# Thermal Physics and Gases Revision Questions

HideShow resource information
• Created by: Lizzy Day
• Created on: 25-06-16 17:18
How do you convert from celsius to kelvin?
K = C + 273
1 of 26
What is Boyle's Law?
At a constant temperature, the pressure P and volume V of a gas are inversely proportional. pV = constant. p = 1/V
2 of 26
What is Charles' Law?
At constant pressure, the volume V of a gas is directly proportional to its absolute temperature T. V/T = constant.
3 of 26
What is the 'pressure law'?
At constant volume, the pressure p of a gas is directly proportional to its absolute temperature T. P/T = constant.
4 of 26
Avogadro constant, Na, is defined as the number of atoms in exactly 12g of the carbon isotope C-12.
5 of 26
What is the Molar Mass?
The mass that 1 mole of the substance would have, and is relative to its atomic or molecular mass.
6 of 26
What is a mole?
An amount of substance containing Na particles, all of which are identical.
7 of 26
What is the ideal gas equation?
pV = nRT
8 of 26
What is the molar gas constant?
R = molar gas constant = 8.31 JK-1 mol-1 (gas constant for one mole of gas)
9 of 26
What is the ideal gas equation for gas molecules?
pV = NkT
10 of 26
What is Boltzmann's constant?
The gas constant for one molecule of gas. k = 1.38 x 10-23 JK-1
11 of 26
What is the ideal gas equation in terms of root mean square speed?
pV = 1/3Nm (Crms)2
12 of 26
If the volume of a container is fixed, what will happen to P?
The pressure will increase as; there will be more collisions in a given amount of time. Also, on average, a collision will result in a large change in momentum, and so exert a larger force.
13 of 26
If the pressure of a container is fixed, what happens to V?
The volume will increase to compensate for the temperature, this means there will be a longer time between molecule-wall collision. The rate of change of momentum will be reduced.
14 of 26
What is the root mean square speed?
The square root of the average of the squared speeds of the particles in a gas.
15 of 26
What are some of the assumptions of kinetic theory?
All molecules are identical, they move rapidly and randomly. Newonian mechanics apply, collisions are perfectly elastic, there are no forces between molecules except during collisions. The forces during collisions are instantaneous.
16 of 26
How does the energy of a molecule change?
As a result of collisions, energy will be transferred between molecules. Some molecules will gain speed in a collision and others will slow down. Between collisions, the molecules will travel at constant speed.
17 of 26
How is heat transferred?
Heat is always transferred from hotter substances to cooler substances. The higher the difference in temp between two substances, the faster the heat transfer between substances will happen.
18 of 26
What is the equation for kinetic energy of a gas molecule?
1/2m (Crms)2 = 3/2kT = 3RT/2NA
19 of 26
How can you find the total kinetic energy of gas molecules?
Once you have found the average kinetic energy of the molecules in a gas, you can find the total kinetic energy of the molecules as long as you know how many there are. Just multiply the average kinetic energy by the total number of molecules present
20 of 26
What is specific heat capacity?
The specific heat capacity (c) of a substance is the amount of energy needed to raise the temperature of 1kg of a substance by 1K
21 of 26
What is the equation for specific heat?
Q = mc T
22 of 26
What is specific latent heat?
The specific latent heat of fusion or vaporisation is the quantity of thermal energy required to change the state of 1kg of a substance.
23 of 26
What is the equation for specific latent heat?
Q = ml
24 of 26
What is the difference between fusion and vaporisation?
Fusion is a term used for the melting of a solid. The solid 'fuses' into a liquid as it melts. Vaporisation is a term used for when a liquid is turned to a gas. The molecules break away from each other to form bubbles of vapour in the liquid.
25 of 26
What is sublimation?
The process where solids vaporise directly when heated.
26 of 26

## Other cards in this set

### Card 2

#### Front

What is Boyle's Law?

#### Back

At a constant temperature, the pressure P and volume V of a gas are inversely proportional. pV = constant. p = 1/V

### Card 3

#### Front

What is Charles' Law?

### Card 4

#### Front

What is the 'pressure law'?

## Similar Physics resources:

See all Physics resources »See all Thermal physics resources »