Topic 2 reactions

Question 1

What percentage of air is made up of oxygen

Answer 1

About 21%

Question 2

Give 2 properties of oxygen

Answer 2

Colourless
Odourless

Question 3

Name 2 uses of oxygen

Answer 3

Welding torches
Rocket fuel
Breathing apparatus in hospitals

Question 4

A reaction that uses oxygen is know as what type of reaction

Answer 4

An oxidation reaction

Question 5

Respiration uses oxygen and sugar and happens in our bodies - what is the equation

Answer 5

Sugar + oxygen —————> water + carbon dioxide + energy

Question 6

Rusting is an example of what type of reaction

Answer 6

Oxidation

Question 7

What is the word equation for rusting

Answer 7

Iron + oxygen + water —————> hydrated iron oxide

Question 8

Burning a fuel requires oxygen. What is the word equation

Answer 8

Fuel + oxygen———> carbon dioxide + water + energy

Question 9

What is another name for burning

Answer 9

Combustion

Question 10

What is the test for carbon dioxide

Answer 10

Turns limewater milky

Question 11

What is the test for water

Answer 11

Turns anhydrous copper sulfate from white to blue

Question 12

Hydrogen peroxide can be broken down to two products - what are they?

Answer 12

Water and oxygen

Question 13

What is added to speed up the break down of hydrogen peroxide

Answer 13

A catalyst (manganese dioxide)

Question 14

What is the test for oxygen

Answer 14

Relights a glowing splint

Question 15

What is a catalyst

Answer 15

A substance that speeds up a reaction but is not used up in the reaction

Question 16

Give an example of a biological catalyst

Answer 16

Enzymes eg protease, amylase, lipase

Question 17

Give 2 properties of hydrogen

Answer 17

Colourless
Odourless
Gas

Question 18

Give 2 uses of hydrogen

Answer 18

Making margarine
As a clean fuel e.g some buses are hydrogen fuelled
As rocket fuel

Question 19

What happens when magnesium is added to hydrochloric acid

Answer 19

It bubbles
Is exothermic reaction
Gives of hydrogen gas

Question 20

How can you test for hydrogen

Answer 20

Add a lighted splint and it burns with a squeaky pop

Question 21

What is the word equation for reaction between hydrochloric acid and magnesium

Answer 21

Magnesium + hydrochloric acid ————-> magnesium chloride + hydrogen

Question 22

What gas is now used in air ships after the hindenburg disaster

Answer 22

Helium

Question 23

Give 2 properties of carbon dioxide

Answer 23

Odourless
Colourless
Gas

Question 24

Give 2 uses of carbon dioxide

Answer 24

Fizzy drinks
Fire extinguisher
Dry ice

Question 25

Carbon dioxide can be made by adding calcium carbonate to hydrochloric acid. What is the word equation for this reaction

Answer 25

Calcium carbonate + hydrochloric acid ————-> calcium chloride + carbon dioxide + water

Question 26

How do you test for carbon dioxide

Answer 26

Turns limewater milky

Question 27

What is meant by an endothermic reaction

Answer 27

A reaction that takes in heat - the temperature will go down

Question 28

What is meant by an exothermic reaction

Answer 28

Gives out heat - the temperature will increase

Question 29

What is meant by thermal decomposition

Answer 29

Using heat to break down a substance

Question 30

Copper carbonate can be broken down by thermal decomposition. What is the colour change that happens

Answer 30

From green to black

Question 31

What is the black substance produced during the thermal decomposition of copper carbonated

Answer 31

Copper oxide

Question 32

What gas is produced by thermal decomposition of copper carbonate

Answer 32

Carbon dioxide is produced

Question 33

What is a reduction reaction

Answer 33

When oxygen is removed

Question 34

What is a redox reaction

Answer 34

When one substance is oxidised and another substance in the reaction is reduced

Question 35

In the redox reaction between sodium and magnesium oxide which substance is reduced?

Answer 35

Magnesium oxide has oxygen removed (reduced) to form magnesium

Question 36

In the redox reaction between magnesium oxide and sodium what are the products and state which is oxidised and which is reduced

Answer 36

Magnesium oxide + Sodium ————> magnesium + sodium oxide Magnesium oxide reduced Sodium oxidised - oxygen added

Question 37

What is meant by a reducing agent

Answer 37

The substance that reduces (removes the oxygen) from another substance e.g.sodium is reducing agent that removes the oxygen from magnesium oxide

Question 38

What is the termite reaction

Answer 38

An exothermic reaction between iron oxide and aluminium Example of a redox reaction The iron oxide is reduced The aluminium is oxidised

Question 39

Write the word equation for the thermite reaction

Answer 39

Aluminium + iron oxide ——————> aluminium oxide + iron