Download Review guide for Chemistry`s First Semester Exam Unit 1 Thinking

Review guide for Chemistry’s First Semester Exam
Here are the learning goals with some sample questions that will help you prepare for the semester exam. The learning
goals appear in bold font and the problems are in regular. Pages of your text book are sometimes given, in case you need more
support. All of the materials handed out in class are available to be downloaded from Mr. Botella’s website. Go to Chemistry and
look under handouts. You might need more paper for answering the questions.
Unit 1 Thinking like a Chemist
I will be able to…
Identify common lab equipment (graduated cylinder, beaker, test tube)
1. Sketch each of the following glassware:
a. Beaker
b. Flask
c. Graduated cylinder
d. Test tube
Properly measure objects using lab equipment (eg. volume, length, mass).
2. What is the length of the following object (Remember to guess up to one more digit from instrument’s precision
and do not forget the units!)
The length of the object is 7.45 cm approximately
Convert numbers that are in scientific notation into numbers written in ordinary notation and vice versa.(P.48 TXT)
3. Write the following numbers into correct scientific notation:
a. 1023 = 1.02x103
d. -56894 = -5.69x104
b. 0.000054 = 5.4x10-5
e. -0.000593 = -5.93x10-4
c. 125.89 = 1.26x102
f. 4897x104 = 4.90x107
4. Write the following numbers into regular notation
a. 1.25x103 = 1250
d. 165.89x102 = 16589
b. 0.00034x10-2 = 0.0000034
e. 9.573x10-4 = 0.0009573
c. 4.45x10-6 = 0.00000445
f. -2.36x104 = -23600
Do addition, subtraction, multiplication, and division of numbers written in scientific notation (P. 48 and 56 TXT)
5. Find the correct value for the following operations without a calculator
a. 2.00x10-2 + 4.00x10-1 = 4.2x10-1
b. 9.00x109 – 3.00x108 = 8.7x109
c. 4.00x104 * 2.00x102 = 8x106
d. 5.00x10-4 * 5.00x104 = 25x100 = 2.5x101
e. 1.50x106 / 3.00x103 = 5x102
6. Find the correct value for the following operations. You can use your calculator this time.
f.
3.65x10-5 + 6.19x10-6 = 4.27x10-5
g. 1.87x109 – 8.7x108 = 1x109
h. 4.67x106 * 6.95x103 = 3.25x1010
i.
9.56x106 / 3.20x10-2 = 2.9x108
Define and write the equation for density
7. Define density and write its equation
Density is defined as the ratio between mass and volume (D=m/v). Density measure how compact matter
is. A denser object will have the same amount of matter in a smaller volume
Know the value for the density of water
8. Write the value of density for pure water: 1 g/cm3
Know what makes one substance more dense than a different substance
9. If you have 1 kg of lead and 1 kg of cotton, which takes up more space?
Since lead is denser than cotton, 1 kig of lead takes less space than 1 kg of cotton
10. If you have a volume of 10 cm3 of lead and another volume of 10 cm3 of cotton, which one is heavier?
Since lead is denser than cotton, 10 cm3 of lead has a lot more matter than 10 cm3 of cotton
Know that the density of a substance does not depend on the size of the object.
11. Explain what happens to the density of a homogenous object (say a piece of paper) when we cut it in half
The density does not change when we cut a homogenous object in half. The new pieces will have half the mass
and will take half the volume.
Calculate the density of an object, given its mass and volume.
12. Find the density of a plastic cube that has a volume of 3cm3 and a mass of 6.2 g
v=3 cm3 = 3 ml
D=m/v = 6.2 g / 3 cm =2.07 g/ml
m=6.2 g
D=?
Calculate the density of an object, given its mass and volume.
13. Find the volume of the ball that has a mass of 500 g and a density of 1.68 g/ml
m= 500 g
D=m/v therefore v = m/D = 500 g / 1.68 g/ml = 297.6 ml
D= 1.68 g/ml
V=?
Calculate the mass of an object, given its density and volume.
14. Calculate the mass of a portfolio if you know its density is 2.3 g/ml and its volume is130 cm3
m= ?
