CHEM 1332
SPRING 2005
Test 1 Version 1
1.
How much energy is needed to melt 180 grams of ice at 0 ºC? (The molar heat capacity of liquid water is 75.4 J/mol ºC. The molar
heat of vaporization of water is 40.7 kJ/mol. The molar heat of fusion of water is 6.02 kJ/mol.)
(A)
60.2 kJ
2.
Which of the following substances has the highest boiling point?
(A)
NaCl
3.
Which of the following intermolecular forces exist in all solid substances?
(A)
(D)
Dispersion forces
Ion-dipole forces
4.
Which of the following statements is true?
(A)
(B)
(C)
(D)
(E)
The triple point of a substance increases when the pressure increases.
The critical point of a substance decrease when the temperature increases.
Both the triple point and the critical point of a substance increase with a decrease in temperature.
Both the triple point and the critical point of a substance are dependent on the substance only, but not on temperature or pressure.
None of the above are true.
5.
Which of the following substances would be the most soluble in heptane (C7H16)?
(A)
(D)
calcium carbonate
water
(B)
(B)
1083.6 kJ
Kr
(C)
(C)
(B)
(E)
(B)
(E)
407 kJ
Methanol (CH3OH)
Dipole-dipole forces
Hydrogen bonding
methanol (CH3OH)
benzene (C6H6)
1
(D)
7326kJ
(E)
6.02 kJ
(D)
H2O
(E)
Ne
(C)
Ion-induced dipole forces
(C)
sodium chloride
6.
Which of the following statements is TRUE?
(A)
(B)
(C)
(D)
(E)
The entropy of a solution is ALWAYS greater than the entropy of the separate components.
In any solution, the solvent has to be liquid.
The solubility of a gas in a liquid is inversely proportional to the pressure.
If the heat of solution is negative for a solid in a liquid, then more solid will dissolve at lower temperatures.
All of these statements are false.
7.
Commercial concentrated nitric acid is 69.0 % by mass HNO3 and has a density of 1.42 g/mL. Calculate the molarity of
concentrated nitric acid.
(A)
0.156 M
8.
Calculate the number of moles of ions present in 356 mL of 0.358 M Ca(NO3)2.
(A)
(D)
0.0425 moles of ions
0.382 moles ions
9.
How much naphthalene (C10H8, MM = 128 g/mol) must be dissolved in 500. g of benzene (C6H6, MM = 78 g/mol) to produce a
solution that has a freezing point of 0.38 ºC. (You might want to know that the freezing point of benzene is 5.5 ºC and the value of Kf
is 5.12 ºC/m).
(A)
(D)
4.75 g naphthalene
128 g naphthalene
10.
Which of the following aqueous solutions would be expected to have the highest vapor pressure?
(A)
(D)
0.01 m NaCl
0.02 m CaCl2
(B)
7.71 M
(C)
(B)
(E)
(B)
(E)
(B)
(E)
11.0 M
0.127 moles ions
1.07 moles ions
9.52 g naphthalene
256 g naphthalene
0.05 m methanol (CH3OH)
0.03 m ethanol (C2H5OH)
2
(D)
15.6 M
(C)
0.255 moles ions
(C)
(C)
64 g naphthalene
0.01 m K2SO4
(E)
48.6 M
11.
(A)
3.21 g of an unknown non-electrolytic substance is dissolved in sufficient water to make 225 mL of solution. If the osmotic
pressure at 25.0 ºC is 35.1 torr, calculate the molar mass of the substance.
7.65 x 105g/mol
(B)
1007 g/mol
(C)
7550 g/mol
(D)
6.42 x 104 g/mol
(E)
12.
Consider the reaction, ATP Æ AMP + 2 P. If the rate of increase of [P] is 0.04M/s, at which rate is [ATP] decreasing?
(A)
0.08M/s
13.
The units of the rate constant for a third-order reaction are:
(A)
(D)
M/s
1/(M2.s)
14.
