Welcome! to Chemistry!
Name ________________________Date__________ Period ____
Chemistry Final Exam Review
Write all answers to questions on a separate sheet of paper.
Properties of Matter
Physical Properties of Matter
Do not change the identity of the substance.
Chemical Properties
The potential to cause a
chemical reaction.
mass
volume
density
(mass per
volume)
melting point
conductivity
color
malleability
(metals)
ductility
(metals)
boiling point
luster
reactivity
oxidation
flammability
Chemical and Physical Changes
1) A chemical change occurs when something new is made. Words associated with this type of changes are:
rotting, decomposing, burning, digestion, rusting.
2) A physical change occurs when nothing new has been made. Words associated with this type of changes
are: tearing, cutting, painting.
Evidence of a chemical change:
Precipitate formed
Evolution of gas (bubbles)
Color change
Energy change (energy given off or absorbed)
Atomic Structure
Proton – positive charge
Neutron – neutral charge
Electron – negative charge
Atomic number = number of
protons.
Mass number = number of
protons and neutrons in the
nucleus of an atom.
Number of neutrons = mass
number minus number of
atomic number.
Protons and neutrons are found in the nucleus of an atom.
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Metals Nonmetals
solid (with the exception of Hg, a liquid).
shiny, good conductors of electricity and
heat.
ductile (they can be drawn into thin wires).
malleable (they can be easily hammered
into very thin sheets).
good conductor of heat and electricity
lose electrons to combine with other
elements
not solid (with the exception Hg, a liquid).
shiny, good conductors of electricity and
heat.
ductile (they can be drawn into thin wires).
malleable (they can be easily hammered
into very thin sheets).
good conductor of heat and electricity
lose electrons to combine with other
elements
Periodic Table
3) Metals are found on what side of the periodic table? Left of the zigzag line
4) Nonmetals are found on what side of the periodic table? Right of the zigzag line
5) Where are the metalloids located? Adjacent to the zigzag line
6) What is the group number of the alkali metals? Group IA
7) What is the group number of the alkaline earth metals? Group IIA
8) What is the group number of the halogens? Group VA
9) What is the group number of the noble gases? Group VIIA
10) The noble gases are chemically non-reactive (do not combine with other elements). Why? Noble gases
have 8 valence electrons. The outermost energy level is filled.
Periodic Trends
Electronegativity is a measure of an atom's ability to attract electrons to itself.
11) Which atom in each pair has the larger atomic radius?
a) Li or K* b) Ca* or Ni c) Ga* or B d) O or C* e) Cl or Br* f) Be or Ba* g) Si* or S
h) Fe* or Au
12) What is the periodic trend for atomic size from top to bottom in a group? from left to right in a period?
Atomic radius increases top to bottom. Atomic radius decreases left to right.
13) Which element in each pair has a higher electronegativity value?
a) Cl, F* b) C, N* c) Mg*, Ne d) As*, Ca
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Dalton’s Atomic Theory
All matter composed of atoms.
All atoms of an element are identical.
Atoms cannot be divided, created, or destroyed.
We now know:
Atoms can be divided into smaller particles.
Atoms of the same element can have different masses.
Electron configurations
Electron configuration - the arrangement of electrons in an atom around the nucleus of atoms. Electrons are
not placed at fixed positions in atoms, but we can predict approximate positions of them. These positions are
called energy levels of atoms.
Energy level n=1, 2, 3, 4, 5, 6, 7
Sublevels s, p, d, f
s has 1 orbital
p has 3 orbitals
d has 5 orbitals
f has 7 orbitals
Each orbital can hold at most 2 electrons.
Example
Chlorine 17 e-
1s2 2s2 2p6 3s2 3p5
14) Write long-hand and short-hand electron configurations with orbital notation for each of the following
elements.
A. nitrogen B. iodine C. calcium D. barium E. copper
A. 7e- 1s2 2s2 2p3
B. 53e- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5 I 53e- [Kr] 5s2 4d10 5p5
C. 20e- 1s2 2s2 2p6 3s2 3p6 4s2 Ca 20e- [Ar] 4s2
D. 56e- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 Ba 56e- [Xe] 6s2
Ions are formed from the gain or loss of electrons. Metals lose electrons to form cations, positive ions.
Nonmetals gain electrons to form anions, negative ions.
15) For each of the following elements, state whether the element will form cations or anions and the
number of electrons gained or loss.
F. Potassium G. Bromine H. Strontium I. Sulfur J. Aluminum
Element Electrons gained Electrons lost cation or anion
K 1 cation
Br 1 anion
Sr 2 cation
S 2 anion
Al 3 cation
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Chemical Bonding
An ionic bond is formed from the transfer of electrons between a metal and a nonmetal.
A covalent bond is formed from the sharing of electrons between a nonmetal and a nonmetal.
