States of Matter 1.1-1.7C

Question 1

Describe the arrangement, movement and energy of particles in solids

Answer 1

• Strong forces of attraction between particles
• Held close together in fixed positions in a regular lattice arrangement
• Don’t move from their positions so solids keep a definite shape and volume
• Particles vibrate about their positions
• When hotter = more vibration (expansion slightly)

Question 2

Describe the arrangement, movement and energy of particles in liquids

Answer 2

• Weak force of attraction between the particles.
• Randomly arranged and free to move past each other, but tend to stick closely together
• Definite volume but not a definite shape, flow to fill bottom of a container
• Particles are constantly moving with random motion
• Hotter the liquid gets, the faster they move = liquids expand slightly when heated

Question 3

Describe the arrangement, movement and energy of particles in gases

Answer 3

• Force of attraction between particles is very weak, free to move and particles are far apart
• Particles travel in straight lines
• Don’t keep a definite shape or volume and will always fill any container
• Particles move constantly with random motion
• Hotter the gas gets = faster movement -> expand or pressure increase

Question 4

Describe subliming

Answer 4

Solid to gas

Heat supplied

Question 5

Describe melting

Answer 5

Solid to liquid
Heated and the solid’s particles gain more energy. Particles vibrate more which weakens the forces that hold the solid together - expands
At a certain temperature, the particles have enough energy to break free from their positions

Question 6

Describe

Question 7

Describe evaporating

Answer 7

Liquid to gas
Liquid is heated and gains energy which makes the particles move faster, which weakens and breaks the bonds holding the liquid together
At a certain temperature, the particles have enough energy to break their bonds

Question 8

Describe freezing

Answer 8

Opposite to melting
Liquid to solid
Heat given out

Question 9

Describe condensing

Answer 9

Opposite of evaporating
Gas to liquid
Heat given out

Question 10

Define diffusion (chemistry def)

Answer 10

The random movement of particles from an area of high concentration to an area of low concentration
Movement of particles through a liquid or gas

Question 11

Describe the diffusion experiment using potassium manganate (VII) and water

Answer 11

Take a beaker of water and place some potassium manganate (VII) at the bottom, the purple colour slowly spreads to fill the beaker
The particles are diffusing out
Random motion of particles in a liquid causes the purple colour to eventually be evenly spread out throughout the water

Question 12

What would happen if you added more water to the potassium manganate solution?

Answer 12

Dilution

The potassium manganate (VII) particles would spread even further apart and the solution would be less purple

Question 13

Describe the ammonia and hydrogen chloride diffusion experiment

Answer 13

Set up: glass tube - at one end a cotton wool soaked in aqueous ammonia (NH3) and the other a cotton wool soaked in hydrochloric acid (HCl)

1) The NH3 gives off ammonia gas and HCl gives off hydrogen chloride gas
2) NH3 gas diffuses from one end of the tube and the HCl gas diffuses from the other - they react to form a white ring of ammonium chloride
3) Forms nearest the end of the HCl because the NH3 particles are smaller and lighter so diffuse through the air more quickly

Question 14

Describe the bromine gas and air diffusion experiment

Answer 14

1) Fill half a gas jar full of bromine gas (brown, strong smelling) , the other half full of air - separate with a glass plate
2) Remove glass plate, the bromine gas slowly diffuses through the air
3) The random motion of the particles means that the bromine will eventually diffuse right through the air

Question 15

Describe dissolving

Answer 15

A solid (the solute) is added to a liquid (the solvent) and the bonds holding the solute molecules together sometimes break and the molecules mix with the liquid molecules

Question 16

Define solution

Answer 16

A mixture of a solute and a solvent that does not separate out

Question 17

Define solute

Answer 17

The substance being dissolved

Question 18

Define solvent

Answer 18

The liquid the solute is being dissolved into

Question 19

Define saturated solution

Answer 19

A solution where the maximum amount of solute has been dissolved, so no more solute will dissolve in the solution

Question 20

Define solubility and what units does it use?

Answer 20

The ability of a substance to dissolve in a solvent
Gram of solute/100 grams of the solvent
The solubility of most solid substances increases as you increase the temperature

Question 21

How do you plot and interpret solubility graphs

Answer 21

Solubility on y axis
Temperature along x axis
Can find the solubility of a substance at a specific temperature by drawing a line from the temperature on the x axis up to the curve then read across on the y axis

Question 22

What is the equation for solubility

Answer 22

solubility (g per 100g of solvent) = mass of solid(g)/mass of water removed (g) x100

Question 23

Describe an experiment to investigate the solubility of a solid in water at a specific temperature

Answer 23

1) Make a saturated solution (sinks to the bottom) by adding an excess of ammonium chloride to 10cm3 of water in a boiling tube
2) Stir the solution and place the boiling tube in a water bath set to 25C
3) After 5 minutes, check that all of the excess solid has sunk to the bottom of the tube and use a thermometer to check that the solution has reached 25C
4) Weight an empty evaporating basin. Pour some of the solution into the basin, making sure not to pour in any of the undissolved solid
5) Re-weight the basin then gently heat it using a Bunsen burner to remove all the water
6) Once all the water has evaporated and left with pure ammonium chloride. Reweigh the evaporating basin and its contents
7) Repeat steps 1-6 twice more, but with the water bath at different temperature
8) You can use the different masses to work out the solubility at each temperature

Question 24

Why does it take time for us to be able to smell a substance that diffuses?

Answer 24

The molecules move randomly and bounce off air particles as they move around the lab

Question 25

Why is diffusion in liquids slower than in gases?

Answer 25

The particles in a liquid are closer together so diffusion is slower