Human Organ Systems

Question 1

Define matter and state the particle theory. (2)

Answer 1

Matter is anything which occupies space and has a mass. (1)

The particle theory states that particles in a substance stays then same, in any of the three states, and the energy and arrangement of particles is what changes. (1)

Question 2

Distinguish between the three main states of matter, solid, liquid and gas in terms of their particle arrangement. Give examples of each. (4)

Answer 2

Solids - particles are held very tightly together (1)
Liquids - particles are close together but they can move (1)
Gases - particles are spread far apart from each other (1)

Ice - Solid: Water - Liquid: Steam - Gas (1)

Question 3

What is a physical change? (1)

Answer 3

A physical change is when substance changes without becoming a new chemical. It can be reversed easily. (1)

Question 4

Define melting, boiling, evaporation, freezing and sublimation. (5)

Answer 4

Melting is when a solid turns into a liquid. (1)

Boiling is when bubbles of gas form throughout the liquid. (1)

Evaporation is when a liquid turns into a gas. (1)

Freezing is when a liquid turns into a solid. (1)

Sublimation is when a solid turns straight into a gas. (1)

Question 5

Define boiling and melting point. (2)

Answer 5

A boiling point is the temperature at which a liquid changes into a gas. (1)

A melting point is the temperature at which a solid changes into a liquid. (1)

Question 6

Is energy (usually thermal energy)
required for a change of state to occur? (1)

Answer 6

Yes. (1)

Question 7

Define diffusion. (1)

Answer 7

Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration. (1)

Question 8

Describe gas pressure in terms of volume and
temperature. (1)

Answer 8

Gas pressure is the name given to the force exerted by gas particles colliding with the wall of their container. (1)