Changes Of State

Question 1

Evaporation

Answer 1

In any liquid or gas, the average speed of the particles varies within the temperature. But at each temperature, some particles will be moving faster, others more slowly, than the average.
Some very fast particles on the surface of the liquid will have enough energy to break away and form a gas

Question 2

Sublimation

Answer 2

A small number of substances have the ability to change directly from solid to a gas, or vice versa, without involving any liquid on the way. Eg carbon dioxide

Question 3

Melting

Answer 3

In a solid, the energy makes the particles in it vibrate faster and faster.
Eventually, they vibrate fast enough that the forces of attraction between the particles are no longer strong enough to hold them together.
The solid melts to a liquid.
The temperature needed to melt the solid is its melting point

Question 4

Solid arrangement

Answer 4

Close together, regular layers in a lattice formation

Question 5

Movement In solids

Answer 5

Their particles vibrate on the spot

Question 6

Amount of energy in solids

Answer 6

Low

Question 7

Liquid arrangement

Answer 7

Close together but random

Question 8

Liquid movement

Answer 8

Move around each other. Touching at all times

Question 9

Liquid energy level

Answer 9

Higher than solid, less than gases

Question 10

Gases arrangement

Answer 10

Far apart, random

Question 11

Energy level gas

Answer 11

High (est)

Question 12

Movement of gases

Answer 12

Quickly in all directions

Question 13

Atom

Answer 13

Simplest particle from which all matter is made

Question 14

Molecule

Answer 14

A particle made from atoms bonded together

Question 15

Elements

Answer 15

A substance made up from only one kind of atom

Question 16

Compound

Answer 16

A substance made from atoms of different kinds chemically bonded together

Question 17

Mixture

Answer 17

More than one substance. Contains different types of particles that are not joined together

Question 18

Atomic number

Answer 18

How many protons there are in each atom

Question 19

Mass number

Answer 19

How many protons + neutrons there are in each atom

Question 20

Isotope

Answer 20

Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in reactive atomic made but not in chemical properties.
It doesn’t affect its charge as neutrons are neutrally charged

Question 21

Freezing

Answer 21

If the liquid is cooked again, the liquid particles will move around more and more slowly.
Eventually, they are moving slowly enough that the forces of attraction between them will hold them into a solid.
The liquid freezes .
The temperature needed for this is the freezing point