This document provides a chemistry course review covering several key topics: 1. Laboratory safety rules including proper use of goggles, handling of chemicals, heating test tubes, and responding to alarms. 2. Metric units and tools used to measure length, volume, mass, and temperature. Precision measures consistency while accuracy measures proximity to true values. 3. Atomic structure including electron configurations, ions, isotopes, and historical atomic models. Radioactivity, half-life, and types of radiation are also addressed.

1. Chemistry I Course Review Key
The Basics
1.a) Goggles must be worn any time there is an open flame or hazardous chemicals in the lab.
b) Chemicals should be handled with care; lids should be returned when a bottle is finished;
chemicals should never be eaten or tasted unless directed by the teacher. Students should
pour form larger stock bottles into smaller containers that will be used in the lab. Any
leftover waster should be disposed of according to teacher direction, but NEVER poured
back into the stock solution.
c) When heating a chemical in a test tube, the open end of the test tube should be aimed towards a
wall, away from any people.
d) Report cuts and burns to a teacher immediately who will start first aid if necessary and contact
the health room.
e) If an odor is to be detected, the fumes should be wafted towards the nose, not snorted in a large
amount.
f) If a fire alarm sounds during lab, all electrical equipment, water, and gas should be shut off
before the room is evacuated as normal.
2. a)Football fields can be measured in meters. A paperclip can be measured in cm. Length should
best be measured with a metric ruler or meter stick.
b) The volume of a bottle of soda could be measured in liters (2L soda) or mL (20oz size) with a
graduated cylinder. Raindrops can be measured using a graduated cylinder mL A
rectangular solid can be measured with a metric ruler.
c) The mass of a human being would be measured in kilograms on a balance. A penny would also
be measured on a balance however it would be measured in grams.
d) Temperature should best be measured with a thermometer.
3. a) 80.2 c) 1.3 x 106 e) 0.01628
b) 2.41.3 x 1023 d) 1.8 x 106 f) 0.0012
4. a) kilo- b) hecto- f) milli-
c) deka-
d) deci-
e) centi-
5. a) 0.0045 kg c) 5.4 x 105 mL e) 3.25 x 10-4 mm
b) 8.5 x 105 mm d) 0.64512 L
6. Precision is how close a group of measurements are to each other; accuracy is how close a
measurement is to the accepted or true value.
The Atom
7. a) Each shell (energy level) would hold 2,8,18,32 electrons respectively. Each subshell would hold
s(2), p(6), d(10), f(14).
b) i) 1s22s22p63s1 ; Lewis Dot Structure (LDS) is Na with a single dot.
ii) 1s22s22p3 ; LDS is N with one pair of dots and three single dots.

