Topic 1 - Particles & Mixtures

Question 1

Features of Solids

Answer 1

• Strong forces of attraction
• Held in fixed lattice structure
• Keeps definite shape & volume
• vibrate in fixed position

Question 2

Features of Liquids

Answer 2

• Weak forces of attraction
• Free to move
• Compact
• Definite volume, shape can change

Question 3

Features of Gases

Answer 3

• Very weak forces of attraction
• No definite shape or volume
• constantly moving randomly
• free to move

Question 4

Process of Melting

Answer 4

Increased temperature
solid -> liquid
particles gain kinetic energy and break free of lattice

Question 5

Process of Boiling

Answer 5

Increased temperature
liquid -> gas
particles gain kinetic energy and break bonds completely

Question 6

Process of Condensing

Answer 6

Decreased temperature
gas -> liquid
particles dont have enough energy to overcome forces and become liquid

Question 7

Process of Freezing

Answer 7

Decreased temperature
liquid -> solid
particles dont have enough energy to overcome forces and become solid

Question 8

Diffusion

Answer 8

net movement of particles from an area of high concentration to an area of low concentration

Question 9

Three diffusion practicals

Answer 9

1. Bromine gas
   - test tubes separated by glass plate, glass plate is removed, gas distributes across
2. Potassium Manganate
   - lump will sink to bottom, colour spreads out as particles diffuse, eventually will evenly distribute
3. HCl & NH3 cotton wools
   - soak two cotton wools in HCl and NH3, see where white ring forms, ring is closer to HCl as particles are smaller

Question 10

Solute

Answer 10

Substance that dissolves in the solvent

Question 11

Solvent

Answer 11

Liquid the solute dissolves in

Question 12

Solution

Answer 12

Mixture of solute and solvent

Question 13

Saturated Solution

Answer 13

Solution in which maximum amount of solute has dissolved

Question 14

Solubility

Answer 14

Maximum amount of substance that will dissolve in a given amount of solvent at a certain temperature

measured in g/100g

as temperature increases, solubility increases

Question 15

Charge of Proton

Answer 15

+1

Question 16

Charge of Electron

Answer 16

-1

Question 17

Mass of Protons & Neutrons

Answer 17

1

Question 18

Charge of Neutron

Answer 18

Neutral

Question 19

Relative atomic mass equation

Answer 19

Relative atomic mass = (abundance of isotope 1 x mass of isotope 1) + (abundance of isotope 2 x mass of isotope 2) / 100

Question 20

Molecule

Answer 20

Held together by 2 or more atoms by chemical bonds

E.g. O2, N2, Cl2

Question 21

Compound

Answer 21

Made from two or more elements by chemical bonds

E.g. Hydrogen Sulfate (H2SO4)

Question 22

Mixture

Answer 22

Made from two or more elements NOT chemically bonded

E.g. seawater

Question 23

Filtration

Answer 23

Insoluble solids from liquids

• ## filter paper has small holes large enough to allow water to pass, but not solids

Question 24

Evaporation

Answer 24

Soluble solids from liquids (solution)

• place solution in evaporating dish/crucible
• slowly heat with bunsen burner
• solvent evaporates
• crystals form as it is concentrated

Question 25

Crystallisation

Answer 25

- place solution in evaporating dish - once crystals form, leave to cool - filter out crystals from solution using filter paper - blot crystals dry

Question 26

Paper Chromatography

Answer 26

used to separate substances in a mixture (e.g. dyes in ink) 1. take filter paper, draw baseline with a pencil 2. add ink to baseline 3. fill beaker with solvent 4. dip bottom of paper in solvent without submerging ink 5. Place lid to stop solvent from evaporating 6. watch as dyes travel up paper | * ink components = MOBILE PHASE * paper = STATIONARY PHASE

Question 27

Rf Values

Answer 27

distance travelled by substance / distance travelled by solvent

Question 28

Simple Distillation

Answer 28

- liquid from solution - solution heated using bunsen burner - liquid in mixture evaporates into gas - gas is cooled by water jacket and condenses into liquid, flowing into beaker

Question 29

Fractional Distillation

Answer 29

liquids with different boiling points from solution - same as simple, except it passes through fractionating column which increases surface area