1) When a particular solid begins to dissolve in water, the temperature rises dramatically. For the dissolving of this solid in pure water

A) Î"Hsoln is always negative and Î"Ssoln may be negative or positive.

B) Î"Hsoln is always negative and Î"Ssoln is always positive.

C) Î"Hsoln is always positive and Î"Ssoln may be negative or positive.

D) Î"Hsoln is always positive and Î"Ssoln is always positive.

2) What is the mole fraction of I2 in a solution made by dissolving 27.8 g of I2 in 245 g of hexane, C6H14?

A) 0.0371

B) 0.0385

C) 0.0715

D) 0.0770

3) A solution is prepared by dissolving 17.75 g sulfuric acid, H2SO4, in enough water to make 100.0 mL of solution. If the density of the solution is 1.1094 g/mL, what is the mole fraction H2SO4 in the solution?

A) 0.0181

B) 0.0338

C) 0.0350

D) 19.0

4) A solution is prepared by dissolving 17.75 g sulfuric acid, H2SO4, in enough water to make 100.0 mL of solution. If the density of the solution is 1.1094 g/mL, what is the molarity?

A) 0.1775 M H2SO4

B) 0.1810 M H2SO4

C) 1.810 M H2SO4

D) 1.940 M H2SO4

5) A solution is prepared by dissolving 171 g of CdCl2 in enough water to make exactly 250.0 mL of solution. If the density of the solution is 1.556 g/mL, what is the weight percent of CdCl2 in the solution?

A) 7.17%

B) 44.0%

C) 56.0%

D) 68.4%

6) What molality of pentane is obtained by dissolving 5.0 g pentane, C5H12, in 245.0 g hexane, C6H14?

A) 0.020 m

B) 0.024 m

C) 0.28 m

D) 20. m

7) The Henry's Law constant of methyl bromide, CH3Br, is k = 0.159 mol/(L âˆ^TM atm) at 25 °C. What is the solubility of methyl bromide in water at 25 °C and at a partial pressure of 125. mm Hg?

A) 0.0523 mol/L

B) 0.0329 mol/L

C) 0.0483 mol/L

D) 0.0261 mol/L

8) A NaCl solution is prepared by dissolving 18.3 g NaCl in 500.0 g of water at 70 °C. What is the vapor pressure of the solution if the vapor pressure of pure water at 70 °C is 233.7 mm Hg? Assume a vanâ€^TMt Hoff factor of 1.9

A) 228.8 mm Hg

B) 206.1 mm Hg

C) 272.9 mm Hg

D) 255.5 mm Hg

9) The normal boiling point of pure benzene is found to be 80.10 °C. What is the approximate molecular weight of a nonionizing substance if a solution of 3.55 g of the substance dissolved in 100. g of benzene has a normal boiling point of 80.19 °C? Kb = 5.12 °C/m for benzene, C6H6.

A) 20 amu

B) 500 amu

C) 2000 amu

D) 20,000 amu

10) A solution is made by dissolving 13 g of sucrose, C12H22O11, in 117 g of water, producing a solution with a volume of 125 mL at 20 °C. What is the expected osmotic pressure at 20 °C?

A) 7.3 atm

B) 10 atm

C) 14 atm

D) 58 atm

11) The decomposition of dinitrogen pentoxide is described by the chemical equation

2 N2O5(g) â†' 4 NO2(g) + O2(g)

If the rate of disappearance of N2O5 is equal to 1.40 mol/min at a particular moment, what is the rate of appearance of NO2 at that moment?

A) 0.700 mol/min

B) 1.40 mol/min

C) 2.80 mol/min

D) 5.60 mol/min

12) Hydrogen peroxide decomposes to water and oxygen according to the reaction below:

2 H2O2(aq) â†' 2 H2O(l) + O2(g)

In the presence of large excesses of I- ion, the following set of data is obtained. What is the average rate of disappearance of H2O2(aq) in M/s in the first 45.0 seconds of the reaction if 1.00 L of H2O2 reacts at 25 °C and 1.00 atm pressure?

A) 9.09 Ã- 10-7 M/s

B) 3.63 Ã- 10-6 M/s

C) 4.33 Ã- 10-5 M/s

D) 1.64 Ã- 10-4 M/s

13) The following set of data was obtained by the method of initial rates for the reaction:

2 HgCl2(aq) + C2O42-(aq) â†' 2 Cl-(aq) + 2 CO2(g) + Hg2Cl2(s)

What is the value of the rate constant, k?

A) 1.4 Ã- 10-8 1/M2âˆ^TMs

B) 1.3 Ã- 10-7 1/M2âˆ^TMs

C) 1.4 Ã- 10-5 1/M2âˆ^TMs

D) 1.3 Ã- 10-4 1/M2âˆ^TMs

14) The following set of data was obtained by the method of initial rates for the reaction:

(H3C)3CBr + OH- â†' (H3C)3COH + Br-

What is the order of reaction with respect to ion, OH-?

A) zero

B) first

C) second

D) none of these

15) The first-order reaction, SO2Cl2 â†' SO2 + Cl2, has a rate constant equal to 2.20 Ã- 10-5 s-1 at 593 K. What percentage of the initial amount of SO2Cl2 will remain after 2.00 hours?

A) 1.00%

B) 14.7%

C) 17.1%

D) 85.4%

16) Acetaldehyde decomposes at 750 K: CH3CHO â†' CO + CH4. The reaction is first order in acetaldehyde and the half-life of the reaction is found to be 530 seconds. What is the rate constant for the reaction at this temperature?

A) 2.7 x 10-3 s-1

B) 1.3 x 10-3 s-1

C) 2.7 x 102 s-1

D) 7.6 x 102 s-1