Topic 2

Question 1

pure substance

Answer 1

only made up of a single element or compound

Question 2

you can yest for purity using

Answer 2

melting points
pure substances have specific sharp melting and boiling points

Question 3

distilation

Answer 3

seperate mixtures that contain liquids.

Question 4

simple distillation

Answer 4

seperating out a liquid from a solution

Question 5

simple distilation pratical

Answer 5

1.seawater in distalation flask
2.bottom of condenser on fo a cold tap with rubber tubing
3.heat flask
4.part of solution w lowest boiling point will evaporate
4.wtaer vapour passes thru condenser(back to liquid) n collected in beaker
5.js salt in flask

Question 6

fractional distalation

Answer 6

seperating mixture of liquids

Question 7

fractional distalation pratical

Answer 7

1.mixture in flas and attach a fractionalising column and condensed above the flask
2.heat flask-diff liquids w diff boiling poinys so they will evaporate at diff temps
3.liquid w lowest boiling point evaps first

Question 8

filterisation

Answer 8

seperate insoluble solid from liquid
-product=insoluble liquid
-purification
-filter paper in funnel and pour mixture in it, liwuid part runs theough leaving behind solid

Question 9

crystalisation

Answer 9

seperates soluble solid from solution
1.pour solution in evaporating dish+gently heat->some water evaporates n solution becomes more coneventrated
2.remove dish when crystal stary to form n cool
3.salt form crystals bc insiluble in cold
4.filter crystals and dry

Question 10

chromotography mobile phase

Answer 10

when the molecules can move
liquid or gas
solvent

Question 11

stationary ohase

Answer 11

molecules cabt moce
solid or thick liquid
paper

Question 12

time molecules spend in each phase delends om

Answer 12

how soluble they are in solvent
how attracted they are in stationary phase
higher solubility=more time in mobile phase->further ip paper

Question 13

Rf

Answer 13

distance travelled by solute over distance travelled by solvent

Question 14

surface water

Answer 14

lakes,rivers,reservoirs

Question 15

ground water

Answer 15

aquifers(rocks that trap water underground)

Question 16

waste water

Answer 16

water contaminated by human process

Question 17

filtration

Answer 17

wire mesh screens out large twigs,gravel,sand

Question 18

sedimentation

Answer 18

iron sulfate or aluminium sulfate added to water->makes fine particles clump together and settle at bottom

Question 19

chlorintation

Answer 19

chlorine gass bubbled thru to kill harmful bacteria n microbes

Question 20

distilling sea water

Answer 20

in dry countries
needs loads of energy->expensive
not used in uk

Question 21

deionisef water

Answer 21

used in chemical analysis
ions taken out eg calcium n copper
so dont intefer w reactions