2. iii) 1s22s22p63s23p64s23d104p5 ; LDS is Br with a single dot and three pairs.
c) An ion is a atom or molecule with an overall positive or negative charge.
d) A sodium atom becomes an ion by losing its single outer shell electron. It would therefore have a
positive one (+1) charge.
e) A sulfur atom becomes an ion by gaining two electrons to complete its outer shell. It would
therefore have a negative two (-2) charge.
f) Carbon-14 has 6 protons, 6 electrons and 8 neutrons.
g) U-238 has 146 neutrons.
h) Dalton’s model consisted of solid spheres of matter. Thomson’s model had a ball of positively
charged matter with negatively charged “bits” inside of it. Rutherford/Bohr’s model had a dense
positive core (the nucleus) with electrons in perfect circular orbits around it. Schrodinger’s
model had a dense positive core with electrons orbiting in orbitals (three-dimensional,
mathematically-defined zones of space).
8. a) Natural radioactivity is radiation that exists on its own in nature. Induced radioactivity is radiation
that has been created in a laboratory (man-made).
b) The three basic types of radiation are: alpha (α ) in which a helium nucleus (alpha particle) breaks
off from the unstable atom; beta (β) in which an electron produced from the preakup of a neutron
(a beta particle) is shot from the nucleus; and gamma (γ) in which a birst of high energy light ( a
gamma ray) is emitted from the nucleus.
c) Penetrating ability: least is alpha, then beta, and gamma has the most.
d) Fission is when a large unstable nucleus splits into two new nuclei. Fusion is when two smaller
nuclei are fused together to make a single nucleus.
e) An isotope is a group of elements with the same number of protons (same element) and the same
number of neutrons (same mass).
f) Half-life is the time it takes for half of a radioactive sample to decay.
g) 8.52 x 10-27 g
h) 52.00 amu
The Periodic Table
9.a) The periodic table is arranged such that the elements are in order of increasing atomic number, and
elements of similar chemical properties are grouped in columns together. This is different than
Mendeleev’s table which was organized by atomic mass.
b) A group is a vertical column on the periodic table, containing elements of similar chemical properties.
A period is a horizontal row on the periodic table.
c) The metals are to the left and below the “stair-step” on the periodic table. The nonmetals are to the
right and above.
d) Metals: shiny; good conductors of heat & electricity; malleable & ductile
Nonmetals: dull; insulators of heat & electricity; brittle
Metalloids: elements with some metal properties and some nonmetal properties.
e) Group 1: alkali metals ; Group 2: alkaline earth metals ; Group 17: halogens ; Group 18: noble
gases ; Groups 3-12: transition metals
f) Ionization energy is the amount of energy required to remove the outer most electron from an
atom. Electronegativity is a measure of an atom’s ability to draw electrons towards itself in a
covalent bond.

3. g) Electronegativity increases across a period and decreases down a family. Ionization energy does
the same thing.
h) Elements in a family have similar chemical properties.
i) Atomic radius decreases across a period and increases down a family.
j) V has the highest ionization energy.
k) Fr is the most metallic of all the elements. It has the lowest ionization energy, the lowest
electronegativity, and is the most reactive metal. It has the largest atomic radius. F is the most
non-metallic of all the elements. It has the highest ionization energy and the highest
electronegativity and is the most reactive non-metal. These two elects are the “most” of their
group (metal versus non-metal).
l) Even though both Be and He have two outer shell electrons, Heliums electrons fill the first energy
level (shell) completely while Be has two more electrons that are in the next subshell causing an
incomplete outermost shell.
Compounds and Bonding
10. a) An ionic bond is the electrostatic attraction between two oppositely charged ions. A covalent
bond is a shared pair(s) of electrons between two atoms. They are different chiefly in that an
ionic bond doesn’t need to exist in order for the atoms to have a complete outer shell (they
already have transferred electrons) but a covalent bond must stay whole for all of the atoms to
keep their stable full outer shells.
b) Metallic bonds are bonds that occurs the result of free floating valence electrons for positively
charged metal ions. Metallic bonds help explain why metals conduct heat and electricity so
easily as the heat (increased motion) moves easily from one electron to another.
c) i) potassium sulfate iv) tin(IV) nitrate
ii) aluminum chloride hexahydrate v) carbon monoxide
iii) hydrobromic acid vi) nitrous acid
d) i) Ag3PO4 iv) K2CrO4
ii) CCl4 v) Cu(NO3)2•3H2O
iii) Fe2O3 vi) H2SO4
e) A roman numeral in a chemical’s name tells the charge on the positive ion (ex: “iron(III)
oxide” means that the iron ion’s charge is +3).
f) i) ii) iii)
g) i) linear ii) tetrahedral iii) bent
Matter and Energy
11. a) 4650 J
b) 360 g (358.5 g rounded to two sig figs)
c) Copper would be heated faster than water of the same mass from room temp to 56 ºC because
metals (like copper) have smaller specific heats that water does, so it takes less energy (and
therefore less time) to heat them.
d) Heat of fusion is the amount of heat energy needed to melt 1 g of a substance. Heat of
vaporization is the amount of heat energy needed to vaporize 1 g of a substance.

