States of Matter

Question 1

Solids

Answer 1

• strong forces of attraction between particles, which holds them close together in fixed positions to form a regular lattice arrangement
• particles DONT MOVE but vibrate about their positions… the hotter the solids become the more they vibrate , causing them to expand slightly when heated

Question 2

liquids

Answer 2

• weak force of attractions between the particles.
• they’re randomly arranged
• and free to move but usually stick close together
• definite volume but not a definite shape
• particles constantly moving randomly. the hotter the liquids get the faster they move = expand when heated

Question 3

gases

Answer 3

• forces of attraction between particles is very weak - particles travel in straight lines
• don’t keep a definite shape or volume
• move constantly with random motion
• hotter the gas faster it moves

Question 4

solvent

Answer 4

the LIQUID it’s dissolving into

Question 5

solute

Answer 5

the substance being dissolved

Question 6

solution

Answer 6

a mixture of a solute and solvent

Question 7

saturated solution

Answer 7

a solution where the maximum amount of solute has been dissolved so no more solute will dissolve

Question 8

solubility

Answer 8

a measure of how much solute will dissolve in a solvent. often measured in grams of solvent per 100g of solvent

Question 9

solubility of a solid practical

Answer 9

1. saturated solution
2. stir and place in water bath at 25°c
3. after 5 mins check all excess has fallen to bottom and check temp has reached 25
4. weigh an empty evaporating basin. pour some of the solution into basin
5. reweigh basin and contents and gently heat using a bunsen burner to remove all water
6. once all water has evaporated you’re left with pure ammonium chloride
7. reweigh evaporating basin and contents
8. repeat twice more at different temps
9. use masses to work out solubility

Question 10

solubility equation

Answer 10

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

Question 11

atom

Answer 11

made up of protons neutrons and electrons

Question 12

atomic number

Answer 12

how many PROTONS there are

Question 13

mass number

Answer 13

number of protons and neutrons

Question 14

molecules

Answer 14

groups of atoms

Question 15

compounds

Answer 15

a substance made of 2 or more different elements that are chemically bonded together.

difficult to separate, properties completely different to original elements.

Question 16

mixtures

Answer 16

• easy to separate
• no chemical bonds.
• not a pure substance (boil or melt over a ranges of temps )

Question 17

pure substance

Answer 17

= fixed melting and boiling point

Question 18

simple distillation

Answer 18

separate a liquid from a solution. eg. pure water from seawater.

1. solution is heated, part with lowest boiling point evaporates
2. vapour is cooled and condenses and is collected
3. rest of solution left behind.

Question 19

fractional distillation

Answer 19

separate a mixture of liquids

1. put mixture in flask with fractionating column on top, heat it
2. different liquids = different boiling points = evaporate at different temps
3. liquid with lowest boiling point evaporates first. reaches top of column and is collected. raise temp and next is collected

Question 20

filtration

Answer 20

separate an insoluble solid from a liquid

Question 21

crystallisation

Answer 21

separate a soluble solid from a solution

1. pour into evaporating dish. gently heat. some water evaporates and solution more concentrated
2. remove from heat and leave to cool
3. leave in a warm place and crystals will form.

Question 22

paper chromatography

Answer 22

1. draw a pencil line near bottom of a sheet of filter paper
2. add spots of different inks to the line at regular intervals
3. place in a beaker of solvent (water) with level of solvent below the baseline
4. place a lid to stop the solvent evaporating
5. the solvent seeps up the paper carrying the inks with it
6. each different dye in the inks will move up the paper at a different rate and form a spot in a different place
7. when solvent nearly reached the top take paper out of beaker and leave to dry = chromatogram

Question 23

how to calculate Rf value

Answer 23

Rf = distance travelled by solute / distance travelled by solvent