Colours

Question 1

Ag (s)

Answer 1

Silver. Learn

Question 2

AgBr (s)

Answer 2

Cream. Result of test for bromide ions (AgNO₃ + Br⁻) is a cream precipitate, which is silver bromide

Question 3

AgCl (s)

Answer 3

White. Result of test for chloride ions (AgNO₃ + Cl⁻) is a white precipitate, which is silver chloride

Question 4

AgI(s)

Answer 4

Yellow. Result of test for iodide ions (AgNO₃ + I⁻) is a yellow precipitate, which is silver iodide

Question 5

At(s)

Answer 5

Black. Black, probably, though nobody knows. The halogens get darker as we go down the group, and iodine is dark grey, so astatine is probably black.

Question 6

Au (s)

Answer 6

Gold. Learn

Question 7

BaSO₄ (s)

Answer 7

White. Result of test for sulfate ions (BaNO₃ + SO₄²⁻) which produces a white precipitate of barium sulfate

Question 8

Br₂ (aq)

Answer 8

Orange. Used in test to distinguish between an alkane (no result) and an alkene (goes colourless)

Question 9

Br₂ (l)

Answer 9

Red-brown. Bromine is one of only two elements which are liquid at room temperature. The other is mercury, which is very different from bromine.

Question 10

C (s)

Answer 10

It depends. Carbon comes in different forms (allotropes). Diamond is a colourless solid, graphite is a grey solid, and charcoal is black

Question 11

Ca(OH)₂ (aq)

Answer 11

Colourless. Limewater is calcium hydroxide

Question 12

Ca²⁺ (flame test)

Answer 12

Orange/red. Learn

Question 13

CaCO₃ (s)

Answer 13

White. Calcium carbonate. Marble/chalk/limestone. Is the white precipitate formed when carbon dioxide is bubbled through limewater

Question 14

Cl₂ (aq)

Answer 14

Green. Learn

Question 15

Cl₂ (g)

Answer 15

Green. Learn

Question 16

CO (g)

Answer 16

Colourless. Learn

Question 17

CO₂ (g)

Answer 17

Colourless. Learn

Question 18

Cr³⁺ (aq) (Triple Science Only)

Answer 18

Green. Oxidation of alcohol to carboxylic acid, using dichromate. The dichromate is reduced to Cr³⁺

Question 19

Cu (s)

Answer 19

Copper. Learn

Question 20

Cu(OH)₂ (s)

Answer 20

Blue. Copper (II) hydroxide. Is the result of test for Cu²⁺ ions (NaOH + Cu²⁺). Precipitate.

Question 21

Cu²⁺ (flame test)

Answer 21

Blue/green. Learn

Question 22

CuCO₃ (s)

Answer 22

Green. Learn. Copper carbonate

Question 23

CuO (s)

Answer 23

Black. Learn. Copper oxide is the black powder we can react with sulfuric acid to produce those lovely blue copper sulfate crystals

Question 24

CuSO₄ (aq)

Answer 24

Blue. Copper (II) sulfate solution. Crystallise this to make blue copper (II) sulfate crystals.

Question 25

CuSO₄ (s)

Answer 25

White. Anhydrous copper sulfate. Add this to a sample to see if the sample contains water. It it does, becomes hydrated copper sulfate (blue). This is the chemical test for presence of water.

Question 26

CuSO₄.5H₂O (s)

Answer 26

Blue. Hydrated copper (II) sulfate crystals

Question 27

Fe(OH)₂ (s)

Answer 27

Green. Iron (II) hydroxide. Is the result of test for Fe²⁺ ions (NaOH + Fe²⁺). Precipitate.

Question 28

Fe(OH)₃ (s)

Answer 28

Brown. Iron (III) hydroxide. Like rust. Is the result of test for Fe³⁺ ions (NaOH + Fe³⁺). Precipitate.

Question 29

HCl (aq)

Answer 29

Colourless. Most acids are colourless

Question 30

Hydrated iron (III) oxide

Answer 30

Brown. This is rust. Orange/brown.

Question 31

I₂ (aq)

Answer 31

Brown. Learn

Question 32

I₂ (g)

Answer 32

Purple. Learn

Question 33

I₂ (s)

Answer 33

Dark grey. Darker than the halogens above it in Periodic Table

Question 34

I₂ (s)

Answer 34

Dark grey. Darker than the halogens above it in Periodic Table

Question 35

K⁺ (flame test, or flame when K reacts with H₂O)

Answer 35

Lilac. Learn

Question 36

K₂Cr₂O₇ (aq) (Triple Science Only)

Answer 36

Orange. Potassium dichromate. Oxidation of alcohol to carboxylic acid, using dichromate. The dichromate is reduced to Cr³⁺

Question 37

Li⁺ (flame test)

Answer 37

Red. Learn

Question 38

Litmus (in acid)

Answer 38

Red. Learn

Question 39

Litmus (in alkali)

Answer 39

Blue. Learn

Question 40

Methyl orange (in acid)

Answer 40

Red. Learn

Question 41

Methyl orange (in alkali)

Answer 41

Yellow. Learn

Question 42

Methyl orange (when neutral)

Answer 42

Orange. Learn

Question 43

Mg (when burning)

Answer 43

Bright white light. Learn

Question 44

MgO (s)

Answer 44

White. White ash left behind when magnesium burns in oxygen

Question 45

Most gases (g)

Answer 45

Colourless. If you need to guess the colour of a gas, guess colourless

Question 46

Most solutions (aq)

Answer 46

Colourless. If you need to guess the colour of a solution, guess colourless

Question 47

N₂ (g)

Answer 47

Colourless. In the air around us (78%)

Question 48

Na⁺ (flame test)

Answer 48

Yellow. Learn

Question 49

O₂ (g)

Answer 49

Colourless. In the air around us (21%)

Question 50

Phenolphthalein (in acid)

Answer 50

Colourless. Learn

Question 51

Phenolphthalein (in alkali)

Answer 51

Pink. Learn

Question 52

S (s)

Answer 52

Yellow. Learn. Precipitate which forms in that kinetics experiment when acid reacts with thiosulfate

Question 53

Universal indicator (in acid)

Answer 53

Red. Learn

Question 54

Universal indicator (in alkali)

Answer 54

Purple. Learn

Question 55

F₂ (g)

Answer 55

Yellow. Fluorine is the lightest coloured of all the Halogens. Learn.