What is the rate law for the reaction: C2H4Br2 + 3KI → C2H4 + 2KBr +KI3, given the initial rate data below?
[C2H4Br2], M
0.500
0.500
1.50
(B)
0.01M/s
(B)
(E)
(C)
0.04M/s
1/(M.s)
None of these
(D)
0.02M/s
(C)
1/s
(E)
633 g/mol
0.06 M/s
∆[KI3]/∆t (M min-1)
0.269
1.08
0.807
[KI], M
1.80
7.20
1.80
(B)
(E)
rate = k[KI]
rate = k[KI][C2H4Br2]
15.
For the decomposition reaction 2N2O5(g) → 4NO2(g) + O2(g), the rate constant is 2.80 x 10-3 s-1 at 60 ºC. How long will it take for
75% of the initial N2O5 concentration to decompose?
(A)
0.021 s
16.
The rate constant for the reaction of HI molecules, HI(g) + HI(g) → H2(g) + I2(g), is 1.8 x 10-3 (M . s)-1 at 700 K. What is the
concentration of HI after 5.0 minutes if the initial concentration was 10.0 M?
(A)
5.8 M
(B)
(B)
5.60 x 10-3 s
9.9 M
rate = k[C2H4Br2]
rate = k[KI][ C2H4Br2]2
rate = k[KI]2
(A)
(D)
(C)
(C)
495 s
9.2 M
3
(C)
(D)
(D)
248 s
0.10 M
(E)
(E)
0.042 s
1.6 M
17.
For a given reaction, the value of the activation energy is 51.2 kJ/mol. Given that the rate constant at 25 ºC is 1.55 x 10-3 1/s, what
is the value of the rate constant at 45 ºC?
(A)
(D)
4.23 x 10-4 1/s
5.69 x 10-3 1/s
18.
What is the molecularity for each of the following elementary processes and what is the rate law for each?
(1)
(2)
(3)
N2O + Cl → N2 + ClO
Cl2 → 2Cl
NO + Cl2 → NOCl2
(A)
(B)
(C)
(D)
(E)
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl][Cl]; (3) bimolecular, rate = k [NO][Cl]2
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl2]; (3) termolecular, rate = k [NO][Cl]2
(1) tetramolecular, rate = k [N2][ClO]/([N2O][Cl]); (2) termolecular, rate = k [Cl]2/[Cl2];
(3) termolecular, rate = k [NOCl2]/([NO][Cl]2)
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl2]; (3) bimolecular, rate = k[NO][Cl2]
None of these
19.
Which of the following statements is FALSE?
(A)
(B)
(C)
(D)
(E)
In order for a reaction to occur, reactant molecules must collide.
A catalyst alters the rate of a reaction and is neither a product nor a reactant in the overall equation.
A catalyst does not affect the activation energy.
The rate of the bimolecular reaction A + B → products is proportional to the frequency of collisions between A and B.
The transition state is a short-lived, high energy state, intermediate between reactants and products.
(B)
(E)
1.55 x 10-3 1/s
2.63 x 1054 1/s
(C)
THERE IS ANOTHER PAGE!!!
4
1.77 x 10-3 1/s
20.
Which of the following mechanisms is consistent with the observed rate law, rate = k[NO2]2, for the reaction 2 NO2 → 2 NO(g) +
O2(g)?
Mechanism 1:
NO2 + NO2 → N2O4
N2O4 → N2 + 2 O2
N2 + O2 → 2 NO
slow
fast
fast
Mechanism 2
NO2 → N + O2
NO2 + N → N2O2
N2O2 → 2 NO
slow
fast
fast
Mechanism 3
NO2 → NO + O
O + NO2 → NO + O2
(A)
(B)
(C)
(D)
(E)
slow
fast
All 3 mechanisms
Mechanisms 1 and 2 only
Mechanisms 1 and 3 only
Mechanisms 2 and 3 only
Mechanism 1 only
5
CHEM 1332
SPRING 2005
Test 1 Version 2
1.
