Kinetic Theory And Kinetic Theory Of Gases

Question 1

Kinetic theory of matter

Answer 1

1. All matter is made up of particles
2. Move constantly (have kinetic energy)
3. Empty spaces between particles (possess potential energy)
4. Forces of attraction exist if they’re relatively close but forces of repulsion exist if they’re too close
5. Particles collide with one another
6. Temperature is the measure of the average kinetic energy of the particles
7. Phase changes take place when energy is absorbed or released

Question 2

Kinetic molecular theory of gases

Answer 2

1. Gases are very far apart
2. Gas molecules have a great amount on energy
3. So far apart that attraction force between the molecules are weak
4. Exert pressure when colliding with objects or side of container
5. Number of collision per second cause the force and pressure against the sides of the container

Question 3

Kinetic theory (solids, liquids, gases)

Answer 3

Solid: close together, Ek decreases
Liquid: further apart, ek increases, moves faster
Gas: furthest apart, Ek highest, move fastest

Question 4

Temperature

Answer 4

A measure of the average kinetic energy of the gas particles

Question 5

Pressure

Answer 5

Can be defined as the force per unit area

Question 6

Two factors that affect the pressure

Answer 6

1. The average velocity of the gas molecules

2. The mass of the gas molecules at the time they collide with the walls of the container

Question 7

Physical quantities of a gas: pressure, volume, temperature, quantity gas

Answer 7

Pressure: is usually measured in pascal (Pa) or kilo pascal (kPa). Standard pressure is 101,2 kPa
Volume: the amount of space that a gas occupies at a certain temperature and pressure. Volume of a gas is usually expresse as cubic centimeters (cm3), cubic decimeters (dm3) or cubic meter (m3)
Temperature: T(K) = (°C) + 273
Quantity gas: is expressed in mol (n)

Question 8

Ideal gas

Answer 8

An ideal gas is a theoretical gas that obeys all the ideal gas laws under all circumstances of pressure and temperature

Question 9

Properties of an ideal gas

Answer 9

• gas particles are identical
• gas molecule does not occupy volume
• no forces of attraction or repulsion
• all collisions are elastic (no energy is lost during collision. Energy can be transferred
• temperature is a measure of the average kinetic energy of the gas molecules
• the pressure exerted is due to the collision of the gas molecules

Question 10

When will real gases show ideal behaviour?

Answer 10

1. High temperatures
   - gas molecule has higher kinetic energy
   - gas molecules move faster and further apart so that the attractive forces decrease
   - it increases the volume
2. Low pressure:
   - gas molecules move far away
   - forces of attraction are negligible
   - gas molecules do not contribute to the volume of the gas

Question 11

Real gases nearest to that of an ideal gas

Answer 11

He and H2. Are very small and non-polar with weak Van der Waals forces between the gas particles. Because particles are so small, the volume of the particles will only contribute to the total gas volume at extremely high pressure

Question 12

Real gases vs ideal gases

Answer 12

Real gases deviate from ideal gases at low temperature and high pressure
Real gases obey the ideal gas law at low pressure and high temperature

Question 13

When will real gases deviate from ideal gases

Answer 13

1. Low temperature
   - average kinetic energy is lower
   - force of attraction increase
   - volume is larger than what the ideal gas law predict
   - gas liquifies

High pressure:

• gas molecules move closer together
• intermolecular forces are greater
• volume of gas is greater than what ideal gas law predicts
• gas molecules contribute to volume

Question 14

Ideal gas equation

Answer 14

pV = nRT