B.1 Thermal energy transfers

Question 1

Temperature

Answer 1

A measure of the average random kinetic energy of the molecules in the object

Question 2

Is Temperature Scalar or Vector?

Answer 2

Scalar

Question 3

What happens at 0K/ absolute zero

Answer 3

All the molecules of a substance have stopped moving, their kinetic energy is zero. Therefore kelvin cannot have negative values.

Question 4

Internal Energy

Answer 4

The total of the intermolecular potential energy and the total random kinetic energy.

Question 5

What is Intermolecular Potential Energy due to.

Answer 5

The forces between the molecules. As distance between particles are inc/dec by adding/taking heat the intermolecular potential energy will inc/dec

Question 6

What is the total random kinetic energy of the molecules due to?

Answer 6

The particles random motion. Heating inc kinetic energy. Kinetic energy can be translational or rotational.

Question 7

Translational Kinetic Energy

Answer 7

Whole molecules moving in a certain direction

Question 8

Rotational Kinetic Energy

Answer 8

Molecules rotating about an axis

Question 9

What will happen if two objects are in thermal contact?

Answer 9

Transfer of energy will occur until they reach a thermal equilibrium (they have reached the same temp)

Question 10

What is the direction of energy transfer between hot and cold objects.

Answer 10

The hot object will lose internal energy to the cold object.

Question 11

Thermal energy or Heat (Q)

Answer 11

The energy being transferred between hot and cold objects?

Question 12

Motion of molecules in a solid

Answer 12

vibrating about a mean position

Question 13

Motion of molecules in a liquid

Answer 13

vibrating but no longer around a fixed position

Question 14

Motion of molecules in a gas

Answer 14

independent

Question 15

Solid–>Liquid

Answer 15

Melting

Question 16

Liquid–>Gas

Answer 16

Boiling

Question 17

Gas–>Liquid

Answer 17

Condensing

Question 18

Liquid–>Solid

Answer 18

Freezing

Question 19

Solid–>Gas

Answer 19

Sublimation

Question 20

Gas–>Solid

Answer 20

Deposition

Question 21

Where does boiling take place?

Answer 21

Throughout liquid

Question 22

Where does Evaporation take place?

Answer 22

At the surface of a liquid. Greater surface area=greater rate of evaporation

Question 23

What is density determined by?

Answer 23

The size and arrangement of molecules in a substance

Question 24

Specific heat capacity

Answer 24

The amount of energy required to raise the temperature of the unit mass of a substance by 1K.

Question 25

Why do different substances have different specific heat capacities?

Answer 25

Different substances have different molecular structures, forces between molecules and/or atoms and different densities.

Question 26

Specific Latent Heat

Answer 26

The amount of energy per unit mass of a substance absorbed or released during a change of phase without a change in temperature.

Question 27

What are the units for specific latent heat?

Answer 27

Jkg^-1

Question 28

Latent heat of fusion

Answer 28

Solid<–>Liquid

Question 29

Latent heat of vaporisation

Answer 29

Liquid<–>Gas

Question 31

Why does the temperature of a substance not change when a substance changes phase?