Question 1

Which of the following best describes the First Law of Thermodynamics?

Accepted Answer

The total energy of an isolated system is constant; energy can be transferred or transformed but not created or destroyed.

Question 2

Given the equation $\Delta E = q + w$, what does each term represent in the context of thermodynamics?

Accepted Answer

$\Delta E$ is the change in internal energy, $q$ is the heat absorbed by the system, and $w$ is the work done on the system.

Question 3

A chemical reaction occurs in a closed container, releasing 150 J of heat to the surroundings and doing 50 J of work on the surroundings. What is the change in internal energy ($\Delta E$) of the system?

Accepted Answer

$\Delta E = -100 \ \mathrm{J}$

Question 4

Which of the following statements about enthalpy ($\Delta H$) is correct?

Accepted Answer

Enthalpy is the sum of a system's internal energy and the product of its pressure and volume: $H = E + PV$.

Question 5

A reaction has an enthalpy change ($\Delta H$) of $-250 \ \mathrm{kJ}$. Which statement is true?

Accepted Answer

The reaction is exothermic and releases 250 kJ of heat.

Question 6

Which equation correctly represents the relationship between heat ($q$), mass ($m$), specific heat capacity ($c$), and temperature change ($\Delta T$)?

Accepted Answer

$q = m \cdot c \cdot \Delta T$

Question 7

A 100 g sample of water is heated from $25^\circ \mathrm{C}$ to $75^\circ \mathrm{C}$. If the specific heat capacity of water is $4.18 \ \mathrm{J/g \cdot ^\circ C}$, how much heat is absorbed?

Accepted Answer

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

Question 8

Which of the following best describes Hess's Law?

Accepted Answer

The enthalpy change of a reaction is independent of the pathway between initial and final states.

Question 9

Which of the following is the correct standard enthalpy of formation ($\Delta H_f^\circ$) for an element in its most stable form?

Accepted Answer

$\Delta H_f^\circ = 0$

Question 10

Which of the following is a correct application of the First Law of Thermodynamics to a real-world scenario?

Accepted Answer

A battery powering a flashlight converts chemical energy into light and heat, but the total energy remains constant.

Question 11

Which of the following equations represents Boyle's Law?

Accepted Answer

$P_1 V_1 = P_2 V_2$

Question 12

A sample of gas occupies 2.0 L at 1.0 atm. If the pressure is increased to 4.0 atm at constant temperature, what is the new volume?

Accepted Answer

0.5 L

Question 13

Which of the following is the correct form of the Ideal Gas Law?

Accepted Answer

$PV = nRT$

Question 14

Which assumption is NOT made in the kinetic molecular theory of gases?

Accepted Answer

Gas particles exert attractive and repulsive forces on each other.

Question 15

At STP, what is the volume occupied by 2 moles of an ideal gas?

Accepted Answer

44.8 L

Question 16

Which of the following correctly describes Charles's Law?

Accepted Answer

At constant pressure, the volume of a gas is directly proportional to its temperature in Kelvin.

Question 17

A 5.0 g sample of helium gas is placed in a 10.0 L container at 300 K. What is the pressure exerted by the gas? (Use $R = 0.0821 \ \mathrm{L \cdot atm \cdot mol^{-1} \cdot K^{-1}}$ and molar mass of He = 4.00 g/mol)

Accepted Answer

1.23 atm

Question 18

Which of the following is a correct statement about Avogadro's Law?

Accepted Answer

At constant temperature and pressure, equal volumes of gases contain equal numbers of molecules.

Question 19

Which of the following equations is used to calculate the root mean square speed ($u_{rms}$) of a gas particle?

Accepted Answer

$u_{rms} = \sqrt{\frac{3RT}{M}}$

Question 20

Which of the following best explains why real gases deviate from ideal behavior at high pressures and low temperatures?

Accepted Answer

Intermolecular forces and the finite volume of gas particles become significant.

Thermochemistry and Gas Laws: Exam Learning Objectives

Study Guide - Practice Questions

Study Guide - Flashcards