Which of the following statements is TRUE?
(A)
(B)
(C)
(D)
(E)
The entropy of a solution is ALWAYS greater than the entropy of the separate components.
In any solution, the solvent has to be liquid.
The solubility of a gas in a liquid is inversely proportional to the pressure.
If the heat of solution is negative for a solid in a liquid, then more solid will dissolve at lower temperatures.
All of these statements are false.
2.
Commercial concentrated nitric acid is 69.0 % by mass HNO3 and has a density of 1.42 g/mL. Calculate the molarity of
concentrated nitric acid.
(A)
0.156 M
3.
Calculate the number of moles of ions present in 356 mL of 0.358 M Ca(NO3)2.
(A)
(D)
0.0425 moles of ions
0.382 moles ions
4.
How much naphthalene (C10H8, MM = 128 g/mol) must be dissolved in 500. g of benzene (C6H6, MM = 78 g/mol) to produce a
solution that has a freezing point of 0.38 ºC. (You might want to know that the freezing point of benzene is 5.5 ºC and the value of Kf
is 5.12 ºC/m).
(A)
(D)
4.75 g naphthalene
128 g naphthalene
(B)
7.71 M
(C)
(B)
(E)
(B)
(E)
11.0 M
0.127 moles ions
1.07 moles ions
9.52 g naphthalene
256 g naphthalene
1
(D)
15.6 M
(C)
0.255 moles ions
(C)
64 g naphthalene
(E)
48.6 M
5.
Which of the following aqueous solutions would be expected to have the highest vapor pressure?
(A)
(D)
0.01 m NaCl
0.02 m CaCl2
6.
How much energy is needed to melt 180 grams of ice at 0 ºC? (The molar heat capacity of liquid water is 75.4 J/mol ºC. The molar
heat of vaporization of water is 40.7 kJ/mol. The molar heat of fusion of water is 6.02 kJ/mol.)
(A)
60.2 kJ
7.
Which of the following substances has the highest boiling point?
(A)
NaCl
8.
Which of the following intermolecular forces exist in all solid substances?
(A)
(D)
Dispersion forces
Ion-dipole forces
9.
Which of the following statements is true?
(A)
(B)
(C)
(D)
(E)
The triple point of a substance increases when the pressure increases.
The critical point of a substance decrease when the temperature increases.
Both the triple point and the critical point of a substance increase with a decrease in temperature.
Both the triple point and the critical point of a substance are dependent on the substance only, but not on temperature or pressure.
None of the above are true.
10.
Which of the following substances would be the most soluble in heptane (C7H16)?
(A)
(D)
calcium carbonate
water
(B)
(E)
(B)
(B)
1083.6 kJ
Kr
0.05 m methanol (CH3OH)
0.03 m ethanol (C2H5OH)
(C)
(C)
(B)
(E)
(B)
(E)
407 kJ
Methanol (CH3OH)
Dipole-dipole forces
Hydrogen bonding
methanol (CH3OH)
benzene (C6H6)
2
(C)
0.01 m K2SO4
(D)
7326kJ
(E)
6.02 kJ
(D)
H2O
(E)
Ne
(C)
Ion-induced dipole forces
(C)
sodium chloride
11.
The rate constant for the reaction of HI molecules, HI(g) + HI(g) → H2(g) + I2(g), is 1.8 x 10-3 (M . s)-1 at 700 K. What is the
concentration of HI after 5.0 minutes if the initial concentration was 10.0 M?
(A)
5.8 M
12.
For a given reaction, the value of the activation energy is 51.2 kJ/mol. Given that the rate constant at 25 ºC is 1.55 x 10-3 1/s, what
is the value of the rate constant at 45 ºC?
(A)
(D)
4.23 x 10-4 1/s
5.69 x 10-3 1/s
13.
What is the molecularity for each of the following elementary processes and what is the rate law for each?
