Thermochemistry I: Vocabulary

Question 1

What is thermodynamics?

Answer 1

Thermodynamics is the study of energy and its interconversions.

Question 2

What is the 0th Law of Thermodynamics?

Answer 2

The 0th Law of Thermodynamics states that when two objects are in thermal contact of one another, heat will flow from the warmer object to the cooler one. If no heat flows between them, they must remain the same temperature.

Question 3

What is the 1st Law of Thermodynamics?

Answer 3

The 1st Law of Thermodynamics states that the total energy of the universe is constant, and although energy can be converted from one form to another, energy cannot be created nor destroyed. It is often stated as the “law of conservation of energy”.

Question 4

What is energy?

Answer 4

Energy is the capacity to do work or to produce heat.

Question 5

What is potential energy?

Answer 5

Potential energy is the energy of an object due to its position or composition.

Question 6

What is kinetic energy?

Answer 6

Kinetic energy is the energy of an object due to its motion.

Question 7

What is thermal energy?

Answer 7

Thermal energy is the total kinetic energy associated with the random motions of the particles in a system.

Question 8

What is heat?

Answer 8

Heat is the transfer of thermal energy between two objects due to a temperature difference.

Question 9

What is temperature?

Answer 9

Temperature is the measure of the average kinetic energy of the random motions of particles in a system.

Question 10

What is thermal equilibrium?

Answer 10

If there is no heat flow between two objects that are in direct physical contact with one another, they are stated to be in thermal equilibrium with one another.

Question 11

What is a calorie (cal)?

Answer 11

A calorie is a unit of energy. One calorie can be defined as the energy it takes to heat one gram of H2O one degree Celsius.

Question 12

What is a joule (J)?

Answer 12

The joule is the SI unit for energy.

Question 13

What is specific heat capacity (Cs)?

Answer 13

The specific heat capacity of a substance is the energy required to raise the temperature of one gram of the substance by one degree Celsius.

Question 14

What is a system?

Answer 14

The system is the specific part of the universe that is being studied.

Question 15

What are the surroundings?

Answer 15

The surroundings are everything that is not part of the system being observed.

Question 16

What does it mean if a system is exothermic?

Answer 16

An exothermic system occurs when heat is flowing out of the system.

Question 17

What does it mean if a system is endothermic?

Answer 17

An endothermic system occurs when heat is flowing into the system.

Question 18

What is the molar heat of fusion?

Answer 18

The molar heat of fusion is the quantity of heat (in kJ) required to melt or freeze one mole of a substance at its melting point.

Question 19

What is the molar heat of vaporization?

Answer 19

The molar heat of vaporization is the quantity of heat (in kJ) required to vaporize or condense one mole of a substance at its boiling point.