Q: Consider the reaction $$A + 3B \rightarrow 2C. $$Which of the following correctly expresses the rate in terms of the change in concentration of $$C$$?

$$\text{rate} = \frac{1}{2} \frac{d[C]}{dt}$$

Q: The solubility of nitrogen gas at $$25\ ^\circ\mathrm{C}$$ and a nitrogen pressure of $$522\ \mathrm{mmHg} is$$ $$4.7 \times 10$$^{-4}$$\ \mathrm{mol/L}. $$What is the value of Henry's Law constant in $$\mathrm{mol\ L$$^{-1}$$\ $$atm^{-1}$$}$$?

$$6.8 \times 10$$^{-4}$$\ \mathrm{mol\ L$$^{-1}$$\ $$atm^{-1}$$}$$

Q: The activation energy for the decomposition of $$\mathrm{N_2O_5} is$$ $$102\ \mathrm{kJ/mol}. If$$ $$k = 1.35 \times 10$$^{-4}$$\ \mathrm{s}^{-1} at$$ $$35\ ^\circ\mathrm{C}$$, what is the value of $$k at$$ $$0\ ^\circ\mathrm{C}$$? ($$R = 8.314\ \mathrm{J/mol\ K})$$

$$8.2 \times 10$$^{-7}$$\ \mathrm{s}^{-1}$$

Question 1

Which of the following best describes the units for the rate constant $$k$$ for a second-order reaction?

Accepted Answer

$$\mathrm{L\ $$mol^{-1}$$\ s$$^{-1}$$}$$

Question 2

For the reaction $$A + 2B ightarrow 	ext{products}$$ with the rate law $$	ext{rate} = k[A][B]^2$$, if the concentration of $$B is $$doubled while $$[A]$$ remains constant, by what factor does the rate increase?

Accepted Answer

4

Question 3

Consider the reaction $$A + 3B \rightarrow 2C. $$Which of the following correctly expresses the rate in terms of the change in concentration of $$C$$?

Accepted Answer

$$	ext{rate} = \frac{1}{2} \frac{d[C]}{dt}$$

Question 4

Which of the following graphs would yield a straight line with a positive slope equal to $$k$$ for a second-order reaction?

Accepted Answer

A plot of $$1/[A]_t vs$$ $$t$$

Question 5

A first-order reaction has a rate constant $$k = 0.0447\ \mathrm{hr}^{-1}. $$What is the half-life ($$t_{1/2}) of $$the reaction?

Accepted Answer

$$t_{1/2} = \frac{0.693}{0.0447} = 15.5\ \mathrm{hr}$$

Question 6

A solution is made by dissolving $$45.0\ \mathrm{g} of$$ $$\mathrm{$$KNO_3$$} in$$ $$295\ \mathrm{mL} of $$water (density $$= 0.997\ \mathrm{g/mL}). $$What is the percent by mass of $$\mathrm{$$KNO_3$$} in $$the solution?

Accepted Answer

13.3\%

Question 7

What is the mole fraction of urea in a solution containing $$2.1$$ mol urea and $$4.4$$ mol water?

Accepted Answer

0.32

Question 8

Which of the following is NOT a colligative property?

Accepted Answer

Atmospheric pressure

Question 9

A solution is prepared by dissolving $$45.38\ \mathrm{g} of$$ $$\mathrm{$$CdBr_2$$} in$$ $$375.0\ \mathrm{g} of $$water. What is the molality of the solution? (Molar mass of $$\mathrm{$$CdBr_2$$} = 272.2\ \mathrm{g/mol})$$

Accepted Answer

0.4446\ m

Question 10

Which of the following substances is NOT soluble in water?

Accepted Answer

Vitamin E

Question 11

The solubility of nitrogen gas at $$25\ ^\circ\mathrm{C}$$ and a nitrogen pressure of $$522\ \mathrm{mmHg} is$$ $$4.7 	imes 10$$^{-4}$$\ \mathrm{mol/L}. $$What is the value of Henry's Law constant in $$\mathrm{mol\ L$$^{-1}$$\ $$atm^{-1}$$}$$?

Accepted Answer

$$6.8 	imes 10$$^{-4}$$\ \mathrm{mol\ L$$^{-1}$$\ $$atm^{-1}$$}$$

Question 12

A solution is prepared by dissolving $$42.5\ \mathrm{g} of $$barbital (MW $$= 184.2\ \mathrm{g/mol}) in$$ $$825\ \mathrm{g} of $$acetic acid. If $$K_b = 3.07\ ^\circ\mathrm{C}/m$$ and the boiling point of pure acetic acid is $$117.9\ ^\circ\mathrm{C}$$, what is the boiling point of the solution?

Accepted Answer

$$118.8\ ^\circ\mathrm{C}$$

Question 13

What is the freezing point of a solution prepared from $$50.0\ \mathrm{g}$$ ethylene glycol ($$\mathrm{C_2H_6O_2}) $$and $$85.0\ \mathrm{g}$$ water? ($$K_f of $$water $$= 1.86\ ^\circ\mathrm{C}/m)$$

Accepted Answer

$$-17.6\ ^\circ\mathrm{C}$$

Question 14

A $$0.102\ \mathrm{g}$$ sample of an unknown compound is dissolved in $$100.0\ \mathrm{mL} of $$water and has an osmotic pressure of $$28.1\ \mathrm{mmHg} at$$ $$20\ ^\circ\mathrm{C}. $$What is the molar mass of the compound? ($$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

664\ \mathrm{g/mol}

Question 15

Butadiene ($$\mathrm{C_4H_6}) $$dimerizes to $$\mathrm{C_8H_{12}}$$ with a rate law $$	ext{rate} = 0.014\ \mathrm{L/(mol\cdot s)}\ [\mathrm{C_4H_6}]^2. $$What will be the concentration of $$\mathrm{C_4H_6}$$ after $$3.0$$ hours if the initial concentration is $$0.025\ \mathrm{M}$$?

Accepted Answer

0.0052\ \mathrm{M}

Question 16

The activation energy for the decomposition of $$\mathrm{N_2O_5} is$$ $$102\ \mathrm{kJ/mol}. If$$ $$k = 1.35 	imes 10$$^{-4}$$\ \mathrm{s}^{-1} at$$ $$35\ ^\circ\mathrm{C}$$, what is the value of $$k at$$ $$0\ ^\circ\mathrm{C}$$? ($$R = 8.314\ \mathrm{J/mol\ K})$$

Accepted Answer

$$8.2 	imes 10$$^{-7}$$\ \mathrm{s}^{-1}$$

Question 17

Which of the following statements about colligative properties is TRUE?

Accepted Answer

They depend on the number of solute particles, not their identity.

Question 18

A $$17.0\% by $$mass solution of sodium acetate ($$\mathrm{CH_3COONa}$$, molar mass $$= 82.0\ \mathrm{g/mol}) in $$water has a density of $$1.09\ \mathrm{g/mL}. $$What is its molarity?

Accepted Answer

2.26\ \mathrm{M}

Question 19

A solution is prepared by dissolving $$0.75$$ mol of safrole in $$950\ \mathrm{g} of $$ethanol (MW $$= 46.07\ \mathrm{g/mol}). If $$the vapor pressure of pure ethanol at $$25\ ^\circ\mathrm{C} is$$ $$50.0$$ torr, what is the vapor pressure of the solution?

Accepted Answer

48\ \mathrm{torr}

General Chemistry Study Guide: Kinetics and Solutions

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