(1)
(2)
(3)
N2O + Cl → N2 + ClO
Cl2 → 2Cl
NO + Cl2 → NOCl2
(A)
(B)
(C)
(D)
(E)
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl][Cl]; (3) bimolecular, rate = k [NO][Cl]2
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl2]; (3) termolecular, rate = k [NO][Cl]2
(1) tetramolecular, rate = k [N2][ClO]/([N2O][Cl]); (2) termolecular, rate = k [Cl]2/[Cl2];
(3) termolecular, rate = k [NOCl2]/([NO][Cl]2)
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl2]; (3) bimolecular, rate = k [NO][Cl2]
None of these
14.
Which of the following statements is FALSE?
(A)
(B)
(C)
(D)
(E)
In order for a reaction to occur, reactant molecules must collide.
A catalyst alters the rate of a reaction and is neither a product nor a reactant in the overall equation.
A catalyst does not affect the activation energy.
The rate of the bimolecular reaction A + B → products is proportional to the frequency of collisions between A and B.
The transition state is a short-lived, high energy state, intermediate between reactants and products.
(B)
9.9 M
(C)
(B)
(E)
9.2 M
1.55 x 10-3 1/s
2.63 x 1054 1/s
(D)
(C)
3
0.10 M
(E)
1.77 x 10-3 1/s
1.6 M
15.
Which of the following mechanisms is consistent with the observed rate law, rate = k[NO2]2, for the reaction 2 NO2 → 2 NO(g) +
O2(g)?
Mechanism 1:
NO2 + NO2 → N2O4
N2O4 → N2 + 2 O2
N2 + O2 → 2 NO
slow
fast
fast
Mechanism 2
NO2 → N + O2
NO2 + N → N2O2
N2O2 → 2 NO
slow
fast
fast
Mechanism 3
NO2 → NO + O
O + NO2 → NO + O2
slow
fast
(A)
(B)
(C)
(D)
(E)
All 3 mechanisms
Mechanisms 1 and 2 only
Mechanisms 1 and 3 only
Mechanisms 2 and 3 only
Mechanism 1 only
16.
3.21 g of an unknown non-electrolytic substance is dissolved in sufficient water to make 225 mL of solution. If the osmotic
pressure at 25.0 ºC is 35.1 torr, calculate the molar mass of the substance.
(A)
7.65 x 105g/mol
(B)
1007 g/mol
(C)
7550 g/mol
4
(D)
6.42 x 104 g/mol
(E)
633 g/mol
17.
Consider the reaction, ATP Æ AMP + 2 P. If the rate of increase of [P] is 0.04M/s, at which rate is [ATP] decreasing?
(A)
0.08M/s
18.
The units of the rate constant for a third-order reaction are:
(A)
(D)
M/s
1/(M2.s)
19.
What is the rate law for the reaction: C2H4Br2 + 3KI → C2H4 + 2KBr +KI3, given the initial rate data below?
[C2H4Br2], M
0.500
0.500
1.5
(B)
0.01M/s
(B)
(E)
(C)
0.04M/s
1/(M.s)
None of these
(D)
0.02M/s
(C)
1/s
(E)
0.06 M/s
∆[KI3]/∆t (M min-1)
0.269
1.08
0.807
[KI], M
1.80
7.20
1.80
(B)
(E)
rate = k[KI]
rate = k[KI][C2H4Br2]
20.
For the decomposition reaction 2N2O5(g) → 4NO2(g) + O2(g), the rate constant is 2.80 x 10-3 s-1 at 60 ºC. How long will it take for
75% of the initial N2O5 concentration to decompose?
(A)
0.021 s
(B)
5.60 x 10-3 s
rate = k[C2H4Br2]
rate = k[KI][ C2H4Br2]2
rate = k[KI]2
(A)
(D)
(C)
495 s
5
(C)
(D)
248 s
(E)
0.042 s
CHEM 1332
SPRING 2005
Test 1 Version 3
1.
