Chemistry

Question 1

What is limestone made from?

Answer 1

Calcium carbonate

Question 2

Where do you get limestone from?

Answer 2

It’s quarried out of the ground

Question 3

What is the formula for calcium carbonate?

Answer 3

CaCO3

Question 4

What happens when calcium carbonate is heated?

Answer 4

It thermally decomposes and becomes calcium oxide and carbon dioxide

Question 5

Word equation for thermal decomposition of calcium carbonate

Answer 5

Calcium carbonate - calcium oxide + carbon dioxide

Question 6

What happens when calcium carbonate reacts with an acid?

Answer 6

It makes calcium sulfate, carbon dioxide and water

Question 7

Word equation for reaction with calcium carbonate and an acid

Answer 7

Calcium carbonate + sulfuric acid - calcium sulfate + carbon dioxide + water

Question 8

What’s does calcium oxide react with to produce calcium hydroxide?

Answer 8

Water

Question 9

What happens when calcium oxide and water react?

Answer 9

Calcium hydroxide

Question 10

Word equation for calcium oxide and water

Answer 10

Calcium oxide + water - calcium hydroxide

Question 11

Is calcium hydroxide an acid or an alkali?

Answer 11

Alkali

Question 12

What can calcium hydroxide be used for?

Answer 12

To neutralise acidic soil in fields

Question 13

Why is calcium hydroxide better than powdered limestone for neutralising acidic soil?

Answer 13

It works much faster

Question 14

What can calcium hydroxide be used to test for?

Answer 14

Carbon dioxide

Question 15

How do you test for carbon dioxide with calcium hydroxide?

Answer 15

You make a solution of calcium hydroxide in water and bubble gas through it, the solution will turn cloudy if there’s carbon dioxide in the gas

Question 16

What are the products when calcium hydroxide and carbon dioxide react?

Answer 16

Calcium carbonate and water

Question 17

Word equation for calcium hydroxide and carbon dioxide

Answer 17

Calcium hydroxide + carbon dioxide - calcium carbonate + water

Question 18

How do you make cement?

Answer 18

You heat powdered limestone in a kiln with powdered clay

Question 19

How do you make mortar?

Answer 19

Mix cement with sand and water

Question 20

How do you make concrete?

Answer 20

Mix cement with sand and aggregate

Question 21

What are the two new methods for extracting copper from low grade ores?

Answer 21

Bioleaching and phytomining

Question 22

What is bioleaching?

Answer 22

It uses bacteria to separate copper from copper sulfide. The bacteria get energy from the bond between copper and sulfur, separating out the copper from the ore in the process. The leachate (solution produced by the process) contains copper, which can be extracted e.g. by filtering

Question 23

What is phytomining?

Answer 23

This involves growing plants in soil that contains copper. The plants can’t use or get rid of the copper so it gradually builds up in the leaves. The plants can be harvested, dried and burned in a furnace. The copper can be collected from the ash left in the furnace

Question 24

Why are noble gases unreactive?

Answer 24

Their atoms have stable arrangements of electrons

Question 25

Does the mass of products equal the mass of reactants?

Answer 25

Yes because during a chemical reaction no atoms are lost or made

Question 26

What is thermal decomposition?

Answer 26

Decomposing something by heating it

Question 27

What can calcium carbonate be decomposed to make?

Answer 27

Calcium oxide and carbon dioxide

Question 28

Do the carbonates of magnesium, calcium and sodium decompose on heating in a similar way?

Answer 28

Yes

Question 29

What does calcium oxide react with to produce calcium hydroxide?

Answer 29

Water

Question 30

What is produced when calcium oxide reacts with water?

Answer 30

Calcium hydroxide is produced

Question 31

Is calcium hydroxide an acid or an alkali?

Answer 31

Alkali

Question 32

What can calcium hydroxide be used for?

Answer 32

The neutralisation of acids

Question 33

Where are unreactive metals such as gold found?

Answer 33

In the earth as the metal itself

Question 34

How are most metals found?

Answer 34

As compounds that require chemical reactions to extract the metal

Question 35

How can metals that are less reactive than carbon be extracted from their oxides?

Answer 35

Reduction with carbon

Question 36

An example of an metal oxide that can be extracted through reduction with carbon

Answer 36

Iron oxide is reduce in the blast furnace to make iron

Question 37

How are metals more reactive than carbon extracted?

Answer 37

Electrolysis

Question 38

What's bad about electrolysis?

Answer 38

It requires a lot of energy | This makes it expensive

Question 39

How can copper be extracted?

Answer 39

From copper rich ores by heating the ores in a furnace (smelting)

Question 40

How can copper be purified?

Answer 40

Through electrolysis

Question 41

Is the supply of copper rich ores limited?

Answer 41

Yes

Question 42

What two new ways can copper be extracted fro low grade ores?

Answer 42

Bioleaching | Phytomining

Question 43

What is bioleaching?

Answer 43

Uses bacteria to separate copper from copper sulfide The bacteria gets energy from the bond between copper and sulfur, separating out the copper from the ore in the process The leachate contains copper which can be extracted by filtering

Question 44

What is the leachate in bioleaching?

Answer 44

The solution produced by the process which has copper in it

Question 45

How can copper be obtained from solutions of copper salts?

Answer 45

Electrolysis | Displacement using scrap iron

Question 46

Extracting aluminium and titanium are expensive because:

Answer 46

There are many stages in the process | Large amounts of energy are needed

Question 47

Why should we recycle metals?

Answer 47

Extracting them uses limited resources It's expensive in terms of energy It has negative environmental effects

Question 48

What does iron from the blast furnace contain?

Answer 48

96% pure iron

Question 49

What do the impurities in blast furnace iron make it?

Answer 49

Brittle so has limited uses

Question 50

Do oils dissolve in water?

Answer 50

No