C4 Predicting and Identifying Reactions and Products

Question 1

What happens when alkali metals react with air?

Answer 1

They can tarnish and go dull, because they have become covered in a layer of metal oxide.

Question 2

What happens when alkali metals react with chlorine?

Answer 2

A vigorous chemical reaction takes place and a white crystalline salt is formed.

Question 3

What happens when alkali metals react with water?

Answer 3

A quick and vigorous chemical reaction takes place, giving off hydrogen gas and forming a metal hydroxide, which dissolves in water to form an aqueous alkaline solution.

Question 4

Describe the Halogen colours

Answer 4

Fluorine, very reactive, poisonous yellow gas at room temp.

Chlorine, fairly reactive, poisonous dense green gas at r .t

Bromine, dense poisonous orange volatile liquid at r.t - forms an orange gas

Iodine is dark grey crstalline solid at room temp or a purple vapour.

(Goes from gases to solid - shows a trend in melt and boiling points.)

Question 5

What happens in displacement reactions of halogens?

Answer 5

If an aqueous halide solution reacts with a more reactive halogen than is present (one further up the group), the more reactive halogen will displace the other, to form a different halide.

Question 6

What happens when halogens and alkali metals react?

Answer 6

A halide- an ionic compound of a halogen and an alkali metal, e.g. lithium chloride, sodium bromide- is produced in an exothermic reaction. These compounds conduct electricity when molten or dissolved in water. The reaction becomes less vigorous as you go down the group of .metals.

Question 7

Why do molten salts conduct electricity?

Answer 7

Salts are ionic compounds, which means they have a regular lattice of positively and negatively charged ions. When they are molten or dissolved in water, they can conduct electricity because the ions are free to move around and carry electric charges They cannot conduct electricity in a solid form as there are strong forces of attraction between oppositely charged ionic bonds meaning electrons cannot move.

Question 8

All nitrates

Answer 8

Are soluble

Question 9

All potassium salts

Answer 9

Are soluble

Question 10

All sodium salts

Answer 10

Are soluble

Question 11

All silver salts

Answer 11

Are insoluble

Question 12

Barium sulfate

Answer 12

Is insoluble

Question 13

Calcium carbonate

Answer 13

Is insoluble

Question 14

Hydroxides of non-Group 1 metals

Answer 14

Are insoluble

Question 15

Copper hydroxide precipitate

Answer 15

Light blue

Question 16

Iron (II) hydroxide precipitate

Answer 16

Green

Question 17

Iron (III) hydroxide precipitate

Answer 17

Red - brown

Question 18

Calcium hydroxide precipitate

Answer 18

White (insoluble in excess NaOH)

Question 19

Zinc hydroxide precipitate

Answer 19

White (soluble in excess NaOH)

Question 20

When investigating the metal ion

Answer 20

You add a small volume of dilute sodium hydroxide to a solution of substance.

Question 21

When investigating the non-metal ions, Cl, Br and I.

Answer 21

Acidify with dilute nitric acid and then acid silver nitrate solution.

Question 22

Chlorine precipitate

Answer 22

White

Question 23

Bromine precipitate

Answer 23

Cream

Question 24

Iodine precipitate

Answer 24

Yellow

Question 25

Sulphate precipitate

Answer 25

White

Question 26

When investigating the non-metal ion, SO4 2-

Answer 26

Acidify and add barium chloride / nitrate solution

Question 27

Calcite formula

Answer 27

CaCO3

Question 28

Quartz formula

Answer 28

SiO2

Question 29

How can we test if hydrogen is present when putting a metal into dilute acid?

Answer 29

The squeaky pop test, through the use of a burning splint

Question 30

Why does copper not react with dilute acids at all?

Answer 30

Because it is less reactive than hydrogen

Question 31

Hydrochloric acid will always produce what kind of salt?

Answer 31

Chloride salts, e.g:

Magnesium chloride

Aluminium chloride

Zinc chloride

Question 32

Sulfuric acid will always produce what kind of salt?

Answer 32

Sulfate salts, e.g:

Magnesium sulfate

Aluminium sulfate

Zinc sulfate