(A)
3.21 g of an unknown non-electrolytic substance is dissolved in sufficient water to make 225 mL of solution. If the osmotic
pressure at 25.0 ºC is 35.1 torr, calculate the molar mass of the substance.
7.65 x 105g/mol
(B)
1007 g/mol
(C)
7550 g/mol
(D)
6.42 x 104 g/mol
(E)
2.
Consider the reaction, ATP Æ AMP + 2 P. If the rate of increase of [P] is 0.04M/s, at which rate is [ATP] decreasing?
(A)
0.08M/s
3.
The units of the rate constant for a third-order reaction are:
(A)
(D)
M/s
1/(M2.s)
4.
What is the rate law for the reaction: C2H4Br2 + 3KI → C2H4 + 2KBr +KI3, given the initial rate data below?
[C2H4Br2], M
0.500
0.500
1.50
(B)
0.01M/s
(B)
(E)
(C)
0.04M/s
1/(M.s)
None of these
(D)
0.02M/s
(C)
1/s
(E)
633 g/mol
0.06 M/s
∆[KI3]/∆t (M min-1)
0.269
1.08
0.807
[KI], M
1.80
7.20
1.80
(B)
(E)
rate = k[KI]
rate = k[KI][C2H4Br2]
5.
For the decomposition reaction 2N2O5(g) → 4NO2(g) + O2(g), the rate constant is 2.80 x 10-3 s-1 at 60 ºC. How long will it take for
75% of the initial N2O5 concentration to decompose?
(A)
0.021 s
(B)
5.60 x 10-3 s
rate = k[C2H4Br2]
rate = k[KI][ C2H4Br2]2
rate = k[KI]2
(A)
(D)
(C)
495 s
1
(C)
(D)
248 s
(E)
0.042 s
6.
The rate constant for the reaction of HI molecules, HI(g) + HI(g) → H2(g) + I2(g), is 1.8 x 10-3 (M . s)-1 at 700 K. What is the
concentration of HI after 5.0 minutes if the initial concentration was 10.0 M?
(A)
5.8 M
7.
For a given reaction, the value of the activation energy is 51.2 kJ/mol. Given that the rate constant at 25 ºC is 1.55 x 10-3 1/s, what
is the value of the rate constant at 45 ºC?
(A)
(D)
4.23 x 10-4 1/s
5.69 x 10-3 1/s
8.
What is the molecularity for each of the following elementary processes and what is the rate law for each?
(1)
(2)
(3)
N2O + Cl → N2 + ClO
Cl2 → 2Cl
NO + Cl2 → NOCl2
(A)
(B)
(C)
(D)
(E)
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl][Cl]; (3) bimolecular, rate = k [NO][Cl]2
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl2]; (3) termolecular, rate = k [NO][Cl]2
(1) tetramolecular, rate = k [N2][ClO]/([N2O][Cl]); (2) termolecular, rate = k [Cl]2/[Cl2];
(3) termolecular, rate = k [NOCl2]/([NO][Cl]2)
(1) bimolecular, rate = k[N2O][Cl]; (2) unimolecular, rate = k [Cl2]; (3) bimolecular, rate = k [NO][Cl2]
None of these
9.
Which of the following statements is FALSE?
(A)
(B)
(C)
(D)
(E)
In order for a reaction to occur, reactant molecules must collide.
A catalyst alters the rate of a reaction and is neither a product nor a reactant in the overall equation.
A catalyst does not affect the activation energy.
The rate of the bimolecular reaction A + B → products is proportional to the frequency of collisions between A and B.
The transition state is a short-lived, high energy state, intermediate between reactants and products.
(B)
9.9 M
(C)
(B)
(E)
9.2 M
1.55 x 10-3 1/s
2.63 x 1054 1/s
(D)
(C)
2
0.10 M
(E)
1.77 x 10-3 1/s
1.6 M
10.
