chap3: separation techniques

Question 1

what is mixture?

Answer 1

mixture is made up of 2 or more substances that are not chemically combined

Question 2

filtration

Answer 2

separate insoluble solids from a liquid
filtrate (liquid) residue (solid)

Question 3

evaporation to dryness

Answer 3

obtain a soluble solid from a solution by heating the solution until all water has boiled off (salt)

Question 4

crystallisation

Answer 4

used to obtain pure solid crystals (sugar)

Question 5

simple distillation

Answer 5

use to separate pure solvent from a solution

water enter at the bottom and leaves at the top

bulb of thermometer should be placed beside the opening of condenser, should not dip in solution

Question 6

fractional distillation

Answer 6

separate mixture of miscible liquids with different boiling points

Question 7

what is boiling chip use for?

Answer 7

to ensure smooth boiling

Question 8

chromatography

Answer 8

separate small quantities of mixtures

used to determine if a sample is pure or identify substances such as drugs or poisons

if pure -> show 1 dot
most soluble -> the furthest

Question 9

test for purity

Answer 9

fixed melting and boiling points

Question 10

why are food colouring R and B safe to use in food?

Answer 10

food colouring R and B has the same dyes and ER and EB respectively

Question 11

why is the line drawn in pencil instead of ink?

Answer 11

ink will dissolve and get separated