Question 1

A 10.0 g sample of calcium reacts with excess hydrochloric acid according to the equation: $$\mathrm{Ca(s) + 2HCl(aq) \rightarrow $$CaCl_2$$(aq) + H_2$(g)}. $$What is the theoretical yield of hydrogen gas (in grams) produced?

Accepted Answer

2.80 g

Question 2

Which of the following statements best distinguishes between enthalpy ($$\Delta H$$), heat ($$q$$), and temperature ($$T$$)?

Accepted Answer

Enthalpy is the total heat content of a system at constant pressure, heat is energy transferred due to temperature difference, and temperature is a measure of average kinetic energy.

Question 3

A sample of gas occupies 4.00 L at 1.00 atm and 300 K. What will be its volume at 2.00 atm and 400 K? (Assume ideal gas behavior.)

Accepted Answer

$$3.00\ \mathrm{L}$$

Question 4

Which of the following compounds exhibits hydrogen bonding as its strongest intermolecular force?

Accepted Answer

$$\mathrm{H_2O}$$

Question 5

A solution is prepared by dissolving 10.0 g of NaCl in enough water to make 250.0 mL of solution. What is the molarity of the solution? ($$\mathrm{NaCl}$$ molar mass = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$0.684\ \mathrm{M}$$

Question 6

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changes directly to a gas; this process is endothermic.

Question 7

Which of the following statements about the kinetic molecular theory is correct?

Accepted Answer

The average kinetic energy of gas particles is directly proportional to the absolute temperature.

Question 8

A 0.100 M solution of acetic acid ($$\mathrm{CH_3COOH}$$, $$K_a = 1.8 	imes 10$$^{-5}$$) is prepared. What is the pH of the solution?

Accepted Answer

2.87

Question 9

Which of the following is the correct equilibrium expression for the reaction: $$\mathrm{N_2$(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)}$$?

Accepted Answer

$$K_c = \dfrac{[NH_3$]^2}{[N_2$][H_2$]^3}$$

Question 10

A 50.0 mL sample of 0.200 M HCl is titrated with 0.100 M NaOH. What volume of NaOH is required to reach the equivalence point?

Accepted Answer

$$100.0\ \mathrm{mL}$$

Question 11

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

Accepted Answer

Water forms hydrogen bonds, which are stronger than the London dispersion forces in methane.

Question 12

A sample of gas at 25.0 $$^\circC $$and 1.00 atm has a volume of 10.0 L. How many moles of gas are present? ($$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$0.409\ \mathrm{mol}$$

Question 13

Which of the following solutions will have the lowest freezing point? (Assume all are aqueous and fully dissociate.)

Accepted Answer

0.10 m $$\mathrm{$$CaCl_2$$}$$

Question 14

Which of the following is a correct statement about the relationship between vapor pressure and temperature?

Accepted Answer

Vapor pressure increases as temperature increases.

Question 15

A reaction has a $$\Delta H = -250\ \mathrm{kJ}. $$Which of the following statements is true?

Accepted Answer

The reaction is exothermic and releases 250 kJ of heat.

Question 16

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of NaOH and HCl?

Accepted Answer

$$\mathrm{H^+ (aq) + OH^- (aq) \rightarrow H_2O (l)}$$

Question 17

A 100.0 g sample of water at $$25.0\ ^\circ\mathrm{C} is $$heated to $$75.0\ ^\circ\mathrm{C}. If $$the specific heat of water is $$4.18\ \mathrm{J/g\ ^\circ C}$$, how much heat is absorbed?

Accepted Answer

$$20,900\ \mathrm{J}$$

Question 18

Which of the following best describes the effect of increasing the pressure on a gas at constant temperature (according to Boyle’s Law)?

Accepted Answer

The volume of the gas decreases.

Question 19

Which of the following is a Bronsted-Lowry base?

Accepted Answer

$$\mathrm{NH_3$}$$, because it accepts a proton.

Comprehensive Study Guide: Chemistry Final Exam (Chapters 8–15)

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