Which of the following mechanisms is consistent with the observed rate law, rate = k[NO2]2, for the reaction 2 NO2 → 2 NO(g) +
O2(g)?
Mechanism 1:
NO2 + NO2 → N2O4
N2O4 → N2 + 2 O2
N2 + O2 → 2 NO
slow
fast
fast
Mechanism 2
NO2 → N + O2
NO2 + N → N2O2
N2O2 → 2 NO
slow
fast
fast
Mechanism 3
NO2 → NO + O
O + NO2 → NO + O2
slow
fast
(A)
(B)
(C)
(D)
(E)
All 3 mechanisms
Mechanisms 1 and 2 only
Mechanisms 1 and 3 only
Mechanisms 2 and 3 only
Mechanism 1 only
11.
How much energy is needed to melt 180 grams of ice at 0 ºC? (The molar heat capacity of liquid water is 75.4 J/mol ºC. The molar
heat of vaporization of water is 40.7 kJ/mol. The molar heat of fusion of water is 6.02 kJ/mol.)
(A)
60.2 kJ
(B)
1083.6 kJ
(C)
407 kJ
3
(D)
7326kJ
(E)
6.02 kJ
12.
Which of the following substances has the highest boiling point?
(A)
NaCl
13.
Which of the following intermolecular forces exist in all solid substances?
(A)
(D)
Dispersion forces
Ion-dipole forces
14.
Which of the following statements is true?
(A)
(B)
(C)
(D)
(E)
The triple point of a substance increases when the pressure increases.
The critical point of a substance decrease when the temperature increases.
Both the triple point and the critical point of a substance increase with a decrease in temperature.
Both the triple point and the critical point of a substance are dependent on the substance only, but not on temperature or pressure.
None of the above are true.
15.
Which of the following substances would be the most soluble in heptane (C7H16)?
(A)
(D)
calcium carbonate
water
16.
Which of the following statements is TRUE?
(A)
(B)
(C)
(D)
(E)
The entropy of a solution is ALWAYS greater than the entropy of the separate components.
In any solution, the solvent has to be liquid.
The solubility of a gas in a liquid is inversely proportional to the pressure.
If the heat of solution is negative for a solid in a liquid, then more solid will dissolve at lower temperatures.
All of these statements are false.
(B)
Kr
(C)
(B)
(E)
(B)
(E)
Methanol (CH3OH)
Dipole-dipole forces
Hydrogen bonding
methanol (CH3OH)
benzene (C6H6)
4
(D)
H2O
(C)
Ion-induced dipole forces
(C)
sodium chloride
(E)
Ne
17.
Commercial concentrated nitric acid is 69.0 % by mass HNO3 and has a density of 1.42 g/mL. Calculate the molarity of
concentrated nitric acid.
(A)
0.156 M
18.
Calculate the number of moles of ions present in 356 mL of 0.358 M Ca(NO3)2.
(A)
(D)
0.0425 moles of ions
0.382 moles ions
19.
How much naphthalene (C10H8, MM = 128 g/mol) must be dissolved in 500. g of benzene (C6H6, MM = 78 g/mol) to produce a
solution that has a freezing point of 0.38 ºC. (You might want to know that the freezing point of benzene is 5.5 ºC and the value of Kf
is 5.12 ºC/m).
(A)
(D)
4.75 g naphthalene
128 g naphthalene
20.
Which of the following aqueous solutions would be expected to have the highest vapor pressure?
(A)
(D)
0.01 m NaCl
0.02 m CaCl2
(B)
7.71 M
(C)
(B)
(E)
(B)
(E)
(B)
(E)
11.0 M
0.127 moles ions
1.07 moles ions
9.52 g naphthalene
256 g naphthalene
0.05 m methanol (CH3OH)
0.03 m ethanol (C2H5OH)
5
(D)
15.6 M
(C)
0.255 moles ions
(C)
(C)
64 g naphthalene
0.01 m K2SO4
(E)
48.6 M