Chemical changes

Question 1

What is the reactivity series

Answer 1

Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum

Question 2

What happens when metals react with water

Answer 2

Reacts with water to form metal hydroxide and hydrogen gas

Metal + Water —> Metal Hydroxide + Hydrogen gas

Question 3

What happens when metals react with dilute acid

Answer 3

A salt and hydrogen are formed

Metal + Acid —> Salt + Hydrogen gas

Question 4

What happens when metals react with oxygen

Answer 4

Burn when heated as it reacts with oxygen
Copper forms a layer of copper oxide on the surface and doesn’t burn
Metal + Oxygen —> Metal Oxide

Question 5

What is displacement

Answer 5

When a reactive metal will take the place of a less reactive metal in a compound

Question 6

What is a redox reaction

Answer 6

When REDuction and OXidation takes place at the same time

Question 7

What are the metals that can be extracted using carbon and how does it work

Answer 7

Metals below carbon in the reactivity series can be extracted by reduction using carbon, e.g. Iron Oxide is reduced in a blast furnace to make iron

Question 8

What are the metals that can be extracted using electrolysis and how does it work

Answer 8

Metals above carbon in the reactivity series can be extracted by electrolysis
A current breaks it down

Question 9

What is the difference between an acid and alkaline

Answer 9

Acid - a substance that produces more hydrogen ions than hydroxide ions when dissolved in water
Alkaline - a substance that produces more hydroxide ions than hydrogen ions when dissolved in water

Question 10

What is neutral

Answer 10

A substance that is neither acid or alkaline

Question 11

How can you tell if a substance is acid or alkaline

Answer 11

Universal indicator
Litmus paper

Question 12

What are the three acids

Answer 12

Hydrochloric
Sulfuric
Nitric

Question 13

What is a base

Answer 13

A substance that reacts with an acid to neutralise it and produce a salt and water

Question 14

What happens when acids react with carbonates

Answer 14

A salt, water and carbon dioxide are produced when acids react with carbonates

Acid + Carbonate —> Salt + Water + Carbon Dioxide

Question 15

Required practical : Making soluble salts from insoluble substances

What is the method

Answer 15

Add powdered soluble reactant to acid in a beaker, one spatula at a time, stirring to mix. Continue adding until there’s excess
Filter mixture in the beaker to remove the excess powder. Collect filtrate
Pour filtrate into an evaporating basin and put on a roaring blue flame until small crystals appear on the edge

Question 16

What’s the difference between a strong and weak acid

Answer 16

Strong - ionise completely, all particles dissociate to release hydrogen ions
Weak - don’t fully ionise, only a small proportion of acid particles dissociate to release hydrogen ions (this is a reversible reaction)

Question 17

What is PANIC

Answer 17

Positive Anode Negative Is Cathode
Ions and electrodes are oppositely attracted

Question 18

What is half equation

Answer 18

An equation, involving electrodes and ions, that describe the process happening at an electrode

Question 19

What is OIL RIG

Answer 19

Oxidation Is Loss (of electrons)
Reduction Is Gain (of electrons)