Module 5 - 5.1.2 Solid, Liquid and Gas

Question 1

In the kinetic model of matter all matter is made up of

Answer 1

very small particles which are in constant motion

Question 2

Solids (2)
- movement of particles
- forces of attraction

Answer 2

• particles vibrate about their fixed positions
• particles held together by strong forces of attraction

Question 3

Liquids (3)
- movement of particles
- separation
- attractive forces

Answer 3

• particles cannot move much but can slide past one another
• much greater mean separation than solids
• attractive forces between them are weaker

Question 4

Gases (3)
- movement of particles
- forces of attraction
- compression

Answer 4

• particles are free to move around very quickly in random directions
• forces of attraction are very weak due to their high separation
• can be compressed easily

Question 5

Calculating Molecular Spacing

Answer 5

consider momentum (Newton’s 2nd law) and pressure of particle on each wall of the container (Newton’s 3rd law)

Question 6

A Change In Phase Requires (2)

Answer 6

• an input/removal of energy
• the extra energy inputted results in particles moving further apart until they have enough energy to overcome the forces of attraction

Question 7

During a Change in Phase (temperature and energy) (3)

Answer 7

• no change in temperature (no change in kinetic energy)
• produces a change in potential energy
• so internal energy changes

Question 8

Internal Energy (definition)

Answer 8

The sum of the randomly distributed kinetic and potential energies of all the atoms/molecules within a system

Question 9

Potential Energy (definition)

Answer 9

The potential energy of the system is stored in the bonds and intermolecular forces that exist between particles

Question 10

Kinetic and Potential Energies
- Solids
- Liquids
- Gases

Answer 10

• Solids and Liquids: both kinetic and potential
• Gases: only kinetic

Question 11

In any system of gas particles at a fixed temperature there will be (5)

Answer 11

• a distribution of kinetic energies among the molecules
• because there is a wide range of different translational speeds
• the peak of the curve shows the most probable speed
• low temp = higher peak at lower speed
• high temp = lower peak at higher speed

Question 12

Brownian Motion (definition)

Answer 12

The random movement of small visible particles suspended in a fluid due to collisions with much smaller, randomly moving atoms/molecules of the fluid

Question 13

Explanation of Brownian Motion (2)

Answer 13

• the smaller particles do not collide with the visible particles in the same direction or with the same speed
• so a net impulse is gained by the visible particles

Question 14

Brownian Motion: as the mass of the visible particles increases

Answer 14

their velocity will decrease (move around less)