D=m/v therefore m = v*D = 130 ml * 2.3 g/ml = 299 g
D= 2.3 g/ml
V= 130 cm3 = 130 ml
Predict an objects relative density based on whether it floats or sinks in a liquid of known density (such as water).
15. You place three liquids that cannot mix in a beaker. You know the one labeled A is water (density of 1 g/ml), B
is an oil (density .7 g/ml), and C is a mysterious liquid whose density is 0.89 g/ml. Which of the liquids would be
on top, and which in the bottom.
Denser liquids go below less dense liquids. Water (A) will be on the bottom, mysterious liquid C will be in the
middle and the oil (B) will be on top.
Know the metric prefixes: kilo, centi, milli, micro
16. Define what each prefix means in terms of the unit value. For example, Kilo means 1000 times de unit value
a)Centi is a hundredth of the unit
b)Mili is a thousandth of the unit
c) Micro is a millionth of the unit
Define metric system, unit conversion and conversion factors
17. Define the metric system and indicate in what number is the metric system based
Metric system is a system of measurements based on the number 10
18. Define metric conversion by indicating what do we use this for
Metric conversion is used for transforming one unit in the metric system to another one. For example, to convert
a number of kilometers to centimeters
19. Define a conversion factor (what is a conversion factor?)
Conversion factors tell the equivalence between different units. For example 1 km = 100000 cm (1x105)
Convert from one metric prefix to another using the table of metric prefixes.
20. Do the following metric conversions:
a. 53 m = 5300 cm
c. 0.9 mg = 0.0009 g = 9x10-4 g
b. 145 kl 14500000 cl
d. 67 mm = 0.000067 km = 6.7x105 km
Solve unit conversion problems involving more than one conversion factor.
a. You heard a loud thump! while walking the dog one evening. You turned around the broken tree to find a
meteorite! You called your meteorite hunter friend in Paris and she asks about the weight of the meteorite in
kilograms. You only have a balance that reads in ounces and find the meteorite’s mass to be 53 ounces. How
many kilograms is this equal to (2.2 pounds = 1 kilograms; 16 ounces = 1 pound)? Use conversion factors to
solve this problem in the space below.
Weight in ounces = 53 oz convert to kilograms
53
1 1
∗
∗
= 1.51
1
16 2.2
b. A friend tells you he measured an oceanic current’s speed to be 5 m/s. How fast is that in miles per hour? Use
the following conversion factors to solve the problem :1 mile = 1508 m, 1 km = 1000 m; 1 h = 60 min; 1 min =
60 sec
Speed of current: 5m/s convert to miles per hour.
5 1
60 60
∗
∗
∗
= 11.9
1508 1
1ℎ
ℎ
Unit 2
Know these terms:
Use these terms to complete the web:
matter
atom
element
mixture
molecule
Classification of Matter
pure substance
homogenous mixture
solution
heterogenous mixture
compound
MATTER
Anything that has weight and takes up space
Homogeneous
Matter which looks the same throughout
Can be either
Heterogeneous
Matter which looks different throughout
Pure substance
Mixture
A kind of material with the same
composition throughout
Compound
Made up of more than one type of
atom; substance can be broken
down by simple chemical means
Made up of 2 or more substances; are
physically combined; composition varies
throughout
Element
A substance which cannot be
broken down further
Solution
Atom
Molecule
Special Case: A homogenous mixture that is
physically combined
Smallest unit of an
element
Smallest unit of a
compound
Review the symbols and names of commonly used elements (p.22)
Identify the symbols and names of the 7 diatomic elements:
Hydrogen, H
Iodine, I
Oxygen, O
Fluorine, F
Nitrogen, N
Chlorine, Cl,
(remember HONClBrIF)
Bromine, Br
Distinguish between an element and a compound symbolically
Identify each as an Element (E) or a Compound (C )
E Au
E Br2
C H2O
C CO2
E He
C NaCl
Describe the difference between an element and a compound
Element: An element is made out of the same type of atoms
Compound: Compouinds are made out of at least two different types of atoms that are combined chemically
Distinguish between an atom and a molecule symbolically
Identify the following as an atom (A) or a molecule (M)
A He
M NaCl
M CuBr
AP
M SO4
A Mg
Describe the difference between an atom and a molecule
Atom: An atom is the smallest unit of an element
Molecule: Molecules are made of more than one atom chemically combined. The atoms can be of the same or
different type (which means that diatomic elements make molecules by having two of their atoms chemically
combined, for exampleH2)
Identify examples of a homogenous mixture and a heterogenous mixture
Identify each of the following mixtures as homogeneous (HO) or heterogenous (HE)
HO Table Salt (NaCl)
HO Gold (Au)
HEChocolate Chip Cookie Dough
HO Lemonade
HO Shampoo
HO Well-Mixed Salt Water
Describe the difference between physical and chemical changes
Change in Matter
Chemical Change
Definition: Chemical change is a change in matter in
which the composition of molecules changes.
