Question 1

Which of the following best describes the velocity distribution of gas molecules at high temperature according to the Maxwell-Boltzmann distribution?

Accepted Answer

The distribution shifts to higher velocities and becomes broader, with more molecules having higher speeds.

Question 2

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

Accepted Answer

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

Question 3

A sample of oxygen gas ($$O_2) $$and a sample of hydrogen gas ($$H_2) $$are at the same temperature. Which statement is true about their average molecular speeds?

Accepted Answer

Hydrogen molecules move faster than oxygen molecules because they are lighter.

Question 4

Which of the following is a correct statement about effusion rates according to Graham's law?

Accepted Answer

The rate of effusion is inversely proportional to the square root of the molar mass.

Question 5

Under which conditions do real gases most significantly deviate from ideal gas behavior?

Accepted Answer

Low temperature and high pressure.

Question 6

Which factor does the van der Waals equation take into account that the ideal gas law does not?

Accepted Answer

Intermolecular attractions and the finite volume of gas molecules.

Question 7

Which of the following is the correct expression for the first law of thermodynamics?

Accepted Answer

$$\Delta E = q + w$$

Question 8

A system absorbs 150 J of heat and does 40 J of work on the surroundings. What is the change in internal energy ($$\Delta E) of $$the system?

Accepted Answer

$$\Delta E = 110 	ext{ J}$$

Question 9

Which of the following statements best describes the difference between specific heat ($$c_s) $$and heat capacity ($$C$$)?

Accepted Answer

Specific heat is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius, while heat capacity is the amount of heat required to raise the temperature of an entire object by one degree Celsius.

Question 10

If a substance has a high specific heat, what does this imply about its ability to change temperature?

Accepted Answer

It requires a large amount of heat to change its temperature.

Question 11

Which formula is used to calculate the heat ($$q) $$absorbed or released by a substance when its temperature changes?

Accepted Answer

$$q = m c_s \Delta T$$

Question 12

In a coffee-cup calorimeter experiment, which assumption is commonly made about the solution?

Accepted Answer

The solution has a density and specific heat capacity close to those of water.

Question 13

A bomb calorimeter contains 1.00 g of a substance that releases 500 J of heat upon combustion. If the calorimeter has a heat capacity of 10 J/°C, what is the temperature change ($$\Delta T) of $$the calorimeter?

Accepted Answer

$$\Delta T = 50 	ext{°C}$$

Question 14

Given the reaction $$2 	ext{H}_2 + 	ext{O}_2 ightarrow 2 	ext{H}_2	ext{O}$$ with $$\Delta H = -572 	ext{ kJ}$$, how much energy is released when 4.0 g of $$	ext{H}_2$$ reacts completely?

Accepted Answer

$$-572 	ext{ kJ}$$

Question 15

Which of the following correctly describes how to use Hess's Law to determine the enthalpy change ($$\Delta H) $$for a reaction?

Accepted Answer

Add the $$\Delta H$$ values of known reactions after rearranging and reversing them as needed to match the target reaction.

Question 16

Which of the following is NOT a type of potential energy discussed in chemistry?

Accepted Answer

Thermal energy due to molecular motion.

Question 17

A gas sample effuses through a small hole. If the molar mass of gas A is 16 g/mol and gas B is 64 g/mol, what is the ratio of their effusion rates ($$	ext{rate}_A / 	ext{rate}_B$$)?

Accepted Answer

$$2$$

Question 18

Which of the following best explains why gases exhibit nonideal behavior at low temperatures?

Accepted Answer

Intermolecular attractions become significant, causing the gas molecules to slow down and occupy less volume than predicted by the ideal gas law.

Quiz 6 Things to Know

Guida di studio - Domande di pratica

Study guide - Flashcard