms.
The structural formula of an ester can be deduced from its
systematic name.
Given its systematic name, draw the structural formula of an
organic methyl or ethyl ester of a straight-chain acid
containing up to eight carbon atoms.
4.2
Physical Properties
Key Ideas
Intended Student Learning
The melting points and boiling points of organic compounds
that contain the same functional group increase with the
length of carbon chain.
Predict and explain the melting points and boiling points of
an organic compound in comparison with those of other
compounds that contain the same functional group.
The boiling points of organic compounds that display
hydrogen bonding between molecules are higher than those
of compounds of similar molar mass that do not display
hydrogen bonding.
Predict and explain the boiling points of alcohols in
comparison with those of aldehydes and ketones of
similar molar mass.
The boiling points of esters are lower than those of isomeric
acids because of the absence of hydrogen bonding between
molecules of the ester.
Predict and explain the boiling points of esters in
comparison with those of isomeric acids.
Organic compounds are generally insoluble in water.
Explain the insolubility in water of most organic
compounds.
Stage 2 Chemistry 2014
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Key Ideas
Intended Student Learning
Hydrogen bonding between functional groups and water can
explain the solubility in water of some smaller organic
compounds.
Predict and explain the solubility in water of the smaller
amino acids, carboxylic acids, alcohols, aldehydes, and
ketones.
The solubility in water of an organic compound depends on
its molar mass and the functional groups present.
Predict and explain the relative solubilities in water of two
organic compounds, given their structural formulae.
4.3
Alcohols
Key Ideas
4.4
Ethanol is produced by the fermentation of glucose, which can
be derived by the hydrolysis of complex carbohydrates.
Describe the conditions, and write equations, for the
hydrolysis of polysaccharides and disaccharides, and
the production of ethanol by the fermentation of
glucose.
Alcohols are classified as primary, secondary, or tertiary.
Identify a hydroxyl group in an alcohol as primary,
secondary, or tertiary, given the structural formula.
Primary and secondary alcohols can be distinguished from
tertiary alcohols by their reaction with acidified dichromate
solution.
Describe how primary and secondary alcohols can be
distinguished from tertiary alcohols by their reaction
with acidified dichromate solution.
The type of product obtained by oxidising an alcohol depends
on whether the alcohol is primary or secondary.
Predict the structural formula(e) of the product(s) of
dichromate oxidation of a primary or secondary
alcohol, given its structural formula.
Aldehydes and Ketones
Key Ideas
4.5
Intended Student Learning
Intended Student Learning
Aldehydes and ketones are produced by the oxidation of the
corresponding primary and secondary alcohols respectively.
Aldehydes are readily oxidised and so must be distilled off from
the reaction mixture as they are formed.
Given the structural formula of the aldehyde or
ketone, draw the structural formula of the alcohol
from which it could be produced by oxidation, and
describe the necessary reaction conditions.
Aldehydes can be oxidised to form carboxylic acids or, in
alkaline solutions, carboxylate ions.
Draw the structural formula of the oxidation product
of a given aldehyde in either acidic or alkaline
conditions.
Ketones cannot readily be oxidised. This difference in
properties between aldehydes and ketones can be used to
distinguish one from the other.
Describe how acidified dichromate solution and
Tollens’ reagent (ammoniacal silver nitrate solution)
can be used to distinguish between aldehydes and
ketones.
Carboxylic Acids
Key Ideas
Intended Student Learning
Carboxylic acids can be produced by the oxidation of aldehydes
or primary alcohols.
Identify the aldehyde or primary alcohol from which a
carboxylic acid could be produced by oxidation, given
its structural formula.
Carboxylic acids are weak acids and, to a small extent, ionise in
water.
Write an equation for the ionisation of a carboxylic
acid in water.
Carboxylic acids react with bases to form ionic carboxylate
salts.
Write equations for the reactions of carboxylic acids
with hydroxides, carbonates, and
hydrogencarbonates, and describe changes that
accompany these reactions.
Stage 2 Chemistry 2014
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Key Ideas
Intended Student Learning
The salts of sodium and potassium carboxylates are soluble in
water because of the ion–dipole attraction between the ions and
water.
