Q: A sample of gas has a pressure of $$2.00\ \mathrm{atm}$$, a volume of $$5.00\ \mathrm{L}$$, and a temperature of $$300\ \mathrm{K}. $$How many moles of gas are present? ($$R = 0.0821\ \mathrm{L} \cdot \mathrm{atm} / \mathrm{mol} \cdot \mathrm{K})$$

$$n = \dfrac{PV}{RT} = \dfrac{2.00 \times 5.00}{0.0821 \times 300} \approx 0.41$$

Question 1

Which of the following best describes the process of oxidation in a redox reaction?

Accepted Answer

Loss of electrons by a species

Question 2

A sample of gas at STP occupies 22.4 L. If the sample contains 2 moles of gas, what is its volume?

Accepted Answer

$$44.8\ \mathrm{L}$$

Question 3

Which of the following is NOT a state function?

Accepted Answer

Work ($$w)$$

Question 4

According to Dalton’s Law of Partial Pressures, what is the total pressure exerted by a mixture of gases?

Accepted Answer

The sum of the partial pressures of each gas

Question 5

Which equation is used to relate the pressure, volume, and temperature of an ideal gas?

Accepted Answer

$$PV = nRT$$

Question 6

A chemical reaction has $$\Delta H = -150\ \mathrm{kJ}. $$Which statement is true?

Accepted Answer

The reaction is exothermic and releases heat

Question 7

Which of the following best explains why the internal energy change ($$\Delta U) of a $$system is a state function?

Accepted Answer

It depends only on the initial and final states, not the path taken

Question 8

A balloon expands against a constant external pressure of $$1.00\ \mathrm{atm}$$ from $$2.00\ \mathrm{L} to$$ $$5.00\ \mathrm{L}. $$What is the work done by the system?

Accepted Answer

$$w = -3.00\ \mathrm{L} \cdot \mathrm{atm}$$

Question 9

Which statement about Graham’s Law of Effusion is correct?

Accepted Answer

The rate of effusion of a gas is inversely proportional to the square root of its molar mass

Question 10

Which of the following is the correct expression for calculating heat ($$q) $$absorbed by a substance when its temperature changes?

Accepted Answer

$$q = mC\Delta T$$

Question 11

A sample of gas has a pressure of $$2.00\ \mathrm{atm}$$, a volume of $$5.00\ \mathrm{L}$$, and a temperature of $$300\ \mathrm{K}. $$How many moles of gas are present? ($$R = 0.0821\ \mathrm{L} \cdot \mathrm{atm} / \mathrm{mol} \cdot \mathrm{K})$$

Accepted Answer

$$n = \dfrac{PV}{RT} = \dfrac{2.00 	imes 5.00}{0.0821 	imes 300} \approx 0.41$$

Question 12

Which of the following is true about endothermic reactions?

Accepted Answer

They absorb heat from the surroundings

Question 13

Which law states that the total energy of an isolated system is constant?

Accepted Answer

First Law of Thermodynamics

Question 14

If the rate of effusion of gas 1 is twice that of gas 2, what is the ratio of their molar masses ($$M_1$$ and $$M_2$$)?

Accepted Answer

$$M_2 = 4M_1$

Question 15

Which of the following is the correct form of the van der Waals equation for real gases?

Accepted Answer

$$\left(P + \dfrac{a n^2$}{V^2$}\right)(V - nb) = nRT$$

Question 16

Which statement best describes Boyle’s Law?

Accepted Answer

At constant temperature, the pressure of a gas is inversely proportional to its volume

Question 17

Which of the following is the correct relationship for calculating enthalpy change ($$\Delta H) $$using constant pressure calorimetry?

Accepted Answer

$$q_{p} = \Delta H$$

Question 18

A reaction has $$\Delta H = +75\ \mathrm{kJ}$$ and $$\Delta S = +200\ \mathrm{J}/\mathrm{K}. At $$what temperature will the reaction become spontaneous? ($$\Delta G = \Delta H - T\Delta S)$$

Accepted Answer

$$T \u003e 375\ \mathrm{K}$$

Question 19

Which of the following is a correct application of Hess’s Law?

Accepted Answer

The enthalpy change of a reaction is independent of the pathway taken

General Chemistry Exam Study Guide: Thermodynamics, Gas Laws, and Chemical Reactions

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