C8 - Chemical Analysis

Question 1

What is a cation?

Answer 1

A positive ion

Question 2

What is an anion?

Answer 2

A negative ion

Question 3

What colour flame will copper ions produce?

Answer 3

Green

Question 4

What colour flame will sodium ions produce?

Answer 4

Yellow

Question 5

What colour flame will calcium ions produce?

Answer 5

Brick red

Question 6

What colour flame will lithium ions produce?

Answer 6

Crimson

Question 7

What colour flame will potassium ions produce?

Answer 7

Lilac

Question 8

What reagent do we use to test for metal ions?

Answer 8

Sodium hydroxide (NaOH)

Question 9

What colour precipitate will copper ions produce?

Answer 9

Blue

Question 10

What colour precipitate will magnesium ions produce?

Answer 10

White

Question 11

What colour precipitate will calcium ions produce?

Answer 11

White

Question 12

What colour precipitate will aluminium ions produce?

Answer 12

White

Question 13

What colour precipitate will Fe2+ ions produce?

Answer 13

Green

Question 14

What colour precipitate will Fe3+ ions produce?

Answer 14

Brown

Question 15

How can we tell the difference between the white precipitate of magnesium (or calcium) and the white precipitate of aluminium?

Answer 15

Al3+ ions will redissolve in excess NaOH, magnesium (and calcium) ions will not

Question 16

What reagent do we use to test for sulfate ions?

Answer 16

Acidified Barium Chloride

Question 17

What is the formula of a sulfate ion?

Answer 17

SO4^2-

Question 18

What colour precipitate will sulfate ions produce with acidified barium chloride?

Answer 18

White

Question 19

What reagent do we use to test for carbonates

Answer 19

Acid

Question 20

What is the positive result for a carbonate test?

Answer 20

Bubbles of CO2 produces

Question 21

What happens to lime water if carbon dioxide is present?

Answer 21

It turns cloudy

Question 22

What is the test for chlorine?

Answer 22

Damp blue litmus paper

Question 23

What it the positive result of the chlorine test?

Answer 23

Bleaches damp blue litmus white

Question 24

How do you calculate Rf value in chromatography?

Answer 24

Distance moved by dot
————————————-
distance moved by solvent

Question 25

Why must we draw our start line with a pencil in chromatography?

Answer 25

So it doesn’t spread up the page

Question 26

What elements make up the halogens?

Answer 26

Fluorine, Chlorine, Bromine, Iodine

Question 27

What reagent do we use to test for halide ions?

Answer 27

Acidified silver nitrate

Question 28

What colour precipitate do Cl- ions make with acidified silver nitrate?

Answer 28

White

Question 29

What colour precipitate do Br- ions make with acidified silver nitrate?

Answer 29

Cream

Question 30

What colour precipitate do I- ions make with acidified silver nitrate?

Answer 30

Yellow

Question 31

Pure substances have very specific…

Answer 31

Melting/Boiling points

Question 32

What is a formulation?

Answer 32

Mixtures of certain quantities of substances designed to fulfil a specific purpose

Question 33

4 examples of formulations

Answer 33

Paints
Alloys
Fertilisers
Fuels

Question 34

What is chromatography?

Answer 34

The separating of a mixture to identify its constituent substances eg pigments in ink, drugs in urine sample

Question 35

Advantages of flame emission spectroscopy

Answer 35

Accurate
Sensitive
Rapid

Question 36

What is flame emission spectroscopy

Answer 36

Analysing the wavelengths of light emitted from a flame to identify ions accurately

Question 37

Test for oxygen

Answer 37

Relight a glowing splint

Question 38

Test for hydrogen

Answer 38

Lit splint, squeaky pop

Question 39

Test carbon dioxide

Answer 39

Causes limewater to turn cloudy when bubbled through it