Physical Change
Definition: Physical change is a change
in matter that does not change the
composition of matter (all molecules
remain as the same molecule).
Signs of chemical changes:
Change in color
Change in odor
Change in temperature
Formation of a precipitate
Release of (light (flames, sparkles,light)
Formation of bubbles (except outgassing by pressure
differences)
Signs of physical changes:
Change in shape (broken glass)
Change in state of matter (evaporation,
melting)
Identify examples of chemical and physical changes
Label the following as a chemical change (C) or a physical change (P)
P glass breaking
C burning toast
C frying an egg
C spoiling (rotting) food
C a rusting nail
P making salt water P melting ice cream P mowing the lawn
Identify examples of chemical properties and physical properties
Identify the following as a chemical property (C) or a physical property (P)
P Color
P Taste
C Ability to rust
P Boiling point
P Ability to dissolve
P Density
P Odor
P Melting point
C Flammability
P Freezing point
Unit 3: Atomic structure, Periodic Table, and Sublevel Notation
Explain the difference between science and pseudoscience
Characteristics of Pseudoscience
Based in believes, not evidence
Untestable claims
Secretive (Not tested by others)
Relies in confirmation, not
contradiction
Criteria for Scientific Models
Based on evidence (data and facts)
Testable claims
Continuously tested by others
Relies on contradictions (valid if no
contradictions are found)
Define: atom, neutron, proton, electron, atomic mass, atomic number
19
This is the number of protons positively charged particles. This
is also referred to as the atomic number
K
This is the average atomic mass which you can calculate by adding the
number of protons and neutrons
39.098
An _________ is the smallest unit of matter.
An electron is a negatively charged particle, with essentially no mass.
Now draw a sketch of a K atom, showing the correct location and number of neutrons, protons, and electrons:
+p = 19
N = 20
2
8
8
1
Define: ion, cation, anion, oxidation number
Ion is any charged particle. Ions have a charge because they have different amount of protons and electrons.
Cation is a positive ion
Anion is a negative ion
Oxidation number is the charge of an ion
Match the items to the statement. Some items can be used more than once, and some statements have two
correct answers. Fill in all answers that apply!
8. Has/have more electrons than protons. A
9. Not an ion.
C
10. Cation(s)
D and B
A.
B.
C.
D.
Cl-2
K+1
F
Al+3
11. Anion(s)
A
12. Has/have gained electrons.
A
13. Has/have lost electrons.
D and B
Looking at the ions in the box above, circle the oxidation numbers. Define oxidation number in your own
words:
Oxidation number is the charge of an ion. Oxidation numbers above are the -2 above Cl, +1 above K and +3 above Al
Understand how the periodic table is organized. Know where important families are located. For more
help, read chapter 5, sections 1 & 2 (p. 124-140) in your textbook.
Using the periodic table above, color the Noble Gases red. Give the number of valence electrons of this family: 8
Color the Halogens green. Give the number of valence electrons of this family: 7
Circle the Diatomic Elements.
Shade in the Metalloids. On what side of the Metalloids are Metals located? Left Non-metals? Right
The direction of a Period: ↔ and a Family: ↕
Describe what elements in the same period have in common: Elements in the same period have the same number of
energy levels
Describe what elements in the same family have in common:
Elements in the same family have the same valence electrons, and same type of last sublevel
Describe how properties (atomic radius, ionization energy, valence electrons) change going across a period
or down a column (family). Read p. 142-148 in your textbook.
