Download 2nd Nine Weeks Benchmark Study Guide

2nd Nine Weeks Benchmark Study Guide
Unit 1: Scientific Investigations
Safety Symbols: Biohazard
Radiation
Measurement: Force is measured in Newtons using a Spring Scale. Mass is measured in grams using a balance. Volume is measured in
liters using a graduated cylinder. Thermometers measure temperature in degrees Celsius.
Metric Conversions: King Henry Died By Drinking Chocolate Milk = Kilo Hecto Deka Basic Deci Centi Milli
decimal the same direction from where you started to where you are going. 1200 meters = 1.2 kilometers
(Move the
Scientific Notation: 100,000,000 = 1.0 x 108 ( count the zeros) You move the decimal between the first and second number. You then
remove all zeroes and the exponent is the number of places the decimal was moved.
Scientific Method: Problem Research Hypothesis Experiment Data Conclusion
Hypothesis: educated guess about a possible outcome to an experiment. The independent variable in an experiment is what is being
tested or controlled by the experimenter. The dependent variable is the results. The constants are the variables that are kept the same
and the control is what the independent variable is
being compared to.
Data: We can collect data through observations. Qualitative observations are descriptive and quantitative observations are numerical.
Unit 2: Physical and Chemical Properties/Changes
Physical properties describe a substances appearance or measurement: luster (shiny or dull), boiling point, melting point, malleable
(hammered into sheets/bent/shaped), ductile(drawn into a wire), color, texture, solubility (dissolve), density (mass/volume), odor
A physical change does not change the composition of a substance, only the shape or size. Examples: tearing paper, change of state
(liquid to solid, gas to liquid)
Chemical properties describe a substances ability to change into a new substance: flammability (burn), combustibility (explode),
reactivity, and acidity. Combustibility happens when a substance reacts rapidly with oxygen and gives off heat.
A chemical change is when a chemical reaction takes place and a new substance is formed. Examples: digesting food, respiration,
burning, cooking, rust, tarnish, food spoiling
Unit 3: States of Matter
Particle theory of matter says that all matter is made up of atoms that are in constant motion. The temperature at which all molecular
motion stops is called Absolute zero or 0 Kelvin (K). This could never happen. Particles in a solid are rigid and vibrate in place. They
have a definite mass and a definite volume. They are strongly attracted to one another. Particles in a liquid slide past each other and
have some attraction to one another. They take the space of the container filling the bottom first due to gravity. They have a define
volume but not definite shape. Particles in a gas float freely and have no attraction to one another. They have not definite volume or
mass. Plasma is the most common in the universe and makes up stars, lightning bolts, and auroras. The particles in plasma float freely
but are electrically charged with no definite mass or volume.
Solid to liquid = melting, liquid to gas = vaporization, gas to liquid= condensation, liquid to solid= freezing, solid to gas= sublimation.
An example of sublimation is frozen CO2 (Dry Ice).
The freezing point of water is 0 degrees Celsius and the boiling point is 100 degrees Celsius. The warmer a substance is, the faster the
particles move and the more energy the substance has. The temperature remains the same during a phase change.
Exothermic reactions releases heat energy and cool down: freezing and condensation
Endothermic reactions absorbs energy and warm up: melting and vaporization, and sublimation
Unit 4: Elements, Compounds, and Mixtures
Elements: Cannot be broken down by physical or chemical means only nuclear. They are represented by a chemical symbol (only 1
capital letter) They are found on the periodic table in three different categories: Metals, Non-Metals and Metalloids. Metals are on the
left side of the periodic table and their properties include: malleable(shaped/bent), ductile(drawn into a wire) shiny, and good
conductors. Non-Metals are on the right side of the periodic table and their properties include: brittle(break easily) dull, poor conductors,
and most are a gas at room temperature. Metalloids are along the zigzag or stair step line of the periodic table and their properties
include: semiconductors and have properties of both metals and nonmetals.
Compounds: Composed of 2 or more elements chemically combined in a fixed ratio. The properties of compounds are different than the
elements that formed them. Organic compounds contain the element Carbon (C) They are represented by a chemical formula (2 or more
capital letters)
Mixtures: Composed of 2 or more substances physically combined. Each component keeps their properties. There are three different
types of mixtures: Solutions, Suspensions, and Colloids. Solutions are homogeneous and appear to be one substance that has a solute
(smaller amount) dissolved into a solvent (larger amount). Examples: Kool Aid, Lemonade, Saltwater, and Air. Suspensions are
heterogeneous and have particles that are large enough that they settle out. Examples: Italian dressing, muddy water, and snow globe.
Colloids have properties of both solutions and suspensions. The particles do not settle out but will scatter a light beam. Examples:
Mayonnaise, milk, fog, jello, and whip cream.
Water is the universal solvent. Solutes dissolve faster by mixing/stirring, heating, or crushing.
