Thermal

Question 1

What’s a closed system?

Answer 1

System where no transfer of matter

Question 2

When is internal energy constant?

Answer 2

When heating isn’t changed

Question 3

What does increases in temperature equal?

Answer 3

Increase in internal energy

Question 4

What does boyles law state?

Answer 4

At constant temp, pressure and volume of a gas are inversely proportional (pv is constant)

Question 5

What does Charles law state?

Answer 5

At constant pressure, volume of a gas is directly proportional to its absolute temperature (V/T is constant)

Question 6

What does pressure law state?

Answer 6

At constant volume, pressure of an ideal gas is directly proportional to its absolute temperature (P/T is constant)

Question 7

What does number of molecules (N) equal?

Answer 7

N = n x Na

Question 8

What does K equal?

Answer 8

K = R/Na

Question 9

What is the area under a PV graph?

Answer 9

Work done for a gas to expand/contract

Question 10

What is Brownian motion?

Answer 10

The random zigzag motion of an object suspended in a fluid

Question 11

What is specific heat capacity?

Answer 11

The amount of energy needed to raise the temperature of a 1kg of a substance by 1k without changing its state

Question 12

What is specific latent heat?

Answer 12

The energy needed to be gained/lost to change the state of 1kg of a substance without changing its temperature

Question 13

Heat transfer?

Answer 13

Hot to cold (particles with more energy transfer it to ones with less
Higher temp difference = faster transfer

Question 14

What changes or stays constant when changing state?

Answer 14

KE is constant by potential energy changes (bonds broken = potential increases)

Question 15

What are the assumptions in kinetic theory?

Answer 15

• molecules have negligible volume compared to the volume of the container
• Newtonian laws apply
• force acting in a collision acts for a small time compared to the time between collisions
• collisions are perfectly elastic
• all molecules are identical
• molecules move with random motion
• molecules move in straight lines between collisions
• the gas contains lots of molecules

Question 16

What is the root mean square speed?

Answer 16

The typical speed of molecules

Question 17

Learn derivation for ideal gas pressure and kinetic energy

Answer 17

Have fun wanker

Question 18

What happens if temp increases?

Answer 18

Average speed increases, increasing rate of change of momentum of molecules colliding with the container, increasing the force on walls

Question 19

What happens if temp increases at constant volume?

Answer 19

Pressure increases because:

1) the number of collisions increases
2) larger change in momentum and therefore larger force on walls

Question 20

What happens if temp increases at fixed pressure?

Answer 20

Volume increases because:

1) larger volume means greater time between collisions and so rate of change of momentum and force on walls increases
2) therefore volume increases and so surface area increases. The increase in area stops pressure increases

Question 21

Appreciate development of gas theories

Answer 21

1) Greeks has similar ideas about gases
2) then boyles law
3) then Charles law
4) pressure law discovered (amontons)
5) boyles law explained by Bernoulli
6) 1827, Brownian motion