4.6
Explain why some drugs with carboxyl groups are
usually taken in the form of their salts.
Amines
Key Ideas
Intended Student Learning
Owing to the presence of an unbonded electron pair,
amines are able to act as bases and accept H+ ions.
Draw the structural formula of the protonated form of an
amine, given the structural formula of its molecular form,
and vice versa.
Amines are classified as primary, secondary, or tertiary.
Identify an amino group in an amine as primary, secondary,
or tertiary, given the structural formula.
The salts of amines are soluble in water because of the
ion–dipole attraction between the ions and water.
Explain why some drugs with amine groups are usually
taken in the form of their salts.
4.7
Esters
Key Ideas
Intended Student Learning
An ester can be produced by a condensation reaction between
an alcohol and a carboxylic acid.
Draw the structural formula of the ester that could be
produced by the condensation reaction between an
alcohol and a carboxylic acid, given their structural
formulae, and write an equation for the reaction.
The production of an ester from the reaction of an alcohol and a
carboxylic acid is slow at 25°C.
Explain the use of heating under reflux and the presence
of a trace of concentrated sulfuric acid in the laboratory
production of esters.
Esters may be hydrolysed under acidic or alkaline conditions.
Identify the products of hydrolysis of an ester, given its
structural formula.
4.8
Amides
Key Ideas
Intended Student Learning
An amide can be produced by a condensation reaction
between an amine and a carboxylic acid.
Draw the structural formula of the amide that could be
produced by the condensation reaction between an amine
and a carboxylic acid, given their structural formulae.
Amides may be hydrolysed under acidic or alkaline
conditions.
Identify the products of hydrolysis of an amide, given its
structural formula.
4.9
Proteins
Key Ideas
Intended Student Learning
Amino acids contain a carboxyl group and an amino group.
Determine whether or not a compound is an amino acid,
given its structural formula.
Amino acids can self-ionise to produce an ion.
Draw the structural formula of the product formed when an
amino acid self-ionises.
Proteins are large molecules in which amide groups link
monomer units. In proteins the amide group is called a
‘peptide link’ or a ‘peptide bond’.
Identify the amide group and deduce the structural
formula(e) of the monomer(s), given the structural formula
of a section of a protein.
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Key Ideas
Intended Student Learning
Proteins are polyamides consisting of covalently bonded long
chains of amino acid units.
Write the general formula of amino acids and recognise
their structural formulae.
Proteins have sites that allow hydrogen bonding between
sections of chains and between the chain and water.
Identify where hydrogen bonding can occur between
protein chains or between the chain and water, given the
structural formula of a section of the chain.
The biological function of a protein is a consequence of its
unique spatial arrangement.
Explain why the biological function of a protein (e.g. an
enzyme) is altered if its spatial arrangement is altered.
Changes in pH and temperature disrupt the secondary
interactions, and hence the spatial arrangements, of a protein
chain.
Explain why proteins are sensitive to changes in pH and
temperature.
4.10 Triglycerides
Key Ideas
Intended Student Learning
Edible oils and fats are esters of propane-1,2,3-trio (glycerol)
and various carboxylic acids. The carboxylic acids are
unbranched and usually contain an even number of carbon
atoms between twelve and twenty.
Draw the structural formula of an edible oil or fat, given
the structural formula(e) of the carboxylic acid(s) from
which it is derived.
Triglycerides can be hydrolysed to produce propane-1,2,3triol and various carboxylic acids.
Identify the alcohol and acid(s) from which a triglyceride
is derived, given its structural formula.
Edible oils are liquids at 25°C and are commonly obtained from
plants and fish. Edible fats are solids at 25°C and are
commonly obtained from land animals.
Identify the most likely source of a triglyceride, given its
state at 25°C.
Most liquid triglycerides contain a larger proportion of
unsaturated carbon chains than solid triglycerides contain.
Describe and explain the use of a solution of bromine or
iodine to determine the degree of unsaturation of a
compound. Draw the structural formula of the reaction
product.
Liquid triglycerides can be converted into triglycerides of higher
melting point by a process that involves the addition of
hydrogen under pressure and at increased temperature, in the
presence of a catalyst.