16) Classify each of the following compounds as ionic or covalent. Write the name of each compound.
A. NO2 B. MgBr2 C. N2O3 D. SO2 E. CaO F. CuCl2 G. Fe2O3 H. NaCl I. O2
covalent ionic covalent covalent ionic ionic ionic ionic covalent
Law of Conservation of Matter
The Law of Conservation of Matter states:
matter is neither created not destroyed in a chemical reaction.
the mass and number of atoms of the products of a reaction must equal the mass and number of
atoms of the reactants.
17) Which of the following questions obey the Law of Conservation of Matter? Circle your answers.
A. NH4F + AlCl3 → NH4Cl + AlF3
B. **3 Na2CO3 + 2 H3PO4 → 2 Na3PO4 + 3 H2O + 3 CO2
C. **Mg + Co(NO2)2 → Mg(NO2)2 + Co
D. **H2SO4 + 2 NaOH → 1 Na2SO4 + 2 H2O
E. C4H8O + 11 O2 → CO2 + H2O
F. **AgMnO4 + Sr → Ag + SrMnO4
G. 2 LiBr + 1 H2SO4 → 1 LiHSO4 + 2 HBr
Types of Reactions
Synthesis reaction = one product
Decomposition reaction = one reactant
Single replacement reaction = one element replaces another element in a compound
Double replacement reactions = the two reactants are ionic compounds. The positive ions trade partners.
Combustion reaction = a hydrocarbon compound reacts with oxygen to produce water and carbon dioxide.
Neutralization reaction = an acid reacts with a base to produce a salt and water
18) State the type of each reaction. Then balance the equations.
A. Decomposition 2HgO 2 Hg + O2
B. Single replacement 2Al + 3Pb(NO3)2 2 Al(NO3)3 + 3Pb
C. Double replacement 2 AgNO3 + K2SO4 Ag2SO4 + 2 KNO3
D. Combustion 2CH3OH + 3O2 2CO2 + 4H2O
E. Double replacement Zn(OH)2 + 2HNO3
Zn(NO3)2 + 2 H2O
F. Decomposition 2 H2O 2H2 + O2
G. Single replacement Cu + 2AgNO3 Cu(NO3)2 + 2Ag
H. Synthesis N2 + 2H2O NH4NO2
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Percent Composition % = part/whole x 100
19) Calculate the percent composition for each of the following compounds.
A. hydrochloric acid HCl
H 1 x 1g = 1g
Cl 1 x 35g = 35g
36g
1gH/36g HCl x 100 = 2.78% H
35gCl/36g x 100 = 97.22% Cl
B. sulfuric acid H2SO4
H 2 x 1g = 2g
S 1 x 32g = 32g
O 4 x 16g = 64g
98g
2g H/98g H2SO4 x 100 = 2.04% H
32g S/98g H2SO4 x 100 = 32.65% S
64g O/98g H2SO4 x 100 = 65.31% O
C. nitric acid HNO3
H 1 x 1g = 1g
N 1 x 14g = 14g
O 3 x 16g = 48g
63g
1g H/63g HNO3 x 100 = 1.59% H
14g N/63g HNO3 x 100 = 22.22% N
48g O/63g HNO3 x 100 = 76.19% O
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Empirical and Molecular Formulas
Molecular
Formula
Empirical
Formula
H2O H2O
CH3COOH CH2O
CH2O CH2O
C6H12O6 CH2O
Empirical Formula - the formula of a compound expressed
as the smallest possible whole-number ratio of subscripts of
the elements in the formula.
Molecular Formula - the formula of a compound in which
the subscripts give the actual number of each element in the
formula.
The molecular formula and the empirical formula can be identical.
20) Write the empirical formulas for the following compounds.
A. A compound is found to have (by mass) 48.38% carbon, 8.12% hydrogen and oxygen.
What is its empirical formula?
48.38g C 1 mol C
=
4.032 mol C
= 1.14 Empirical Formula C1H2O1
12 g C 3.53
8.12g H 1 mol H
=
8.12 mol H
= 2.3
1 g H 3.53
56.50 g O 1 mol O
=
3.53 mol O
= 1
16 g O 3.53
B. A compound is known to have an empirical formula of CH and a molar mass of 78.11 g/mol.
What is its molecular formula?
Molar mass CH = 13 g/mol 78.11g/13g = 6 Molecular Formula C6H6
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Mole Calculations
1 mole = the molar mass of the substance 1 mole = 6.02 x 1023 atoms, ions, molecules
21) Make the following mole calculations.
