Q: Which of the following is the correct calculation for the work done by a gas that expands from 2.00 L to 5.00 L against a constant external pressure of 1.50 atm? (1 L·atm = 101.3 J)

$$w = -P_{ext} \Delta V = -1.50\ \mathrm{atm} \times (5.00 - 2.00)\ \mathrm{L} = -4.50\ \mathrm{L\cdot atm} = -456\ \mathrm{J}$$

Question 1

A solution is prepared by dissolving 10.0 g of NaCl in enough water to make 500.0 mL of solution. What is the molarity of the solution? (Molar mass of NaCl = 58.44 g/mol)

Accepted Answer

$$0.342\ \mathrm{M}$$

Question 2

Which of the following compounds will form a precipitate when mixed with a solution of $$\mathrm{$$AgNO_3$$}$$?

Accepted Answer

$$\mathrm{NaCl}$$

Question 3

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of $$\mathrm{Na_2SO_4}$$ and $$\mathrm{$$BaCl_2$$}$$?

Accepted Answer

$$\mathrm{Ba$$^{2+}$$(aq) + SO_4$^{2-}(aq) \rightarrow $$BaSO_4$$(s)}$$

Question 4

A 25.0 mL sample of $$0.100\ \mathrm{M}$$ HCl is titrated with $$0.200\ \mathrm{M}$$ NaOH. What volume of NaOH is required to reach the equivalence point?

Accepted Answer

$$12.5\ \mathrm{mL}$$

Question 5

Which of the following statements about strong and weak acids is correct?

Accepted Answer

A strong acid completely ionizes in water, while a weak acid only partially ionizes.

Question 6

Which of the following is the correct balanced equation for the neutralization reaction between H$$_2SO$_4$$ and NaOH?

Accepted Answer

$$\mathrm{H_2SO_4(aq) + 2NaOH(aq) \rightarrow 2H_2O(l) + Na_2SO_4(aq)}$$

Question 7

A sample of gas has a volume of $$2.00\ \mathrm{L} at a $$pressure of $$1.00\ \mathrm{atm}. If $$the pressure is increased to $$2.50\ \mathrm{atm} at $$constant temperature, what is the new volume?

Accepted Answer

$$0.800\ \mathrm{L}$$

Question 8

Which of the following best describes the role of the oxidizing agent in a redox reaction?

Accepted Answer

It gains electrons and is reduced.

Question 9

A 2.00 L container holds $$0.500\ \mathrm{mol} of O$_2$$ gas at $$27.0^\circ\mathrm{C}. $$What is the pressure of the gas? ($$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$6.15\ \mathrm{atm}$$

Question 10

Which of the following statements about exothermic and endothermic reactions is correct?

Accepted Answer

Exothermic reactions have $$\Delta H \u003c 0$$ and release heat to the surroundings.

Question 11

A sample of gas at $$25^\circ\mathrm{C}$$ and $$1.00\ \mathrm{atm}$$ has a density of $$1.25\ \mathrm{g/L}. $$What is the molar mass of the gas? ($$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$30.6\ \mathrm{g/mol}$$

Question 12

Which of the following is the correct expression for the heat absorbed by a solution in a coffee-cup calorimeter?

Accepted Answer

$$q_{solution} = mc\Delta T$$

Question 13

Which of the following is the correct formation reaction for CO$$_2(g$$)?

Accepted Answer

$$\mathrm{C(s) + O_2$(g) \rightarrow CO_2$(g)}$$

Question 14

A reaction has $$\Delta H = -250\ \mathrm{kJ}. $$Which statement is true?

Accepted Answer

The reaction is exothermic and releases 250 kJ of heat.

Question 15

Which of the following best describes the relationship between the molar mass of a gas and its average molecular speed at a given temperature?

Accepted Answer

Gases with lower molar mass have higher average molecular speeds.

Question 16

A 100.0 mL sample of $$0.500\ \mathrm{M}$$ NaOH is diluted to a final volume of 250.0 mL. What is the new concentration?

Accepted Answer

$$0.200\ \mathrm{M}$$

Question 17

Which of the following is the correct net ionic equation for the reaction of HCl(aq) with NaOH(aq)?

Accepted Answer

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

Question 18

Which of the following is the correct calculation for the work done by a gas that expands from 2.00 L to 5.00 L against a constant external pressure of 1.50 atm? (1 L·atm = 101.3 J)

Accepted Answer

$$w = -P_{ext} \Delta V = -1.50\ \mathrm{atm} 	imes (5.00 - 2.00)\ \mathrm{L} = -4.50\ \mathrm{L\cdot atm} = -456\ \mathrm{J}$$

Question 19

Which of the following is the correct application of Dalton's Law of Partial Pressures for a mixture of three gases with partial pressures $$P_1$$, $$P_2$$, and $$P_3$$?

Accepted Answer

$$P_{total} = P_1$ + P_2$ + P_3$

General Chemistry II: Exam 2 Study Guide – Solutions, Gases, Redox, and Thermochemistry

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