Define: Atomic Radius
The distance between the edge of an atom and its
center since it is hard to define the edge of an
atom, it is defined as half the distance between the
centers of two identical adyacent atoms
Define: Ionization Energy
The energy required to remove an electron from
the atom
How does this property change going across a
period? decreases
…down a family? decreases
How does this property change going across a
period? Increases
…down a family? Increases
Define Periodic and make a drawing to show what a periodic trend looks like:
Periodic means: a property is said to be periodic if it repeats over and over
Periodic looks like:
Describe the main characteristics of different types of elements (metals, metalloids, non-metals). See p. 17-19 in
your book.
Fill in the Venn diagram below to show which properties are unique to metals, metalloids, and non-metals, and which
properties two groups may
share:
Metalloids
Non-Metals
Metals
Shinny
Silver grey (save Cu
and Au)
Good conductors of
energy and electricity
Maleable (make sheets)
and ductile (cables)
Solid (save Hg)
Conduct
like metals
when
impure
Poor
conductors
when pure
opaque
multicolor
Poor conductors of
energy and electricity
Britle
Solid (s), liquid (Br),
and gases (N, O, H,
etc.)
Write the electron configuration for any element (sublevel notation) by reading the periodic table
Give the sublevel notation for the following elements:
Carbon 1s22s22p2
Lead 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p2
Copper 1s22s22p63s23p64s23d9
Identify the following elements according to their sublevel notations:
1s22s22p63s23p5 Chlorine (Cl)
1s22s22p63s23p64s23d104p65s24d9 Silver (Ag)
1s22s22p63s23p64s23d104p65s24d105p66s24f145d5 Rhenium (Re)
Write the electron configuration using the noble gas short hand
Give the sublevel notation for the following elements, using the noble gas short hand
Cl [Ne]: 3s23p5
Pr [Xe]: 6s24f3
Sb [kr]: 5s24d105p3
Find the oxidation number of elements by:
a) drawing the atomic sketch of the element or b) looking at the periodic table
Draw the atomic sketch for As AND show its number of valence electrons using an electron dot symbol, for example,
+p = 33
N = 42
2
8
18
X
5
As
Draw the atomic sketch for Ba AND show its number of valence electrons using an electron dot symbol
+p = 56
N = 81
2
8
18
18
8
2
Ba
Describe how you can tell the number of valence electrons from looking at the atomic sketch: The valence electrons are the
electrons in the last sublevel (actually, thee electrons in the S and P sublevels only)
What is another way you can tell the number of valence electrons, by looking at the periodic table?
For the elements in the S and P blocks, the number of their column is equal to the number of valence electrons. This is not
true for elenments in d and f blocks, since all of them have 2 valence electrons.
Unit 4: Copper lab, Writing formulas, Naming compounds
Define Reactant and products, precipitate, exothermic and endothermic reactions and signs of each
Write the definition of the following terms:
1. Reactants and products: Reactants are thesubstances that participate in a chemical reaction as the
starting points. Products are the substances that form in a chemical reaction
2. Precipitate: Precipitate is a solid that forms within a liquid as a product of a chemical reaction
3. Exothermic reaction and endothermic reaction An exothermic reaction releases energy to its
environment (feels hot), and an endothermic reaction absorbs energy from its environment (feels cold)
Define the symbols (aq), (s), (l), (g), and explain when to use these symbols
In the reaction below, explain what do the symbols (aq), (l), (g) mean.
Cl2(g) + KBr(aq) → KCl(aq) + Br2(l)
(aq) states that the substance is dissolved in water
(l) states that the substance is a liquid with no water
(g) states the substance is a gas
(s), not present in this reaction, states the substance is a solid
What is the difference between the following sy,mbols for hydrochloric acid
HCl(aq) and HCl(l)
HCl(l) is pure hydrochloric acid with no water, but still a liquid, while HCl(aq) is hydrochloric acid that has been dilited
in water.
