Chemical Analysis

Question 1

DEFINE a pure substance

Answer 1

Contains 1 type of substance

Question 2

Define a formulation

Answer 2

A mixture designed to produce a useful product e.g paint , fertilisers.

Question 3

DESCRIBE how you test for hydrogen gas

Answer 3

Place a lit splint in the gas

Question 4

Give the positive result for hydrogen gas

Answer 4

squeaky “POP”

Question 5

describe how you test for oxygen gas

Answer 5

place a glowing splint in the gas

Question 6

give the positive result for oxygen gas

Answer 6

glowing splint relights

Question 7

Describe how you test for carbon dioxide gas

Answer 7

Bubble the gas through lime water

Question 8

Give the positive result for carbon dioxide gas

Answer 8

limewater turns cloudy

Question 9

Describe how you would test for chlorine gas

Answer 9

using blue litmus paper

Question 10

Give the positive result for chlorine gas

Answer 10

blue litmus paper turns white

Question 11

describe the process of chromatography

Answer 11

Separation technique used to separate soluble substances

Question 12

identify 3 rules you must follow when setting up a chromatography experiment

Answer 12

1 start line drawn in pencil
2 Water level below start line
3 Spots spaced 1cm apart

Question 13

Define rf

Answer 13

retention factor

Question 14

explain what the RF value shows

Answer 14

measure of solubility

Question 15

describe how you calculate an rf value for a substance

Answer 15

distance moved by substance / distance moved by solvent

Question 16

what do high rf values indicate

Answer 16

high solubilities

Question 17

describe what small rf values indicate

Answer 17

low solubilities