Changes Of State

Question 1

What happens when a solid or liquid is heated

Answer 1

The particles gain energy, vibrate faster until they have enough energy to overcome the forces of attraction between the particles and molecules to break free.

Question 2

What happens when a gas or liquid is cooled

Answer 2

The particles loose energy and start to move and vibrate slower until they can’t overcome the forces of attraction and move closer together (liquid) or get stuck in a fixed position (solid)

Question 3

What is equal to what at the boiling point

Answer 3

Atmospheric pressure=vapor pressure

Question 4

Where does boiling occur

Answer 4

Throughout the liquid but only at boiling point.

Question 5

Where does evaporation take place and what is it?

Answer 5

It takes place at the surface of a liquid and it is the removal of energy

Question 6

When does evaporation take place

Answer 6

When the particles near the surface have enough energy to overcome the forces holding the liquid molecules together and they move into the space above the liquid.

Question 7

When does condensation take place

Answer 7

When a gas is cooled to its boiling point and below

Question 8

What is the boiling and melting/freezing point of water

Answer 8

100
0
MELTING + FREEZING POINT=THE SAME

Question 9

Iron

Answer 9

2860

1538

Question 10

Gold

Answer 10

2856

1063

Question 11

Mercury

Answer 11

357

-39

Question 12

Platinum

Answer 12

3825

1768

Question 13

Oxygen

Answer 13

• 183

- 225

Question 14

Hydrogen

Answer 14

• 253

- 260

Question 15

What is sublimation

Answer 15

Solid to gas without going through the liquid stage eg. Dry ice sublimes+solid iodine

Question 16

What is the change of state from gas to solid and eg.

Answer 16

Deposition

Frost

Question 17

True false some substances have the same melting point/boiling point

Answer 17

False

All are unique

Question 18

How can a scientist find out a substances purity

Answer 18

By finding its melting/freezing/boiling points
They can compare it to known points
If it melts over a range=impure
Or at different temp.

Question 19

What is the Brownian motion

Answer 19

The random movement of particles suspended in a fluid (liquid or gas) from colliding with fast moving molecules/atoms in gas/liquid.

Question 20

What is the Brownian motion named after and how did he discover it

Answer 20

Robert brown

By looking at pollen grains (in 1827) randomly moving in mater. He could not explain

Question 21

How and who explained the Brownian motion

Answer 21

Albert Einstein ion 1905, the grains were being moved by individual water molecules.

Question 22

What is diffusion

Answer 22

The movement and mixing of particles from areas of higher concentration to lower concentration.

Question 23

What is an equilibrium

Answer 23

The state in which opposing forces are balanced.

Question 24

What is volatile

Answer 24

Easily evaporated, unpredictable, changes rapidly

Question 25

1 degree Celsius = to what kelvin

Answer 25

273,15

Question 26

Si unit for density

Answer 26

Kg/m3

Question 27

What is active transport

Answer 27

Movement of molecules/ cells from areas of lower concentration to higher.

Question 28

What is osmosis

Answer 28

Osmosis is the scientific process of transferring fluid between molecules.
High to low