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WorksheetsSoln, Thermo, & Rxn Rate Exam
Total questions: 30
Worksheet time: 30mins
Which of the following usually makes a substance dissolve faster in a solvent?
a. agitating the solution
b. increasing the particle size of the solute
c. lowering the temperature
d. decreasing the number of particles
a
b
c
d
What is the maximum amount of KCl that can dissolve in 200 g of water?
(The solubility of KCl is 34 g/100 g H2O at 20C.)
a. 17 g b. 34 g c. 68 g d. 6800 g
a
b
c
d
If the solubility of a gas in water is 4.0 g/L when the pressure of the gas above the water is 3.0 atm, what is the pressure of the gas above the water when the solubility of the gas is 1.0 g/L?
a. 0.75 atm b. 1.3 atm c. 4.0 atm d. 12 atm
a
b
c
d
What is the molarity of 200 mL of solution in which 2.0 moles of sodium bromide is dissolved?
a. 2.0M b. 10M c. 0.40M d. 4.0M
a
b
c
d
How many mL of a 2.0M NaBr solution are needed to make 200.0 mL of 0.50M NaBr?
a. 25 mL b. 50 mL c. 100 mL d. 150 mL
a
b
c
d
If 2.0 mL of 6.0M HCl is used to make a 500.0-mL aqueous solution, what is the molarity of the dilute solution?
a. 0.024M b. 0.24M c. 0.30M d. 0.83M
a
b
c
d
If the percent (mass/mass) for a solute is 4% and the mass of the solution is 200 g, what is the mass of solute in solution?
a. 8.0 g b. 50 g c. 80 g d. 800 g
a
b
c
d
How many milliliters of alcohol are in 167 mL of an 85.0% (v/v) alcohol solution?
a. 252 mL b. 228 mL c. 145 mL d. 142 mL
a
b
c
d
What is the mole fraction of ethanol in a solution of 3.00 moles of ethanol and 5.00 moles of water?
a. 0.375 b. 0.6 c. 1.67 d. 15
a
b
c
d
What is the molality of a solution containing 8.0 grams of solute in 0.50 kg of solvent? (molar mass of solute = 24 g)
a. 0.67m b. 4m c. 1.67m d. 0.17m
a
b
c
d
What is the freezing point of a solution of 0.5 mol of LiBr in 500 mL of water? (Kf = 1.86C/m)
a. –1.86C b. –3.72C c. –5.58C d. –7.44C
a
b
c
d
What is the boiling point of a solution that contains 3 moles of KBr in 2000 g of water? (Kb = 0.512C/m; molar mass of water = 18 g)
a. 97C b. 99.7C c. 101.5C d. 103C
a
b
c
d
What would likely happen if you were to touch the flask in which an endothermic reaction were occurring?
a. The flask would probably feel cooler than before the reaction started.
b. The flask would probably feel warmer than before the reaction started.
c. The flask would feel the same as before the reaction started.
d. none of the above
a
b
c
d
What is the specific heat of a substance if 1560 cal are required to raise the temperature of a 312-g sample by 15°C?
a. 0.033 cal/g°C
b. 0.33 cal/g°C
c. 0.99 cal/g°C
d. 1.33 cal/g°C
a
b
c
d
When 45 g of an alloy, at 25°C, are dropped into 100.0 g of water, the alloy absorbs 956 cal of heat. If the final temperature of the alloy is 37°C, what is its specific heat?
a. 0.423 cal/g°C
b. 1.77 cal/g°C
c. 9.88 cal/g°C
d. 48.8 cal/g°C
a
b
c
d
Calculate ΔH for the following reaction.
C2H4(g) + H2(g) C2H6(g)
(ΔHοf for C2H4(g) = 52.5 kJ/mol; ΔHοf for C2H6(g) = –84.7 kJ/mol)
a. –137.2 kJ b. –32.2 kJ c. 32.2 kJ d. 137.2 kJ
a
b
c
d
Why does a higher temperature cause a reaction to go faster?
a. There are more collisions per second only.
b. Collisions occur with greater energy only.
c. There are more collisions per second and the collisions are of greater energy.
d. There are more collisions per second or the collisions are of greater energy.
a
b
c
d
Why does a catalyst cause a reaction to proceed faster?
a. There are more collisions per second only.
b. The collisions occur with greater energy only.
c. The activation energy is lowered only.
d. There are more collisions per second and the collisions are of greater energy.
a
b
c
d
Consider the reaction N2g) 3H2(g)↔2NH3(g). What is the effect of decreasing the volume on the contained gases?
a. The reaction shifts toward the product gas.
b. The system reacts by increasing the number of gas molecules.
c. The pressure on the gases decreases momentarily.
d. Ammonia is consumed in the reaction.
a
b
c
d
Which of the changes listed below would shift the following reaction to the right?
4HCl(g) + O2 (g) ↔2Cl2 (g) + 2H2O(g)
a. addition of Cl2
b. removal of O2
c. increase of pressure
d. decrease of pressure
a
b
c
d
What is the effect of adding more water to the following equilibrium reaction?
CO2+ H2O ↔ H2CO3
a. More H2CO3 is produced.
b. CO2 concentration increases.
c. The equilibrium is pushed in the direction of reactants.
d. There is no effect.
a
b
c
d
What is the equilibrium constant for the following reaction?
C + O2 ↔ CO2
[C][O2]/[CO2]
[CO2]/[C][O2]
[C]2[O2]2/[CO2]2
[CO2]2/[C]2[O2]2
The Keq of a reaction is 4 x10-7. At equilibrium, the ____.
a. reactants are favored
b. products are favored
c. reactants and products are present in equal amounts
d. rate of the forward reaction is much greater than the rate of the reverse reaction
a
b
c
d
Which one of the following systems has the highest entropy?
a. 10 mL of water at 10°C
b. 10 mL of water at 50°C
c. 10 mL of water at 100°C
d. All have the same entropy because all are water.
a
b
c
d
Which reaction results in the greatest increase in entropy?
a. A → B
b. A → 2B
c. 2A → B
d. 3A → B
a
b
c
d
In which of these systems is the entropy decreasing?
a. air escaping from a tire
b. snow melting
c. salt dissolving in water
d. a liquid cooling
a
b
c
d
Which of the following is true about the numerical value of Gibbs free-energy change for a spontaneous reaction?
a. It is not related to enthalpy.
b. It is negative.
c. It indicates that work must be expended.
d. It is positive for temperatures above 850°C.
a
b
c
d
What is the rate law for the following reaction?
A + 2B → C + D
a. rate = k[A][B]
b. rate = k[A]2[B]
c. rate = k[A][B]2
d. rate = k[A]2[B]2
a
b
c
d
What is the order of the following reaction? A + 2B → C + D
a. zero b. first c. second d. third
a
b
c
d
In a first-order reaction, how does the rate change if the concentration of the reactant decreases to one-third its original value?
a. The rate decreases by a factor of one-ninth.
b. The rate decreases by a factor of one-third.
c. The rate decreases by a factor of one-half.
d. The rate stays the same
a
b
c
d