A. Calculate the mass of 2.50 moles of aluminum hydroxide.
2.50 mol Al(OH)3 1 mol Al(OH)3
= 0.03 mol Al(OH)3
78 g Al(OH)3
B. Calculate the mass of 0.0125 moles of dinitrogen pentoxide.
0.0125 moles N2O5 108 g N2O5
= 1.35 g N2O5
1 mol N2O5
C. Calculate the mass of 3.12 x 1021 ions of iron (III) sulfide
3.12 x 1021 ions Fe2S3 1 mol Fe2S3 208 g Fe2S3
= 1.078 g Fe2S3
6.02 x 1023 Fe2S3 1 mol Fe2S3
D. Calculate the mass of 4.30 x 1027 molecules of carbon monoxide gas.
4.30 x 1027 mlc CO 1 mol CO 28 g CO
= 2.00 x 105 g CO
6.02 x 1023 CO 1 mol CO
E. Calculate the number of moles in 1.25 grams of strontium nitrate.
1.25 g Sr(NO3)2 1 mol Sr(NO3)2
= 0.006 mol Sr(NO3)2
212 g Sr(NO3)2
F. Calculate the number of moles in 0.570 g of chlorine gas.
0.570 g Cl2 1 mol Cl2
= 0.008 mol Cl2
70 g Cl2
G. How many ions are in 225 g of lithium oxide?
225 g Li2O 1 mol Li2O 6.02 x 1023 Li2O
= 4.52 x 1024 Li2O
30 g Li2O 1 mol Li2O
H. How many molecules are in 15.0 g of silicon tetrafluoride?
15.0g SiF4 1 mol SiF4 6.02 x 1023 mlc SiF4
= 8.68 x 1022 mlc SiF4
104g SiF4 1 mol SiF4
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Stoichiometry
Stoichiometry is the relationship between the relative quantities of substances taking part in a reaction or
forming a compound.
22) Make the following calculations.
A. N2 + 3H2 2NH3
How many moles of NH3 at STP is produced if 25.0 g of N2 is reacted with an excess of H2?
25.0 g N2 1 mol N2 2 mol NH3
=
28 g N2 1 mol N2
B. 2KClO3 2KCl + 3O2
If 5.0g of KClO3 is decomposed, how many moles of O2 is produced at STP?
5.0 g KClO3 1 mol KClO3 3 mol O2
= 0.123 mol O2
122 g KClO3 2mol KClO3
C. H2SO4 + 2NaOH 2H2O + Na2SO4
How many molecules of water are produced if 2.0g of sodium sulfate are produced in the above
reaction?
2.0 g Na2SO4 1 mol Na2SO4 2 mol H2O 6.02 x 1023 mlc H2O
= mol H2O
142 g Na2SO4 1 mol Na2SO4 1 mol H2O
D. H2SO4 + NaOH Na2SO4 + H2O
If 30.0 g of H2SO4 reacts with sodium hydroxide, what mass of water is produced?
30.0 g H2SO4 1 mol H2SO4 1 mol H2O 18 g H2O
= 5.5 g H2O
98 g H2SO4 1 mol H2SO4 1 mol H2O
Gases
Absolute zero - lowest theoretical temperature, all particle motion would stop.
Absolute zero = 0 Kelvin = -273o C __
o
C + 273 = __ K
Boyle’s Law – V1P1 = V2P2
Charles Law
V1
=
V2
Combined Gas Law
V1P1
=
V2P2
T1 T2 T1 T2
Ideal Gas Law PV = nRT Universal Gas Constant 0.0821 L • atm
mol • K
23) Make the following calculations.
A. A gas occupies 3.5L at 2.5 mm Hg pressure. What is the volume at 10 mm Hg at the same
temperature?
Boyle’s Law – V1P1 = V2P2
3.5 L x 2.5 mm Hg = V2 x 10 mm Hg
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B. A constant volume of oxygen is heated from 100C to 185C. The initial pressure is 4.1 atm. What is
the final pressure?
G-L Law
(Combined Gas Law)
V1P1
=
V2P2 4.1 atm P2
= 5.034 atm
T1 T2 373 K 458 K
C. An ideal gas occupies 400ml at 270 mm Hg and 65C. If the pressure is changed to 1.4 atm and the
temperature is increased to 100C, what is the new volume?
G-L Law
(Combined Gas Law)
V1P1
=
V2P2 (400 mL)( 0.355 atm)
=
(V2)( 1.4 atm) = 111.93
T1 T2 338 K 373 K mL
D. What is the pressure of 23g of neon gas at 1C and a volume of 2L?
Ideal Gas Law PV = nRT
23.0 g Ne 1 mol Ne
= 1.15 mol Ne
20 g Ne
P =
(2 L) (1.15 mol) (0.0821 L • atm)
(274 K) (mol • K)
E. A 600mL balloon is filled with helium at 700mm Hg barometric pressure. The balloon is released
and climbs to an altitude where the barometric pressure is 400mm Hg. What will the volume of the
balloon be if, during the ascent, the temperature drops from 24 to 5C?
