Practice for Final

Final Review – Chemistry 102
You should know the Arrhenius, van’t Hoff, Henderson-Hasselbalch, and Nernst equations.
1) The vapor pressure of a given liquid will increase if
a) The temperature is increased.
b) The volume is decreased.
c) The pressure is increased.
d) The temperature is decreased.
2) Non-polar compounds like oil will not dissolve in water. Why?
a) The interactions between the oil molecules
b) Polar solvents like water are more likely to
are very weak.
dissolve ionic substances.
c) The interactions between the solvent
d) Water is a non-polar solvent.
molecules are very weak.
3) The solubility of NaCl at 20ºC is 36g/100 mL of water. If 75 g of NaCl were poured into 200 grams
of water, and the mixture stirred for 20 minutes, what kind of solution would have formed?
a) Saturated solution
b) Supersaturated solution
c) Unsaturated solution
d) Pure solvent
4) All of the following factors affect the initial rate of a reaction EXCEPT
a) The concentration of the reactants
b) The nature of the reactants
c) The concentration of the products
d) The temperature
5) A reaction is discovered to have the following rate law.
Rate = k[NO2]2
If the concentration of NO2 is tripled, the rate of the reaction will
a) Double
b) Increase by a factor of nine.
c) Quadruple
d) Increase by a factor of three.
6) After three half lives have elapsed for a first-order decay process
a) 12.5% of the reactant decayed to product
b) 87.5% of the reactant decayed to product
c) 75% of the reactant decayed to product
d) 50% of the reactant decayed to product
7) The detailed sequence of elementary processes (reaction steps) that leads to the net overall
reaction is called the
a) mechanism
b) stoichiometry
c) rate law
d) potential
8) As time goes by during a chemical reaction, the rate of the reaction often decreases because
a) as products form, the reverse reaction may
b) as the reaction proceeds, the concentrations
become a factor in the overall rate
of reactants decreases
c) as the reaction proceeds, the rate constant
d) none of the above are correct
will decrease
9) A catalyst works by
a) decreasing the temperature of the reaction
c) increasing the enthalpy change (ΔH) of the
b) decreasing the differences in the energies of
the products vs. the reactants
d) decreasing the activation energy of the rate
limiting step
Version: 2010 Spring
Final Review – Chemistry 102
10) The equilibrium constant for the reaction below is KC = 55 at 425⁰C. If initial concentrations are
[H2] = [I2] = 3.00 M and [HI] = 2.00 M, which direction will the reaction shift?
H2(g) + I2(g) = 2 HI(g)
a) Will not shift, it is at equilibrium
b) Will not shift, it is a gas phase reaction
c) Towards reactants
d) Towards products
11) The equilibrium constant for the reaction below is KC = 55 at 425⁰C. The value for the equilibrium
constant will be changed if
H2(g) + I2(g) = 2 HI(g)
b) Concentrations are given in Torr instead of M
a) Temperature is changed to 400⁰C
c) A catalyst is added to the reaction system
d) Additional HI is added to the reaction system
12) From an equilibrium constant for a reaction, one can predict all of the following EXCEPT
a) the extent of reaction towards products
b) the effect of a change in temperature
c) the direction of the reaction
d) the effect of a change in concentrations
13) Which is the best definition of a Lewis base?
a) A proton acceptor
c) A substance that accepts hydroxide ions
14) For a given weak acid, HA, the value of Ka
a) will not change with temperature
c) = [H3O+][A–] / [H2O][HA]
15) A solution has a pH of 11. What is the pOH?
a) 14
c) 3
b) An electron pair acceptor
d) An electron pair donor
b) will be a number less than 1 and often much
less than 1
d) cannot be greater than 10 –7
b) 11
d) 7
16) What is the hydrogen ion concentration of a solution of pH = 8.6?
a) 2.5×10 – 9
b) 8.6×10 0
c) 3.9×10 – 8
d) 5.4
17) A solution with pH = 8.12 would be described as
a) slightly basic
b) slightly acidic
c) very basic
d) very acidic
18) A solution of the salt of a weak acid, HA, generally has a pH > 7 because
a) no HA is formed
b) A– reacts with water to produce HA and OH–
c) [H ] is less than 10
d) the salt of a weak acid makes a strong acid
19) Consider the Ka values for the following acids
H2S (8.9×10–8)
HOBr (2.5×10–9)
Which of the following is the weakest base?
a) OBr –
b) F–
c) HS
d) NO2–
20) Which of the following will be a buffer when dissolved in 1.0 L of water?
a) 1.0 mol NaH2PO4 and 0.01 mol Na2HPO4
b) 0.3 mol HF and 0.3 mol NaF
c) 0.5 mol Na+ and 0.5 mol Cl–
d) 0.2 mol HCl and 0.2 mol NaOH
Version: 2010 Spring
Final Review – Chemistry 102
21) Which of the following, when added to water, will decrease the pH of the solution?
a) NaHCO3
b) KCN
c) NH4Cl
d) None of the above will change the pH
22) Calculate the pH of a 1.20 M nitrous acid solution. (Ka = 4.50×10–4)
a) 3.35
b) 4.50
c) 1.20
d) 1.63
23) The expression for the KSP of the insoluble substance, Bi2S3 is
a) [Bi3+][S2–]
b) [2Bi3+][3S2–]
c) [Bi3+]3[S2–]2
d) [Bi3+]2[S2–]3
24) What would be the best way to increase the solubility of Mg(OH)2(s)?
a) add a strong acid
b) add a weak acid
c) add a strong base
d) add a weak base
25) An amphoteric substance
a) reacts with both acids and bases
c) has two charges at the same time
b) is insoluble in water
d) has both male and female forms
26) The anode in a voltaic cell and in an electrolytic cell
a) is positive
b) is the site of reduction
c) is negative
d) is the site of oxidation
27) An electrochemical cell would have a potential of zero volts when
a) the concentrations reach 1.0 M
b) the standard potential becomes positive
c) the system is at equilibrium
d) the cathode has mostly corroded away
28) In the Nernst equation, Ecell = Eº + (RT/nF)lnQ, the term F represents the
a) number of electrons transferred
b) number of coulombs per mole of electrons
c) measured voltage
d) equilibrium constant for the reaction
True / False
29) Dissolving a solid solute in a liquid will increase the vapor pressure and increase the boiling point.
30) As the concentration of weak acids decrease, the percent dissociation increases.
31) All strong acids and strong bases are strong electrolytes.
32) Spontaneous reactions always have a positive value of ΔG.
33) Spontaneous reactions always have a negative value of Eº.
34) The pH of a solution of the strong base, NaOH, would be expected to be less than seven (7).
35) Oxidation involves the loss of electrons.
Version: 2010 Spring
Final Review – Chemistry 102
1) a
2) b
3) a
4) c
5) b
6) b
7) a
8) b
9) d
10) d
11) a
12) b
13) d
14) b
15) c
16) a
17) a
18) b
19) b
20) b
21) c
22) d
23) d
24) a
25) a
26) d
27) c
28) b
29) F
30) T
31) T
32) F
33) F
34) F
35) T
Version: 2010 Spring