Q: Given the following data for the formation of $$\mathrm{LiF}$$: $$\Delta H_{\text{sublimation}} = +155.2\ \mathrm{kJ}$$ $$\Delta H_{\text{ionization}} = +520.0\ \mathrm{kJ}$$ $$\Delta H_{\text{dissociation}} = +150.6\ \mathrm{kJ}$$ $$\Delta H_{\text{electron affinity}} = -333\ \mathrm{kJ}$$ $$\Delta H_{\text{formation}} = -594.1\ \mathrm{kJ}$$ What is the lattice energy ($$\Delta H_{\text{lattice}}) $$for $$\mathrm{LiF}$$?

$$\Delta H_{\text{lattice}} = -1086.9\ \mathrm{kJ}$$

Question 1

Which of the following statements best describes a state function?

Accepted Answer

A property that depends only on the initial and final states of a system, not on the path taken.

Question 2

A sample of aluminum (Al) with a mass of 35.0 g is heated from $$55.0\ ^\circ\mathrm{C} to$$ $$75.0\ ^\circ\mathrm{C}. $$The specific heat of Al is $$0.908\ \mathrm{J}/(\mathrm{g}\cdot\mathrm{K}). $$How much heat is absorbed by the aluminum?

Accepted Answer

$$q = (35.0)(0.908)(75.0-55.0) = 636\ \mathrm{J}$$

Question 3

Which of the following best explains why water has a higher boiling point than hydrogen sulfide ($$\mathrm{H_2S}$$)?

Accepted Answer

Water forms hydrogen bonds, which are stronger than the dipole-dipole forces in $$\mathrm{H_2S}.$$

Question 4

Which process is exothermic?

Accepted Answer

Condensation of steam to liquid water

Question 5

Given the following data for the formation of $$\mathrm{LiF}$$:

$$\Delta H_{	ext{sublimation}} = +155.2\ \mathrm{kJ}$$
$$\Delta H_{	ext{ionization}} = +520.0\ \mathrm{kJ}$$
$$\Delta H_{	ext{dissociation}} = +150.6\ \mathrm{kJ}$$
$$\Delta H_{	ext{electron affinity}} = -333\ \mathrm{kJ}$$
$$\Delta H_{	ext{formation}} = -594.1\ \mathrm{kJ}$$

What is the lattice energy ($$\Delta H_{	ext{lattice}}) $$for $$\mathrm{LiF}$$?

Accepted Answer

$$\Delta H_{	ext{lattice}} = -1086.9\ \mathrm{kJ}$$

Question 6

Which of the following molecules exhibits hydrogen bonding?

Accepted Answer

$$\mathrm{CH_3OH}$$

Question 7

Which of the following ions is largest in size: $$\mathrm{Se$$^{2-}$$}$$, $$\mathrm{Br^-}$$, $$\mathrm{Rb^+}$$, or $$\mathrm{Sr$$^{2+}$$}$$?

Accepted Answer

$$\mathrm{Se$$^{2-}$$}$$

Question 8

Which of the following best describes the trend in ionization energy across a period in the periodic table?

Accepted Answer

Ionization energy increases from left to right across a period.

Question 9

Which of the following is NOT a property of gases?

Accepted Answer

Gases have a definite shape.

Question 10

Which of the following best explains why the vapor pressure of a liquid increases with temperature?

Accepted Answer

As temperature increases, more molecules have enough kinetic energy to escape the liquid phase.

Question 11

Which of the following best describes the effect of intermolecular forces on the boiling point of a liquid?

Accepted Answer

Stronger intermolecular forces result in a higher boiling point.

Question 12

Which of the following is the correct electron configuration for a neutral chlorine atom?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^5$$

Question 13

Which of the following molecules is nonpolar?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 14

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changes directly to a gas without passing through the liquid phase.

Question 15

Which of the following is true about the triple point on a phase diagram?

Accepted Answer

It is the unique set of conditions where solid, liquid, and gas phases coexist in equilibrium.

Question 16

Which of the following best explains why metals are good conductors of electricity?

Accepted Answer

Metals have a 'sea of electrons' that are free to move throughout the structure.

Question 17

Which of the following is the correct formula to calculate the heat required to raise the temperature of a substance?

Accepted Answer

$$q = m C_s \Delta T$$

Question 18

Which of the following best describes the relationship between atomic radius and effective nuclear charge across a period?

Accepted Answer

Atomic radius decreases as effective nuclear charge increases.

Question 19

Which of the following is an example of a molecule with an expanded octet?

Accepted Answer

$$\mathrm{SF_6$}$$

Question 20

Which of the following best describes the effect of surface area on the rate of evaporation of a liquid?

Accepted Answer

Increasing surface area increases the rate of evaporation.

General Chemistry Study Guide: Thermochemistry, Atomic Structure, Periodic Trends, Bonding, and States of Matter

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