Describe five signs that a chemical change has occurred
List five evidences that a chemical change has occurred, and provide examples for each from the copper lab
Change in color: When the solod cipper was mixed with the colorless nitric acid and formed a deep blue copper II
nitrate
Change in odor: In the same reaction nitrogenmonoxide wsa fromed and smelled bad
Change in temperature: Whan aluminium wire was added to the copper II chloride and the beaker got very hot
Formationo of a precipitate: The warming up of copper hydroxide produced the precipitate of copper II oxide
Bubbling gas: the reaction of aluminium and copper II nitrate released a lot of gas
Describe the following laboratory techniques: decanting, water bath and gravity filtration
Describe each of the following lab procedures by indicating what is the main goal for using the procedure, and
indicate when you would use them.
1. Decanting Decanting is a technique used for removing excess water from a mixture of solid and liquid
or two liquids that do not mix (immiscible). The beaker is tilted until to pour the upper liquid, and a
stirring rod is placed at the edge of the mouth of the beaker to allow the liquid to flow down around it.
2. Water bath A water bath is used when we want to keep the temperature at a certain value. A cold water
bath is used to cool down the reaction while a hot water bath is used to warm it up
3. Gravity filtration Gravity filtration is used for separating liquids from solids. A filter is folded in fourths
and placed on a funnel. The liquid is poured into the filter and another beaker isplaced below the funnel
to recover the filtered liquid. The solid is removed from the filter at the end.
Describe the criss-cross method for writing chemical formulas based on the fact that compounds have no overall
charge.
Write down the steps you would take for writing the chemical formula of a given compound
1. Find the oxidation number ofr the ions involved in the compound
2. Write the cation to the left (+), and the anion (-) to the right
3. If the sum of the oxidation numbers is different from zero, then write as the subscript of the cation the
oxidation number of the anion, without the sign, and the oxidation number of the anion, without the sign, as
the subscript of the cation.
Write the correct chemical formula for the following compounds:
1. potassium chromate K2(CrO4)
2. magnesium nitrate
Mg(NO3)2
3. copper I phosphate Cu3(PO4)
4. copper II phosphate Cu3(PO4)2
5. ammonium sulfate
(NH4)2(SO4)
6. iron II dichromate
Fe(Cr2O7)
7. iron III dichromate Fe2(Cr2O7)3
8. copper I bromide
CuBr
9. copper II bromide
CuBr2
10. magnesium oxide
MgO
Write the correct name for a compound when you are given its chemical formula (in symbols)
Write down the steps you would take for naming compounds given its formula
Write the correct name for the following compounds:
1. K3N
potassium nitride
2. Fe2(CO3)3 Iron III carbonate
3. Sn(Cr2O7) Strontium II dichromate
4. (NH4)2(SO4) ammonium sulfate
5. Ag2(SO3)
Silver sulfate
6. NO3
Nitrogen trioxide
7. Li(OH)
Lithium hydroxide
8. SF6
Sulfur hexaflouride
9. C I4
Carbon tetraiodide
10. Pb(C2H3O2)2 Lead acetate
11. BaCl2
Barium II Chloride
12. Cs3P2
Caesium II phosphide
13. Sr(NO2)2
Strontium II nitrate
14. Cr(SO4)
Chromium II sulfate
15. Zn3(PO4)2 Zinc II phosphate
Write a correct chemical reaction, including the reactants and products
Write the symbols for the following equation, including the symbols (aq), (l), (g) ot (s) for each compound. Circle the
reactants and square the products
1. Silver sulfate dissolved in water and pieces of sodium yield a precipitate of silver and a solution of sodium sulfate
dissolved in water
Ag2(SO4)(aq) + Na
Ag(s) + Na2(SO4)(aq)
2. The solutions of Lead II nitrate and potassium iodide, both dissolved in water, produce a precipitate of lead iodide
and the diluted solution of potassium nitrate
Pb(NO3)2(aq) + KI(aq)
PbI2(s) + K (NO3)(aq)
Unit 5
Reaction Types and predicting products
Define:
The five major types of reactions: combination, decomposition, single replacement, double replacement, and
combustion of a hydrocarbon.