Unit 5: Atomic Structure
Scientists: Democritus coined the term atomos: uncuttable. He said all things are made up of atoms. Dalton wrote the atomic theory and
said that atoms of one element are the same but different than atoms of another element. Thomson used cathode rays to discover the
electron and created the Plum Pudding Model. Rutherford used Gold foil to discover a small, dense, positive nucleus. He said that most of
the atoms is mostly empty space. Bohr said that the electrons traveled in fixed paths around the nucleus. He worked with Chadwick who
discovered the neutron. The Bohr model shows protons and neutrons in the nucleus and electrons traveling in orbitals. This model is still
used today for 2D diagrams. Our most current understanding is the Electron Cloud Model. In this model the protons and neutrons are
located in the nucleus and the electrons are in clouds around the nucleus showing that most of the atom is empty space. Another name
for this is Quantum Mechanics.
Parts of an atom: An atom is the smallest form of matter. Protons are positive and are inside the nucleus. Neutrons are neutral and
inside the nucleus. Electrons are negative and outside the nucleus. Protons determine the element. Atoms that have a different number
of neutrons are called an isotope. Most of the mass of an atom comes from the nucleus. The mass number is the number of protons and
neutrons in an atoms nucleus and represented by an atomic mass unit (amu). An atom with no overall charge would have equal numbers
of protons and electrons.
Unit 6: Periodic Table
Mendeleev arranged the elements on the periodic table in order of increasing atomic mass. Moseley rearranged the elements by
increasing atomic number. Each element has a unique atomic number which is the number of protons in the nucleus. We can also find
out the elements chemical symbol, name, and atomic mass by looking on the periodic table. The most abundant element in the universe
is hydrogen.
The periodic table has 7 periods (rows) and 18 groups/families (columns). Elements in groups/families often share similar properties
because their atoms have the same number of electrons in their outer energy level. Atoms of elements in Groups 1 and 2 have the same
number of electrons in their outer energy level as their group number. Atoms of elements in Groups 3-12 have no general rule relating
their electrons in their outer energy level to their group number. Atoms of elements in Groups 13-18 have 10 fewer electrons in their
outer energy level than their group number.
The zigzag line on the periodic table helps you identify elements as metals, nonmetals, and metalloids. Most of the elements on the
periodic table are metals. The nonmetals are located in the top right corner of the periodic table and are mostly gas at room
temperature.
Alkali Metals are the most reactive metals. The metals become less reactive as you move across the periodic table. Halogens are the
most reactive nonmetals because they only gain one electron to have a complete outer level. Noble Gases are the least reactive group
because they have a complete set of electrons in their outer shell.
Unit 7: Chemical Bonding
Atoms bond by gaining, losing, or sharing electrons to have a filled outermost energy level with 8 valence electrons. The
group numbers tell how many electrons are in the outer energy level of an atom of the element. Helium is the exception to
the rule. Its outermost energy level is full with only 2 valence electrons in the first energy level. Group 18, Noble Gases, do
not usually form bonds because they already have a full set of valence electrons in their outermost energy level.
There are four types of bonds: Ionic, Covalent, Atomic and Metallic. Ionic bonds are formed when atoms lose or gain
electrons; they form ions (charged atoms). The number of protons stays the same. Ionic bonds form between a metal and a
nonmetal. Metals tend to lose electrons because they have so few, this makes them become positive ions. Nonmetals tend
to gain electrons so they become negative ions. Covalent bonds are formed when atoms share electrons; they form
molecules that are neutral. Covalent bonds are formed between two nonmetals. Metallic bonds are formed from
positively charged ions that are attracted to the electrons. This gives metals their unique properties and occurs between
two metals. Atomic bonds are formed when two atoms of the same element bond together to form a diatomic molecule.
Unit 8: Chemical Reactions
Parts of an equation: The left side of an equation is the reactants. The right side is the products. The large number that is
in front of a chemical formula is called the coefficient. The coefficient tells the number of molecules and you find this by
multiplying. The small number that is behind an elements chemical symbol is the subscript. This tells the number of atoms
for each element in a chemical formula.
Balancing chemical equations: Count the number of atoms of each element on both sides of the equation. Add a
coefficient to the compounds in the equation so that it is equal on both sides. We balance chemical equations because the
Law of Conservation of Matter says that matter cannot be created or destroyed, only transferred. Sometimes a gas is
formed during a chemical reaction and escapes.
Types of Reactions: Synthesis reactions are two simple substances forming a more complex substance. (No plus sign on the
right) Decomposition is a complex compound breaking down into two simpler substances. (No plus sign on the left) Single
Displacement reactions have an element that is by itself on both sides of the equation. Double displacement reactions have
2 or more large compounds on both sides of the equation.
Combustion reactions: take in oxygen and produce water(H2O) and carbon dioxide (CO2). Combustion reactions release
energy and are exothermic reactions. Respiration is an example of a combustion/exothermic reaction. Photosynthesis is
the opposite of respiration and is an endothermic reaction.
Unit 9: Acid and Base
Properties of Acids: H+ ions, turns blue litmus paper red, and has a pH less than 7. Tastes sour, corrodes metal, and
conducts electricity. (Foods)
Properties of Bases: OH- ions, turns red litmus paper blue, and has a pH greater than 7. Tastes bitter, slippery, corrodes
skin and organic substances, and conducts electricity. (Cleaners)
Neutral: salt and water are neutral at a pH of 7. When an acid and a base of the same strength are combined a salt or water
is formed.