Explain the role of pressure, temperature, and a catalyst
in the hydrogenation of liquid triglycerides.
4.11 Carbohydrates
Key Ideas
Intended Student Learning
Carbohydrates are naturally occurring sugars and their
polymers. They usually have the general formula CxH2yOy.
They are defined more precisely as either polyhydroxy
aldehydes or polyhydroxy ketones, or their polymers.
Given its structural formula, determine the molecular
formula of an organic compound, and whether or not it is
a carbohydrate.
Carbohydrates can be classified as monosaccharides,
disaccharides, or polysaccharides.
Write molecular formulae for glucose, and for
disaccharides and polysaccharides based on glucose
monomers.
Polysaccharides are produced by the condensation of many
monosaccharide units linked in chains by covalent bonds.
Identify the repeating unit and draw the structural formula
of the monomer, given the structural formula of a section
of a polysaccharide derived from one monomer.
Glucose molecules can occur in either a chain form or a ring
form. There is equilibrium between the two structures. In the
chain form an aldehyde group is present.
Explain the ability of glucose to react as an aldehyde
when in chain form but not when in ring form.
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Key Ideas
Many simple carbohydrates are soluble in water, whereas
polysaccharides are insoluble in water.
Stage 2 Chemistry 2014
Intended Student Learning
Explain the differences in solubility in water of simple
carbohydrates and polysaccharides in terms of the size
of the molecules and the number of hydroxyl groups.
47
Topic 5: Materials
In this topic students consider the chemical and physical properties of a range of materials and develop an
understanding of the chemistry behind these properties. Polymers are important in nature and synthetic polymers
represent one of the benefits of scientific advances.
Silicates and aluminosilicates are the most common materials in the Earth’s crust. They form the basis of rocks and
most minerals and are the major components of soils. The silicates of which they are composed determine the soils’
chemical properties. Healthy soils are essential for sustainable food production.
Cleaning agents are familiar household chemicals that help in the maintenance of a healthy lifestyle. They function
in a variety of ways that include dissolving, suspension, and oxidation.
5.1
Polymers
Key Ideas
Intended Student Learning
The production of synthetic polymers allows the manufacture
of materials with a diverse range of properties.
Discuss the advantages and disadvantages of synthetic
polymers.
Polymers or macromolecules are very large molecules
composed of small repeating structural units.
Identify the repeating unit of a polymer, given the structural
formula of a section of a chain.
Polymers are produced from small molecules (monomers) by
one of two main polymerisation reactions: addition or
condensation.
Identify a polymer as being the product of an addition
polymerisation or a condensation polymerisation, given its
structural formula.
Addition polymerisation occurs when monomer molecules link
without the loss of atoms. The monomer usually has at least
one
carbon–carbon double bond per molecule.
Draw the structural formula of an addition polymer that could
be produced from monomers containing one carbon–carbon
double bond, given the structural formula(e) of the
monomer(s), or vice versa.
Polyesters and polyamides are large molecules in which
monomer units are linked by ester and amide groups
respectively.
Identify the ester group in a polyester and the amide group in
a polyamide.
Condensation polymerisation occurs when one or more
compounds (such as water) are produced as the monomer
molecules link.
Draw the structural formula(e) of the polyester or polyamide
polymers that could be produced from monomers, given the
structural formula(e) of the monomer(s), or vice versa.
Organic polymers can have different properties, such as
rigidity, depending on the monomers and the degree of crosslinking between chains.
Describe the effect on rigidity of increasing the number of
primary and secondary interactions between polymer chains.
Heat affects thermoplastic and thermoset polymers
differently.
Describe the effects of heating on thermoplastic and
thermoset polymers, and the consequent difference in the
ease of recycling.
5.2
Silicates
Key Ideas
Intended Student Learning
Silicon dioxide, silicates, and aluminosilicates are
important components of rocks and soils.
Write the formula of the anion in a silicate or aluminosilicate,
given its formula.
The structure of silicates is based on SiO4 tetrahedra.
Identify the SiO4 structural unit in diagrams of silicate anions.
