$\text{Efficiency} = \dfrac{\text{Energy Used from Fuel}}{\text{Energy Contained in Fuel}} \times 100\%$

Question 1

Which statement best describes the First Law of Thermodynamics?

Accepted Answer

Energy is not created or destroyed, but is converted from one form to another.

Question 2

A hot metal rod is placed in contact with a cold metal rod. According to the Second Law of Thermodynamics, what will happen?

Accepted Answer

Heat will flow from the hot rod to the cold rod until thermal equilibrium is reached.

Question 3

Which of the following is an example of convection?

Accepted Answer

Warm air rising above a radiator and circulating in a room.

Question 4

What are the products of the complete combustion of a hydrocarbon fuel?

Accepted Answer

$\mathrm{CO_2}$ and $\mathrm{H_2O}$

Question 5

Which equation correctly represents the complete combustion of methane ($\mathrm{CH_4}$)?

Accepted Answer

$\mathrm{CH_4} + 2\mathrm{O_2} \rightarrow \mathrm{CO_2} + 2\mathrm{H_2O}$

Question 6

Why was tetraethyl lead removed from gasoline?

Accepted Answer

It was found to be toxic to humans and the environment.

Question 7

Which of the following best describes an exothermic reaction?

Accepted Answer

A reaction that releases heat to the surroundings.

Question 8

What is the main reason heat engines cannot be 100% efficient?

Accepted Answer

The Second Law of Thermodynamics dictates that some energy is always lost as waste heat.

Question 9

Which fossil fuel is primarily composed of methane?

Accepted Answer

Natural Gas

Question 10

Fractional distillation of petroleum separates components based on which property?

Accepted Answer

Boiling point

Question 11

A gasoline engine has a compression ratio of 10:1. What does this mean?

Accepted Answer

The volume after maximum compression is 1/10th the volume before compression.

Question 12

Which of the following is a correct formula for calculating the efficiency of a heat engine?

Accepted Answer

$	ext{Efficiency} = \dfrac{	ext{Energy Used from Fuel}}{	ext{Energy Contained in Fuel}} 	imes 100\%$

Question 13

Which process is primarily responsible for the transfer of heat from the Sun to the Earth?

Accepted Answer

Radiation

Question 14

If the incomplete combustion of a hydrocarbon occurs, which toxic gas is likely to be produced?

Accepted Answer

$\mathrm{CO}$

Question 15

Which of the following best explains why living things must use energy to stay alive?

Accepted Answer

To maintain order and fight the natural tendency toward increased entropy.

Question 16

Which of the following statements about octane rating is correct?

Accepted Answer

A higher octane rating means the fuel resists pre-ignition better.

Question 17

Which of the following is NOT a fossil fuel?

Accepted Answer

Ethanol

Question 18

Which of the following best describes the role of an octane booster in gasoline?

Accepted Answer

It increases the resistance of gasoline to pre-ignition (knocking).

Question 19

Which of the following is a correct statement about the energy released during combustion?

Accepted Answer

The energy released is the excess bond energy after both breaking and forming bonds.

Question 20

A heat engine operates at 50% efficiency. If 1000 kJ of energy is contained in the fuel, how much energy is converted to useful work?

Accepted Answer

500 kJ

Energy, Thermodynamics, and Fuels: Study Notes for Introductory Chemistry

Study Guide - Practice Questions