C.5 Chemical Change

Question 1

What is the reactivity series?

Answer 1

A list of elements ordered by their reactivity

Question 2

How can metals be placed in order of their reactivity

Answer 2

Add the metals to water or acid and see which ones react the most vigorously

Question 3

What is the name for a reaction where oxygen in removed

Answer 3

Reduction

Question 4

Why is gold found in the Earths crust as the metal itself

Answer 4

It is unreactive

Question 5

What process is used to extract metals less reactive than carbon

Answer 5

Reduction with carbon

Question 6

What process is used to extract meatls more reactive than carbon

Answer 6

electrolysis

Question 7

Waht is an ore

Answer 7

A material containing enough metal in it for it to be economically worthwhile to extract the metal

Question 8

Name 2 ways to extract low grade ore

Answer 8

Phytomining and bioleaching

Question 9

What is a low grade ore

Answer 9

Rock with small amount of metal compound in it

Question 10

How is phytomining carried out

Answer 10

Phytomining uses plants to absorb metal compounds. The plants
are harvested and then burned to produce ash that contains metal
compounds.

Question 11

How is bioleaching carried out

Answer 11

Bioleaching uses bacteria to produce leachate solutions that contain metal compounds.
The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper
compounds by displacement using scrap iron or by electrolysis

Question 12

what is a displacement reaction

Answer 12

a reaction in which a more reactive metal takes the place of a less reactive metal in a compound

Question 13

Define oxidisation

Answer 13

Loss of electrons

Question 14

Define reduction

Answer 14

Gain of Electrons

Question 15

Define acid in term of ph and ions

Answer 15

less than pH 7
which release H+ ions in solution

Question 16

State 3 acids and their formula

Answer 16

• Hydrochloric acid HCl (aq) - Sulfuric acid H2SO4 (aq)
  -Nitric acid HNO3 (aq)

Question 17

What is a base

Answer 17

A metal oxide, hydroxide or carbonate that will react with an acid

Question 18

What is an alkali

Answer 18

A soluble base

Question 19

Which ions are always in an alkali solution

Answer 19

OH-

Question 20

What is a salt

Answer 20

A compound formed wuth some or all the hydrogen from an acid being replaced by a metal

Question 21

What type of salts to acids form

Answer 21

Hydrochloric acid produces chlorides
Sulfuric acid produces sulfates
Nitric acid produces nitrates

Question 22

Metal + acid

Answer 22

Salt + Hydrogen

Question 23

Metal Hydroxide + acid

Answer 23

salt +water

Question 24

metal carbonate + acid

Answer 24

salt + water+ carbon dioxide

Question 25

Metal + water

Answer 25

Metal hyroxide +hydrogen

Question 26

Metal + oxygen

Answer 26

Metal oxide

Question 27

How do you make a soluble salt from an acid

Answer 27

React it with a base

Question 28

If a salt is in a solution how do you exract it as a solid

Answer 28

Allow the water to evaporate

Question 29

What is corrosion

Answer 29

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

Question 30

What is necessary for rusting

Answer 30

water and air

Question 31

How can rusting be prevented

Answer 31

Using barrier coating, galavising, sacraficial protectioon

Question 32

3 examples of barrier coating

Answer 32

greasing, painting , elctroplating

Question 33

How does sacrificial protection work

Answer 33

A more reactive metal is corroded rather than the base metal