Thermal

Question 1

What is heat?

Answer 1

The total kinetic energy within a system.

Question 2

What is temperature?

Answer 2

The average kinetic energy of a particle within a system.

Question 3

What is specific heat capacity?

Answer 3

The amount of energy needed to raise 1kg of a substance of 1 degree Celsius.

Question 4

What is specific latent heat?

Answer 4

The amount of energy to change state of 1kg of a substance

Question 5

What is brownian motion?

Answer 5

Movement of gas is random with random velocities.

Question 6

What is proven by brownian motion?

Answer 6

atoms/observed particles are very small and their motion is random.

Question 7

What are the gas laws?

Answer 7

Pressure law - Pressure is directly proportional to temperature (K)

Boyle’s Law - Pressure is directly proportional to 1/Volume, Temperature is constant.

Charles’s Law - Volume is directly proportional to temperature (K)

Question 8

What is an isothermal process?

Answer 8

A process where temperature is constant.

Question 9

What are the properties of ideal gasses?

Answer 9

• Particles occupy negligible volume compared to the volume of gas.
• Molecules are identical in mass and speed.
• Molecules collide with each other and the walls in a perfectly elastic matter in zero time.
• Molecules exert no force on each other except during collisions.
• There are enough molecules so that statistics can be applied.
• They are moving randomly and rapidly.

Question 10

What is internal energy?

Answer 10

Sum of potential and kinetic energy.

Question 11

How does a gas exert pressure on the walls of the container?

Answer 11

• Lots of molecules collide with the walls.
• Molecules change momentum
• Newton’s second law - resultant force is the rate of change of momentum therefore a force is exerted on the wall.

Question 12

How to derive the relationship between absolute temperature and mean kinetic temperature?

Answer 12

PV = 1/3*Nmc^2
3PV = Nmc^2
KE = 1/2Mc^2
M = Nm
N = number of moles
m = Molar mass

2KE = Nmc^2
3PV = 2KE
3/2PV = KE
PV = KT for for one mol of gas
KE = 3/2kT
1/2mc^2 = 3/2kT

Question 13

Kinetic Theory for solids

Answer 13

• Strong forces of attraction
• Particles tightly packed
• Vibrate about fixed positions
• High density

Question 14

Kinetic Theory for liquids

Answer 14

• Medium forces of attraction
• Particles close
• Particles slide past each other
• Medium density
• Translational kinetic energy

Question 15

Kinetic Theory for gas

Answer 15

• Almost no attractive forces
• Particles far apart (unless compressed)
• Free to move around quickly, randomly
• Low density, compressible

Question 16

What is N?

Answer 16

Number of particles

Question 17

What is n?

Answer 17

Number of moles.

Question 18

What is the equation for the mass of an element?

Answer 18

M*n = m (in grams)

M = molar mass
n = number of mols

Question 19

How do I calculate the energy supplied for an object to change state into liquid then into gas?

Answer 19

E = mc/\T + mL(fusion) + mc/\T + mL(vapourisation)

Question 20

What happens to the maxwell-boltzmann curve when temperature is increased to an ideal gas?

Answer 20

Gases with higher temperatures have more particles with higher speeds. Therefore, peak of curve drops but curve is much less steep slope.

Question 21

What is a boltzmann distribution curve?

Answer 21

Number of molecules against energy.