Question 1

Which of the following best describes the two major types of energy discussed in thermodynamics?

Accepted Answer

Potential energy and kinetic energy

Question 2

Which equation correctly represents the First Law of Thermodynamics for a closed system?

Accepted Answer

$$ \Delta E = q + w $$

Question 3

A chemical reaction occurs in a coffee-cup calorimeter at constant pressure. Which equation should be used to calculate the enthalpy change?

Accepted Answer

$$ \Delta H = q_p $$

Question 4

Which of the following statements about state functions is correct?

Accepted Answer

State functions depend only on the initial and final states, not on the path taken.

Question 5

Which process is exothermic?

Accepted Answer

Combustion of methane

Question 6

What is the symbol for heat in thermodynamics, and how does it relate to the sign convention?

Accepted Answer

q; positive when heat is absorbed by the system

Question 7

Which equation correctly expresses the relationship between enthalpy, internal energy, pressure, and volume?

Accepted Answer

$$ H = E + PV $$

Question 8

A gas expands against a constant external pressure. Which equation gives the work done by the system?

Accepted Answer

$$ w = -P_{ext} \Delta V $$

Question 9

Which of the following is an example of an extensive property?

Accepted Answer

Enthalpy

Question 10

Which statement best describes calorimetry?

Accepted Answer

It is the measurement of heat flow in a chemical or physical process.

Question 11

A student mixes two solutions in a calorimeter and observes a temperature increase. What does this indicate about the reaction?

Accepted Answer

The reaction is exothermic.

Question 12

Which equation is used to calculate the heat absorbed or released by a substance?

Accepted Answer

$$ q = mC\Delta T $$

Question 13

Which of the following best describes the difference between endothermic and exothermic processes?

Accepted Answer

Endothermic processes absorb heat; exothermic processes release heat.

Question 14

Which of the following is true about the enthalpy of formation ($$ \Delta H_f^\circ $$)?

Accepted Answer

It is the enthalpy change when one mole of a compound is formed from its elements in their standard states.

Question 15

Which equation represents Hess's Law for calculating the enthalpy change of a reaction?

Accepted Answer

$$ \Delta H_{rxn} = \sum \Delta H_{products} - \sum \Delta H_{reactants} $$

Question 16

A sample of water (mass = 100 g, $$ C = 4.18 	ext{ J/g} \cdot 	ext{K} ) is $$heated from 25°C to 75°C. How much heat is absorbed?

Accepted Answer

$$ q = 20,900 	ext{ J} $$

Question 17

Which of the following is NOT a guideline for calculating $$ \Delta H_{rxn} $$ using enthalpies of formation?

Accepted Answer

Ignore the physical states of reactants and products.

Question 18

Which type of calorimeter is best suited for measuring the heat of combustion reactions?

Accepted Answer

Bomb calorimeter

Question 19

Which of the following best describes an electrostatic attraction?

Accepted Answer

The force between oppositely charged particles

Question 20

A reaction has $$ \Delta H = -250 	ext{ kJ} . $$What does this value indicate?

Accepted Answer

The reaction releases 250 kJ of heat to the surroundings.

Thermodynamics and Energy in General Chemistry: Study Guide

Guida di studio - Domande di pratica