Q: For the reaction $$2HI(g) \rightarrow H_2$(g) + I_2$(g)$$, which is the correct rate expression with respect to HI?

$$\text{Rate} = -\dfrac{1}{2} \dfrac{d[HI]}{dt}$$

Q: For the reaction $$2NO(g) + Br_2$(g) \rightarrow 2NOBr(g)$$, initial rate data are given below: | [NO] (M) | [Br$$_2$$] (M) | Rate (M/s) | |---|---|---| | 0.10 | 0.20 | 24 | | 0.25 | 0.20 | 150 | | 0.10 | 0.50 | 60 | | 0.35 | 0.50 | 735 | What is the rate law for this reaction?

$$\text{Rate} = k[NO]^2[Br_2$]$$

Q: In the reaction $$2NO(g) + Br_2$(g) \rightarrow 2NOBr(g)$$, how is the rate of appearance of NOBr related to the rate of disappearance of Br$$_2$$?

$$\text{Rate of appearance of NOBr} = 2 \times \text{Rate of disappearance of Br}_2$$

Q: A solution contains both water and ethanol as volatile components. Which equation should be used to calculate the total vapor pressure above the solution?

$$P_{\text{total}} = X$$_{\text{H}$$_2\text{O}} P^0$_{\text{H}_2\text{O}} + X_{\text{EtOH}} P^0$_{\text{EtOH}}$$

Question 1

Which of the following aqueous solutions will exhibit the most ion-pairing?

Accepted Answer

0.03 m MgSO$$_4$$

Question 2

Considering ion-pairing, which aqueous solution has the lowest freezing point?

Accepted Answer

0.06 m sugar

Question 3

A solution is prepared by dissolving 2.05 g of KBr (MW = 119 g/mol) and 4.82 g of glucose (MW = 180 g/mol) in 186 g of H$$_2O. If $$the freezing point depression constant $$K_f$$ for water is 1.86 $$^	ext{o}C/m$$, what is the freezing point of the solution?

Accepted Answer

$$-0.61^	ext{o}C$$

Question 4

Given the solution in the previous question, the vapor pressure of pure water at 20$$^	ext{o}C is 17.4 $$torr. What is the vapor pressure of water in the solution?

Accepted Answer

17.3 torr

Question 5

Which equation correctly expresses the osmotic pressure ($$\pi) of a $$solution?

Accepted Answer

$$\pi = \dfrac{n}{V}RT = MRT$$

Question 6

A 2.610 g sample of a nonelectrolyte organic compound is dissolved in enough water to make 250 mL of solution. The osmotic pressure is measured to be 0.566 atm at 25$$^	ext{o}C. $$What is the molar mass of the compound?

Accepted Answer

451 g/mol

Question 7

Which factor does NOT affect the rate of a chemical reaction?

Accepted Answer

Color of reactants

Question 8

For the reaction $$2HI(g) \rightarrow H_2$(g) + I_2$(g)$$, which is the correct rate expression with respect to HI?

Accepted Answer

$$	ext{Rate} = -\dfrac{1}{2} \dfrac{d[HI]}{dt}$$

Question 9

For the general reaction $$aA + bB \rightarrow cC + dD$$, which of the following correctly relates the rates of change of the reactants and products?

Accepted Answer

$$-\dfrac{1}{a} \dfrac{d[A]}{dt} = -\dfrac{1}{b} \dfrac{d[B]}{dt} = \dfrac{1}{c} \dfrac{d[C]}{dt} = \dfrac{1}{d} \dfrac{d[D]}{dt}$$

Question 10

If tripling the concentration of reactant A multiplies the rate by a factor of nine, what is the reaction order in A?

Accepted Answer

Second

Question 11

For the reaction $$2NO(g) + Br_2$(g) \rightarrow 2NOBr(g)$$, initial rate data are given below:

| [NO] (M) | [Br$$_2$$] (M) | Rate (M/s) |
|---|---|---|
| 0.10 | 0.20 | 24 |
| 0.25 | 0.20 | 150 |
| 0.10 | 0.50 | 60 |
| 0.35 | 0.50 | 735 |

What is the rate law for this reaction?

Accepted Answer

$$	ext{Rate} = k[NO]^2[Br_2$]$$

Question 12

For the reaction $$2NO(g) + Br_2$(g) ightarrow 2NOBr(g)$$, what is the rate of disappearance of Br$$_2$$ when [NO] = 0.075 M and [Br$$_2$$] = 0.25 M, given the rate law $$	ext{Rate} = k[NO]^2[Br_2$]$$ and $$k = 6000 M$^{-2}s$^{-1}$$?

Accepted Answer

25.3 M/s

Question 13

Which of the following statements about catalysts is TRUE?

Accepted Answer

Catalysts speed up reactions by changing the reaction mechanism and are not consumed during the reaction.

Question 14

For the reaction $$W + X ightarrow Y + 2Z$$, if the rate law is $$	ext{Rate} = k[W][X]$$, what is the order of the reaction with respect to X?

Accepted Answer

First

Question 15

In the reaction $$2NO(g) + Br_2$(g) \rightarrow 2NOBr(g)$$, how is the rate of appearance of NOBr related to the rate of disappearance of Br$$_2$$?

Accepted Answer

$$	ext{Rate of appearance of NOBr} = 2 	imes 	ext{Rate of disappearance of Br}_2$$

Question 16

Which of the following best describes the effect of increasing temperature on reaction rate?

Accepted Answer

It increases the kinetic energy of molecules, leading to more frequent and energetic collisions.

Question 17

A solution contains both water and ethanol as volatile components. Which equation should be used to calculate the total vapor pressure above the solution?

Accepted Answer

$$P_{	ext{total}} = X$$_{	ext{H}$$_2	ext{O}} P^0$_{	ext{H}_2	ext{O}} + X_{	ext{EtOH}} P^0$_{	ext{EtOH}}$$

Colligative Properties and Chemical Kinetics: Study Notes

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