Particles and their behaviour End of year test

Question 1

What are the three states of matter?

Answer 1

Solid, liquid, gas.

Question 2

Define sublimation.

Answer 2

Solid changes directly to gas.

Question 3

Name a substance that sublimes.

Answer 3

Dry ice or iodine.

Question 4

What happens to particles during melting?

Answer 4

Gain energy, move apart.

Question 5

Difference between evaporation and boiling?

Answer 5

Evap: surface, any temp. Boil: all through, fixed temp.

Question 6

Define condensation.

Answer 6

Gas to liquid.

Question 7

What is the melting point?

Answer 7

Temp where solid becomes liquid.

Question 8

Why do pure substances have a flat melting point line?

Answer 8

Same particles, energy breaks bonds.

Question 9

What state can’t flow or be compressed?

Answer 9

Solid.

Question 10

What happens to particles during freezing?

Answer 10

Lose energy, become fixed.

Question 11

How to identify a mixture from a heating graph?

Answer 11

No flat line during melting/boiling.

Question 12

What is the boiling point of water?

Answer 12

100°C.

Question 13

What happens to temp during boiling?

Answer 13

Stays constant.

Question 14

Why does a pure substance have a sharp boiling point?

Answer 14

All particles need same energy.

Question 15

What is a material’s property?

Answer 15

Describes appearance/behavior.

Question 16

Name a property of gases.

Answer 16

Can be compressed.

Question 17

What happens to particles during condensation?

Answer 17

Lose energy, move closer.

Question 18

Why do solids have fixed shapes?

Answer 18

Particles tightly packed.

Question 19

What is the state of matter of steam?

Answer 19

Gas.

Question 20

What is a pure substance?

Answer 20

Same properties throughout.

Question 21

Define diffusion.

Answer 21

Particles move high to low conc.

Question 22

Why is diffusion faster in gases?

Answer 22

Particles move more freely.

Question 23

How does temperature affect diffusion?

Answer 23

Higher temp = faster diffusion.

Question 24

Why can’t diffusion happen in solids?

Answer 24

Particles fixed in place.

Question 25

Effect of particle size on diffusion?

Answer 25

Larger = slower diffusion.

Question 26

Example of diffusion in liquids?

Answer 26

Food colouring in water.

Question 27

Why does a smell spread faster in warm air?

Answer 27

Particles move faster.

Question 28

What if particle size decreases in diffusion?

Answer 28

Diffusion speeds up.

Question 29

Name a fast-diffusing gas.

Answer 29

Oxygen or helium.

Question 30

Why doesn't diffusion need energy?

Answer 30

It's passive, random movement.

Question 31

What causes gas pressure?

Answer 31

Particles hit container walls.

Question 32

How does temp affect gas pressure?

Answer 32

Higher temp = higher pressure.

Question 33

What if container size increases?

Answer 33

Pressure decreases.

Question 34

Why does a balloon expand when heated?

Answer 34

Particles move faster, more pressure.

Question 35

What if more gas particles are added?

Answer 35

Pressure increases.

Question 36

Why do gas particles hit container walls?

Answer 36

Move randomly.

Question 37

Unit of pressure?

Answer 37

Pascals (Pa).

Question 38

How does particle size affect gas pressure?

Answer 38

Smaller = faster, more pressure.

Question 39

Why does a gas cylinder feel cold when gas escapes?

Answer 39

Gas expands, loses energy.

Question 40

What if a container is compressed?

Answer 40

Pressure increases.

Question 41

Define a mixture.

Answer 41

Different particles, non-uniform.

Question 42

What is a particle?

Answer 42

Tiny building block of matter.

Question 43

Property of liquids?

Answer 43

Can flow, not compressed.

Question 44

Gas to solid state change?

Answer 44

Deposition.

Question 45

Why do gases fill containers?

Answer 45

Particles move freely.

Question 46

What happens to energy during evaporation?

Answer 46

Particles gain energy.

Question 47

Opposite of sublimation?

Answer 47

Deposition.

Question 48

Why do solids have fixed volumes?

Answer 48

Particles tightly packed.

Question 49

Liquid to gas state change?

Answer 49

Boiling or evaporation.

Question 50

Why are gases less dense than solids?

Answer 50

Particles far apart.