Inorganic chemistry - IGCSE

Question 1

Acid

Answer 1

Produces H+ ions in aqueous solutions
They have a pH range between 0 and 7
Acids are known as proton donors

Question 2

Base

Answer 2

A substance which reacts with an acid in a neutralisation reaction to form a salt and water only
Bases are known as proton acceptors

Question 3

Alkali

Answer 3

Produces OH- in aqueous solutions
They have a pH range between 7 and 14
Alkalis are soluble bases

Question 4

Alloy

Answer 4

A metal compound made by combining two or more metals together
This process is carried out to give greater strength or resistence to corrosion

Question 5

Ores

Answer 5

A type of rock which contains metals compounds
The metals or metal compounds are present in sufficient amounts to make it worth extracting them

Question 6

Combustion

Answer 6

The burning of a substance in oxygen
If there is sufficient oxygen present for the substance to burn then it is called complete combustion
Energy is transferred to the surroundings as heat and light

Question 7

Thermal decomposition

Answer 7

The breaking down of a compound by heating

Question 8

Corrosion

Answer 8

The destruction of materials by chemical reactions with substances in the environment

Question 9

Displacement

Answer 9

A chemical reaction in which a more reactive element displaces a less reactive element from its compound

Question 10

Neutralisation

Answer 10

The reaction in which an acid and a base react to form a salt and a water

Question 11

Greenhouse effect

Answer 11

The increase in the temperature of the Earth’s atmosphere due to the greenhouse gases in the atmosphere trapping infra-red radiation from the surface

Question 12

Greenhouse gases

Answer 12

Gases in the atmosphere which mantain temps on Earth high enough to support life
Greenhouse gases include water vapour, CO2 and methane

Question 13

Oxidation

Answer 13

Gain of oxygen or loss of electrons

Question 14

Oxidising agent

Answer 14

A species which brings about oxidation by gaining electrons
The oxidising agent itself is reduced

Question 15

Reduction

Answer 15

Loss of oxygen or gain or electrons

Question 16

Reducing agent

Answer 16

A species which brings about reduction by losing electrons
The reducing agent itself is oxidised

Question 17

Redox reaction

Answer 17

A reaction in which both oxidation and reduction occur

Question 18

Reduction with carbon

Answer 18

Process used to extract metals from their oxides when the metal is less reactive than carbon
The metal oxide is heated with carbon so it reduces the metal oxide to the metallic element

Question 19

pH scale

Answer 19

A measure of the acidity or alkalinity of a solution ranging from 0 to 14
The pH can be measured using universal indicator or a pH probe

Question 20

Indicators

Answer 20

A chemical used to distinguish between acidic and alkaline solutions
Examples include phenolphthalein, litmus and methyl orange
They are also used in titration reactions to indicate the end point of the reaction by a clear colour change

Question 21

Universal indicator

Answer 21

A mixture of dyes that changes colour gradually over a range of pH and is used in testing for acids and alkalis

Question 22

Rust

Answer 22

Reddish coating of iron oxide which forms on iron when it undergoes oxidation
Iron rusts when it is in the presence of oxygen and water

Question 23

Galvanise

Answer 23

A process used to protect against corrosion by coating the metal with a protective layer of zinc

Question 24

Sacrificial protection

Answer 24

The protection of iron or steel against corrosion by using a more reactive metal
Zinc is often used as a sacrificial metal
Sacrificial protection creates a physical barrier to oxygen and water, preventing corrosion of the metal