Introduction to the particulate nature of matter - changes of state

Question 1

What are the properties of a solid?

Answer 1

• fixed volume and shape
• high density
• atoms vibrate, do not move
• strong attractive forces between particles
• particles have a fixed and regular pattern

Question 2

What are the properties of a liquid?

Answer 2

• fixed volume, no fixed shape
• cannot be compressed
• weaker attractive forces between particles than in solids
• particles can move and slide past each other

Question 3

What are the properties of a gas?

Answer 3

• no fixed volume or shape
• can be compressed
• negligible attractive forces between particles
• particles move randomly and quickly
• low density

Question 4

Change of state definition

Answer 4

Reversible, physical changes in a substance’s state of matter that occur as they absorb or release energy. Does not change chemical properties or makeup.

Question 5

What are the 6 changes in state?

Answer 5

melting: solid → liquid
freezing: liquid → solid
vaporising: liquid → gas
condensing: gas → liquid
sublimation: solid → gas
deposition: gas → solid

Question 6

Draw / describe a change in state graph

Answer 6

°C against increasing energy.
Increasing temperature for solid, liquid and gas
Temperature stable in transitions

Question 7

What are the endothermic changes of state?

Answer 7

Melting, boiling and sublimation.
More condensed → less
Energy is absorbed.

Question 8

What are the exothermic changes of state?

Answer 8

Deposition, condensing and freezing.
Less condensed state → more
Energy released, stronger intermolecular forces.