Question 1

Which of the following phase changes is associated with a positive change in both enthalpy ($$\Delta H) $$and entropy ($$\Delta S$$)?

Accepted Answer

Vaporization

Question 2

A sample of water is heated from $$-10^\circC to$$ $$110^\circC at 1 $$atm. Which of the following steps requires the greatest amount of energy per mole?

Accepted Answer

Vaporizing water at $$100^\circC$$

Question 3

Which of the following statements about the boiling point of a liquid is correct?

Accepted Answer

It is the temperature at which the vapor pressure equals atmospheric pressure.

Question 4

Given the following data for a liquid: $$\Delta H_{vap} = 40.7 kJ/$$mol, $$P_{vap,1} = 0.0409$$ atm at $$T_1 = 273$ K, calculate the vapor pressure at T_2$ = 298 K $$using the Clausius-Clapeyron equation.

Accepted Answer

$$P_{vap,2} \approx 0.123$$ atm

Question 5

Which of the following best describes the structure of diamond?

Accepted Answer

Each carbon atom is bonded to four others in a tetrahedral network.

Question 6

A face-centered cubic (fcc) unit cell contains how many atoms per unit cell?

Accepted Answer

4

Question 7

Which of the following statements about semiconductors is true?

Accepted Answer

Their electrical conductivity increases with increasing temperature.

Question 8

Which of the following solutions will have the highest boiling point, assuming complete dissociation?

Accepted Answer

0.10 m CaCl$$_2$$

Question 9

A solution is prepared by dissolving 10.0 g of NaCl (molar mass = 58.44 g/mol) in 500.0 g of water. What is the molality of the solution?

Accepted Answer

0.171 m

Question 10

Which of the following best explains why gases are less soluble in liquids at higher temperatures?

Accepted Answer

The increased temperature increases the tendency of gas molecules to escape into the vapor phase.

Question 11

Which of the following is the correct expression for the rate of the reaction $$2A + B \rightarrow 3C$$?

Accepted Answer

$$r = -\frac{1}{2} \frac{d[A]}{dt} = -\frac{d[B]}{dt} = \frac{1}{3} \frac{d[C]}{dt}$$

Question 12

For a first-order reaction, what fraction of the initial reactant remains after three half-lives?

Accepted Answer

$$\frac{1}{8}$$

Question 13

Which of the following statements about catalysts is correct?

Accepted Answer

A catalyst lowers the activation energy of a reaction.

Question 14

Which of the following is a correct statement about the triple point of a substance?

Accepted Answer

It is the temperature and pressure at which all three phases coexist in equilibrium.

Question 15

Which of the following best describes the effect of n-type doping in a semiconductor?

Accepted Answer

It introduces extra electrons into the conduction band.

Question 16

A reaction has a rate constant $$k = 2.5 	imes 10$$^{-3}$$ s$$^{-1}$$ at 300 K and k = 7.5$$ 	imes $$10^{-3} s$^{-1} at 320 K. $$Using the two-point Arrhenius equation, what is the activation energy $$E_a in kJ/$$mol? ($$R = 8.314 J/($$mol·K))

Accepted Answer

$$E_a \approx 27.1 kJ/$$mol

Question 17

Which of the following is a colligative property?

Accepted Answer

Boiling point elevation

Question 18

Which of the following best explains why water has a higher boiling point than methane ($$CH_4$$)?

Accepted Answer

Water has stronger hydrogen bonding between molecules.

Question 19

Which of the following is true about the entropy of a substance in different phases?

Accepted Answer

$$S_{solid} \u003c S_{liquid} \u003c S_{gas}$$

General Chemistry II: Study Guide for Chapters 11–14

Study Guide - Practice Questions

Study Guide - Flashcards