Question 1

Which of the following best describes the difference between kinetic energy and potential energy?

Accepted Answer

Kinetic energy is energy of motion, while potential energy is stored energy due to position.

Question 2

A 50.0 g block of iron at $$100\ ^\circ \mathrm{C} is $$placed in 100.0 g of water at $$20\ ^\circ \mathrm{C}. If $$the final temperature of the system is $$22\ ^\circ \mathrm{C}$$, which equation would you use to solve for the heat lost by the iron?

Accepted Answer

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

Question 3

Which statement about the conservation of energy is correct?

Accepted Answer

Energy can be converted from one form to another, but cannot be created or destroyed.

Question 4

A chemical reaction absorbs heat from the surroundings. Which term best describes this process?

Accepted Answer

Endothermic

Question 5

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

Accepted Answer

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

Question 6

A gas expands against an external pressure, doing 250 J of work and absorbing 150 J of heat. What is the change in internal energy ($$\Delta U) of $$the system?

Accepted Answer

$$\Delta U = 150\ \mathrm{J} - 250\ \mathrm{J} = -100\ \mathrm{J}$$

Question 7

Which of the following is an example of potential energy?

Accepted Answer

A stretched rubber band

Question 8

In a calorimetry experiment, 2.00 g of a substance is burned, releasing 35.0 kJ of heat. If the temperature of 500.0 g of water increases by $$16.7\ ^\circ \mathrm{C}$$, what is the specific heat capacity ($$c) of $$water?

Accepted Answer

$$c = \dfrac{35,000\ \mathrm{J}}{500.0\ \mathrm{g} \cdot 16.7\ ^\circ \mathrm{C}}$$

Question 9

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

Accepted Answer

Enthalpy change ($$\Delta H) is $$positive for endothermic reactions.

Question 10

Which formula is used to calculate the work ($$w) $$done by a gas during expansion at constant pressure?

Accepted Answer

$$w = -P \cdot \Delta V$$

Question 11

A reaction has $$\Delta H = -200\ \mathrm{kJ}. $$What does this value indicate about the reaction?

Accepted Answer

The reaction is exothermic and releases 200 kJ of heat.

Question 12

Which of the following best describes Hess's Law?

Accepted Answer

The enthalpy change of a reaction is independent of the pathway and depends only on the initial and final states.

Question 13

A student mixes 100 mL of $$1.0\ \mathrm{M}$$ HCl with 100 mL of $$1.0\ \mathrm{M}$$ NaOH in a calorimeter. The temperature rises by $$5.7\ ^\circ \mathrm{C}. If $$the specific heat of the solution is $$4.18\ \mathrm{J}/\mathrm{g}\ ^\circ \mathrm{C}$$ and the density is $$1.0\ \mathrm{g}/\mathrm{mL}$$, what is the heat released?

Accepted Answer

$$q = 200\ \mathrm{g} \cdot 4.18\ \mathrm{J}/\mathrm{g}\ ^\circ \mathrm{C} \cdot 5.7\ ^\circ \mathrm{C}$$

Question 14

Which of the following is NOT a form of energy?

Accepted Answer

Temperature

Question 15

A reaction occurs in a bomb calorimeter and the temperature of the water increases. What does this indicate about the reaction?

Accepted Answer

The reaction is exothermic.

Question 16

Which equation represents the First Law of Thermodynamics?

Accepted Answer

$$\Delta U = q + w$$

Question 17

A student wants to determine the enthalpy change for the formation of water using Hess's Law. Which approach should they use?

Accepted Answer

Add the enthalpy changes of known reactions that sum to the formation of water.

Question 18

Which of the following is a real-life example of the conversion of potential energy to kinetic energy?

Accepted Answer

A ball rolling down a hill

Question 19

If a reaction has $$\Delta H = +50\ \mathrm{kJ}$$, what can be inferred about the heat flow?

Accepted Answer

Heat is absorbed from the surroundings.

Energy and Thermochemistry: Study Notes

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