G-L Law
(Combined
Gas Law)
V1P1
=
V2P2 (600 mL)( 700mm Hg)
=
(V2)( 400mm Hg)
T1 T2 297 K 278 K = 982.83 mL
F. A 500 mL metal cylinder holding 0.100 moles of helium gas is known to rupture at a pressure of 10
atmospheres. At what temperature, in °C, will the container fail?
Properties of Water
Polarity is the unequal sharing of electrons within the water molecule between the hydrogens and the
oxygen. The oxygen end of the molecule is slightly negative. The hydrogen end slightly positive. Water is
known as the universal solvent because of its polarity.
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Solutions, Molarity, Dilutions
Molarity – a measure of concentration in moles per liter
Molarity =
moles Solution = solute + solvent
liters
24) Calculate the molarity of each of the following. *Volumes must be in Liters.
A. What is the molarity of a solution that contains 1.724 moles of H2SO4 in 2.50 L of solution?
0.690 M H2SO4 =
1.724 moles
2.5 L
B. What is the molarity of a solution prepared by dissolving 25.0 g of HCl (g) in enough water to make
150.0 mL of solution?
0.694 mol
= 4.63 M HCl
0.150 L
C. How many grams of potassium carbonate are needed to make 200 mL of a 2. 5 M solution?
2.5 M K2CO3 =
x mol x = 0.5 mol
0.200 L
D. What is the concentration of a solution with a volume of 2.5 L containing 60 moles calcium
phosphate?
24 M Ca3(PO4)2 =
60 moles
2.5 L
Dilutions
Mc x Vc = Md x Vd M1 x V1 = M2 x V2
25) Make the following calculations.
A. If you add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the
dilution be? (0.15 M) (0.125 L) = (0.150 L) (Md)
B. If 45 mL of water are added to 250 mL of a 0.75 M K2SO4 solution, what will the molarity of the diluted
solution be? (0.75 M) (0.250 L) = (0.295 L) (Md)
C. How much 0.075 M NaCl solution can be made by diluting 450 mL of 9.0 M NaCl?
(9.0 M) (0.450 L) = (0.075 M) (Vd)
Solubility is the maximum amount of a substance that will dissolve in a given amount of solvent at a
specific temperature.
Insoluble compounds form a precipitate.
Saturated solution – a solution that contains the maximum amount of solute at a given temperature.
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Factors that increase the solubility of a solid in a
liquid.
Factors that increase the solubility of a gas in a
liquid.
Nature of the solute and solvent
Temperature increase. (There are exceptions.)
Size of the particles.
Stirring, agitation.
Amount of solute already in the solution.
Temperature decrease.
Pressure increase.
Electrolytes and Nonelectrolytes
An electrolyte is a chemical compound that dissociates into ions in water. Capable of conducting electricity.
Ionic compounds are electrolytes. examples: NaCl, KI, Ca(OH)2
A nonelectrolyte is a chemical compound that does not dissociate in water. Not capable of conducting
electricity.
Covalent compounds are nonelectrolytes. examples: CO2, N2O3, SO2
26) During lab a student made the following observations. Which of the following groups of substances
contains only electrolytes?
Substance Observations
A. CH3OH and CCl4
HCl Bright light
B. HCl, MgCl2 and CCl4
CH3OH No light
C. CH3OH, NaOH and CH3COOH
MgCl2 Some light
D. **HCl, MgCl2, NaOH and CH3COOH
NaOH Bright light
CH3COOH Some light
CCl4 No light
Acids and Bases
Characteristics of Acids Characteristics of Bases
Taste sour
pH less than 7
Acids effects indicators:
o Acids turn blue litmus to red
o Phenolphthalein is colorless
[H+ ] > [OH-]
Electrolytes
React with metals to produce H2
Taste bitter
pH greater than 7
Bases effect indicators:
o Bases turn red litmus blue
o Phenolphthalein is pink-purple
[OH-] > [H+ ]
Electrolytes
Feel slippery
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pH – A measure of hydrogen concentration.
Neutralization Reaction
Acid + Base
a Salt + water example HCl + NaOH
NaCl + H2O
Neutralization reactions are also double replacement reactions.
27) Predict the products for each of the following types of reactions. Write a complete balanced equation for
each reaction.
A. Ca(OH)2 + H3PO4
Ca3(PO4) + H2O
B. HCl + KOH
KCl + H2O
C. Al(OH)3 + HCl
AlCl3 + H2O
28) State whether each of the following is an acid, base or salt.
A. HCl B. NaOH C. NH4Cl D. HNO3 E. Ca(NO3)2
F. H2SO4 G. H2C2H3O2 H. KOH I. H3PO4 J. Al(OH)3
A. acid B. base C. salt D. acid E. salt
F. acid G. acid H. base I. acid J. base