Thermal Physics

Question 1

For an ideal gas, what assumption is made regarding the energy of the molecules?

Answer 1

The collision of molecules with each other and the container walls are perfectly elastic

Question 2

What is brownian motion?

Answer 2

The observable random motion of a smoke particle or pollen grain due to being bombarded by unobservable particles of gas

Question 3

What is absolute 0 in Kelvin and Celsius?

Answer 3

K = 0
C= -273

Question 4

What happens to the temperature of a substance when it changes state?

Answer 4

Remains constant

Question 5

What is assumed about the motion of molecules in an ideal gas?

Answer 5

They move in all directions with random speeds

Question 6

What is Boyle’s law?

Answer 6

For a fixed mass of gas at a constant temperature, the pressure is inversely proportional to the volume

Question 7

What is the relationship between the temperature of a gas and the kinetic energy of the molecules?

Answer 7

Directly proportinal

Question 8

What is the first law of thermodynamics?

Answer 8

The change of internal energy of an object is equal to the thermal energy added to the object

Question 9

What happens to the average kinetic and potential energies of the particles during an increase in temperature?

Answer 9

They both increase

Question 10

For an ideal gas, what assumption is made regarding the time of collision of the molecules and the wall?

Answer 10

Negligible

Question 11

What happens to the average kinetic and potential energies of the particles during a change of state?

Answer 11

Potential energy increases
kinetic remains constant

Question 12

Define molar mass

Answer 12

The mass of 1 mol of a substance

Question 13

What is Avogadro’s constant based off of?

Answer 13

the number of atoms in 12g of carbon-12

Question 14

What is meant by thermal equilibrium?

Answer 14

The net flow of energy between two objects is zero

Question 15

When does thermal equilibrium occur?

Answer 15

when the temperature of the objects is equal to

Question 16

What is meant by the internal energy of a substance?

Answer 16

The sum of the kinetic and potential energies of molecules in the substance

Question 17

Define specific latent heat of fusion

Answer 17

The amount of energy required to change the state of 1kg of a substance from a solid to a liquid

Question 18

For an ideal gas, what assumption is made regarding the volume of the molecules?

Answer 18

The molecules occupy a negligible volume compared with the volume of the gas

Question 19

For an ideal gas, what assumption is made regarding the forces between the molecules?

Answer 19

Electrostatic forces between molecules is negligible

Question 20

Define specific latent heat if vaporistaion

Answer 20

The amount of energy required to change the state of 1kg of a substance from a liquid to a gas

Question 21

Define specific heat capacity

Answer 21

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

Question 22

What does the pressure law state?

Answer 22

For a fixed mass of gas at a constant volume, the pressure is directly proportional to its absolute temperature

Question 23

Define an ideal gas

Answer 23

A theoretical gas which obeys the experimental gas laws at all pressures and temperatures

Question 24

What does Charles; law state?

Answer 24

For a fixed mass of a gas at a constant pressure, the volume of the gas is directly proportional to its absolute temperature