Identify the following reaction types:
A + B → AB Combination (synthesis in your textbook)
A + BC → B + AC
Single replacement by a metal (if it where a single replacement by a halogen it would be A + BC
C + BA
CxHy + O2 → CO2 + H2O Combustion of a hydrocarbon
AB → A + B Decomposition
AB + CD → AC + BD Doubl;e replacement
Which reaction types have “subtypes” that require you to use the chart for predicting products? Decomposition and Single
replacement
Describe the characteristics for the five types of reaction that can be used for identifying them.
A reaction with one reactant must be decomposition
A reaction with one product must be Combination
A reaction with a compound whose formula is CxHy and whose products are CO2 and H2O must be: Combustion of a
hydrocarbon
A reaction with two compounds as reactants and products is: Double replacement
A reaction with one element and one compound as reactants is: Single replacement (when the element is not oxygen and
the compound a hydrocarbon)
Identify the five types of reactions
Write the type of reaction for the following chemical reactions
Combination
1.Al + S
Al2S3
Decomposition (binary)
2. Au2O3
Combination
3. H2 + N2
Decomposition (binary)
4. NaF
Au + O2
NH3
Na+ F2
Single replacement by a metal 5. Zn + HNO3
H2
+ Zn(NO3)2
Double replacement
6. LiOH + H2SO4
Li2SO4 + H2O
Single replacement by halogen 7. Cl2 + NaI
Single replacement by metal 8. K
Double replacement
NaCl + I2
+ H2O
KOH + H2
9. AgNO3 + AlCl3
Combustion of a hydroicarbon 10. CH4
AgCl + Al(NO3)3
+ O2
CO2
+ H2O
Identify the subtypes of reaction for decomposition and single replacement
Write the subtype of each reaction below. Use your chart of subtypes to help you.
Decomposition of a metal chlorate
1. KClO3 → KCl + O2
Decomposition of a metal hydroxide
2. NaOH → Na2O + H2O
Single replacement by a halogen
3. Cl2 + CaI2 → CaCl2 + I2
Decomposition of a binary compound
4. CaCl2 → Ca + Cl2
Decomposition of a metal carbonate
5. CaCO3 → CaO + CO2
Single replacement by a metal
6. Zn + AlCl3 → ZnCl2 + Al
Predict the products of a reaction (remembering to use criss-cross and HONClBrIF
Write the products of the following reactions. Indicate the type of reaction as well
1. Decomposition of a binary compound
Au2O3
2. Combination
H2 + N2
3. Single replacement by metal
Zn + HNO3
4. Double replacement
LiOH + H2SO4
5. Single replacement by halogen
Cl2 + NaI
NaCl + I2
6. Combination
Al + N2
AlN3
7. Single replacement
K + H2O
K(OH) + H2
8. Double replacement
AgNO3 + AlCl3
9. Combustion of a hydrocarbon
CH4 + O2
CO2 + H2O
10. Decomposition of metal carbonate
Fe2(CO3)3
Fe2O3 + CO2
11. Single replacement by metal
Cr + H2SO4
Au + O2
H3N more commonly written as NH3
Zn(NO3)2 + H2
Li2(SO4) + H2O
Al(NO3)3
Cl3
Cr(SO4)2 + H2
+ AgCl
Unit 6
Balancing Reactions
Relate the conservation of matter to the rearrangement of atyoms in a chemical formula
Explain what is the purpose of balancing equations
Write and interpret a balanced chemical equation for a reaction, and relate conservation of matter to the
balanced equation
Determine if the following equations are balanced or not
1. CaCO3 → CaO + CO2
2. Al + 3 N2
3.
It is balanced
It is not balanced
AlN3
K + H2O
K(OH) + H2 It is not balanced
Balnce the following reactions
1. 2 KClO3 → 2 KCl + 3 O2
2. 2 NaOH → Na2O + H2O
3.
Cl2 + CaI2 →
CaCl2 + I2
4. 2 NaCl → 2 Na + Cl2
5. 3 Zn + 2 AlCl3 → 3 ZnCl2 + 2 Al
6. 2 Au2O3
7. 3 H2 + N2
4 Au + 3 O2
2 H3N
8. Zn + 2 HNO3
Zn(NO3)2 + H2
9. 2 LiOH + H2SO4
Li2(SO4) + 2 H2O