In silicates, oxygen atoms can be shared between two
SiO4 tetrahedra.
Draw the repeating unit and write the formula of an extended
silicate anion, given its structural formula.
In silicates the oxidation state of silicon is 4 whereas
that of oxygen is 2.
State the charge on a silicate anion, given the Si:O ratio.
The charge balance in silicate minerals is achieved by
the presence of cations, most commonly
Ca2+, Mg2+, K+, Na+, Fe2+, and Fe3+.
Write the formula of a silicate mineral, given the structural
formula of the silicate anion and the metal ions present.
Stage 2 Chemistry 2014
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Key Ideas
Intended Student Learning
In minerals known as ‘aluminosilicates’, aluminium
atoms replace some of the silicon atoms.
State the charge of an aluminosilicate ion, given its formula.
Cations held on the surface of soil silicates are in
equilibrium with the cations in soil water, which are
available as sources of plant nutrients.
Explain how cations held on the surface of soil silicates are
made available to plants.
Soil silicates are able to adsorb H+ in the soil water and
release cations.
Describe the effect of acid rain in releasing cations from soil
silicates.
The surface of fine silicate particles in clays is
negatively charged and can be flocculated into larger
particles by the addition of salts containing highly
charged cations such as aluminium ions.
Explain the use of aluminium ions in flocculating clay particles
suspended in water.
Silicates such as zeolites are able to soften water by the
exchange of cations.
Explain the use of silicates in water softeners.
5.3
Cleaning Agents
Key Ideas
Intended Student Learning
Many stains can be removed by the use of an appropriate
solvent.
Describe the use of non-polar solvents to dissolve nonpolar materials and the use of polar solvents to dissolve
polar materials.
Soaps and synthetic sulfonate detergents consist of a nonpolar hydrocarbon chain, which is hydrophobic, and an
ionic region, which is hydrophilic.
Describe and explain how soaps and synthetic sulfonate
detergents remove grease.
Fats and oils can be hydrolysed by boiling with sodium
hydroxide solution. The carboxylate salts formed are
soaps.
Write equations for the alkaline hydrolysis of triglycerides.
Soaps form an insoluble material when used in hard water.
Write an equation for the formation of magnesium or
calcium precipitate from soap, given the structural formula
of the soap anion.
The effectiveness of soaps is significantly reduced when
they are used in hard water, whereas the effectiveness of
synthetic detergents is not greatly changed when they are
used in hard water.
Describe how the reaction of soap with hard water differs
from that of synthetic detergents.
The structure of phosphates is based on PO4 tetrahedra.
Draw the structural formula of the PO43 ion.
In tripolyphosphates, oxygen atoms can be shared
between PO4 tetrahedra.
Draw the structural formulae of linear and cyclic
tripolyphosphate ions.
Tripolyphosphates are added to many detergent
formulations.
Explain how tripolyphosphate ions keep: calcium and
magnesium ions in solution; clay particles in suspension;
and pH mildly alkaline.
Tripolyphosphates improve the effectiveness of detergent
formulations.
Explain the importance of the actions of tripolyphosphate
ions.
Phosphates can cause eutrophication in water bodies.
Describe the advantages and disadvantages of the use of
phosphate fertilisers and polyphosphates in detergent
formulations.
Chlorine bleaches are most stable at a pH above 7.
Explain the effect of lowering pH on the decomposition of
hypochlorites to chlorine.
Enzymes are added to some detergent formulations.
Describe the use of enzymes in detergents and explain
why they are sensitive to changes in pH and temperature.
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Key Ideas
Intended Student Learning
Solid oxygen bleaches release hydrogen peroxide as an
oxidising agent. Hydrogen peroxide decomposes to release
oxygen.
Use the change in oxidation number of oxygen to show
hydrogen peroxide and oxygen acting as oxidising agents.
Solid oxygen bleaches are added to some detergent
formulations because they release hydrogen peroxide and
hence oxygen in solution.
Describe how solid oxygen bleaches release oxidising
agents when dissolved in water.
Stage 2 Chemistry 2014
Explain why the effectiveness of solid oxygen bleaches is
affected by changes in temperature.
50