4. e) 4540 J (4536 J rounded to 3 sig figs)
f) Temperature is the average kinetic energy of all the particles in a sample. Absolute zero is the
theoretical lowest temperature possible (O K).
g) Temperature is an average kinetic energy of the particles, where heat is the total kinetic energy
of the particles.
h) i) endothermic ii) endothermic iii) exothermiciv) exothermic
i) Intensive properties are ones that do not depend on the size of the sample (ex: density,
freezing point) while extensive properties are ones that do depend on the size of the sample (ex:
mass, volume).
j) Salt and sand could be separated by dissolving the salt in water, filtering out the sand, then
boiling the water away from the salt. Alcohol and water could be separated by distillation (boiling
the alcohol away form the water and collecting and recondensing the vapors).
The Mole
12. a) i) 110.26 g/mol ii) 253 g/mol iii) 342.3 g/mol
b) i) 29.1 % K ; ii) 25.3% K iii) 28.1% K
c) i) 0.136 mol K2S ii) 0.0593 mol Ba(SCN)2 iii) 0.0438 mol Al2(SO4)3
d) 3.39 x 1024 molecules O2
e) 126 L O2
f) Sn3N2
Chemical Reactions
14. a) i) 2, 2, 2, 1 ii) 2, 2, 3 iii) 1, 6, 2, 3
b) i) single replacement ii) decomposition iii) double replacement (ionic)
c) i) zinc + copper(II) sulfate —> copper + zinc sulfate
Zn + CuSO4 —> Cu + ZnSO4
i) lead(II) nitrate + sodium sulfate —> sodium nitrate + lead(II) sulfate
Pb(NO3)2 + Na2SO4 —> 2 NaNO3 + PbSO4
ii) ethane + oxygen —> carbon dioxide + water
2 C2H6 + 7 O2 —> 4 CO2 + 6 H2O
Stoichiometry
15. a) i) 10 mol NaCl ii) 5 formula units Na2SO4
b) i) 9 molecules CO2 ii) 25 mol O2 iii) 13 L CO2
c) 24.9 g MgO
d) 4.3 g Al2O3
e) 22.8 g PbI2 ; lead(II) nitrate is the limiting reactant
Acids, Bases, and Salts
16. a) i) S ii) A iii) B iv) A v) B vi) B vii) S viii) S
b) A solution’s acidity (or basicity) can be generally tested by litmus paper (litmus turning red
indicates an acid, litmus turning blue indicates a base). More specifically, pH paper (or a pH
meter) can be used to determine the solution’s pH (pH below 7 is acidic, above 7 is basic).
c) A strong acid ionizes 100% in water. A weak acid ionizes less than 100%.

5. d) When an acid and a base react, the reaction is called a neutralization reaction, and the products
will be water and a salt.
Gas Laws
17. a) Pressure is the force applied per unit area.
b) At constant pressure, temperature and volume are directly proportional (if one goes up the
other goes up). This is Charles’s Law.
c) At constant temperature, pressure and volume are inversely proportional (if one goes up the
other goes down). This is Boyle’s Law.
d) A constant volume, pressure and temperature are directly proportional (if one goes up the
other goes up). This is Gay-Lussac’s Law.
e) PV = nRT
f) V2 = 1.10 L
g) V2 = 0.549 L
h) T2 = 526 K
Solutions
18. a) A solution is a homogeneous mixture. A solute is the substance being dissolved in a solution. A
solvent is the substance that does the dissolving. In salt water, salt is the solute and water is the
solvent.
b) To make a solid dissolve faster in a liquid you could: stir the mixture ; heat the mixture ; grind up
the solid into smaller pieces.
c) Molarity measures the concentration of a solution; specifically it measures the number of moles of
solute in every liter of solution. It’s units are “molar”, M, or mol/L.
d) 2.5 M CuSO4
e) 4.28 M NaCl
f) 2 mol CaCl2 (1.75 mol rounded to 1 sig fig)
g) Solutions that are high in electrolytes will conduct electricity. If a solution does not contain
dissolved ions then it will not conduct electricity. Molten ionic compounds (which may not be
true solutions) will also conduct electricity.