Module 2

Question 1

What do all chemical reactions produce?

Answer 1

A new substance

Question 2

In a word equation what side should a reactant appear on?

Answer 2

The left

Question 3

In a word equation what side should a product appear on?

Answer 3

The right

Question 4

In a word equation what should be used instead of an = sign

Answer 4

An arrow

Question 5

In a word equation what are the state symbols?

Answer 5

Solid (s)
Liquid (l)
Gas (g)
Aqueous (aq)

Question 6

What is an aqueous?

Answer 6

A substance dissolved in water

Question 7

How are state symbols written in a word equation?

Answer 7

In subscript

Question 8

What is the word equation for carbon dioxide? (example of a word equation)

Answer 8

Carbon(g) + oxygen(g) —> carbon dioxide(g)

Question 9

Energy is given out in…

Answer 9

An exothermic reaction

Question 10

What happens to the temperature in an exothermic reaction?

Answer 10

It increases

Burning is an example of an exothermic reaction.

Question 11

What happens to energy in an endothermic reaction?

Answer 11

The energy is taken in

Question 12

What happens to the temperature in an endothermic reaction?

Answer 12

It decreases

Electrolysis is an example of an endothermic reaction.

Question 13

Explain electrolysis

Answer 13

It uses electricity to separate compounds into the elements they contain.

Question 14

What is a fuel?

Answer 14

A chemical burned to release energy

Question 15

What happens during the combustion of fuel?

Answer 15

Heat energy is given out

Question 16

Combustion is …

Answer 16

The term used to describe the burning of a fuel in the presence of oxygen

Question 17

When a fuel is burned, what does it react with in the air?

Answer 17

Oxygen

Question 18

What is the % of oxygen we breathe in?

Answer 18

21%

Question 19

What is the test for oxygen?

Answer 19

Relights a glowing splint

Question 20

What happens when carbon reacts with oxygen in the air?

Answer 20

It forms carbon dioxide

Carbon(s) + oxygen(g) —> carbon dioxide(g)

Question 21

What is the test for carbon dioxide?

Answer 21

Turns limewater milky

Question 22

What is the difference between incomplete and complete combustion?

Answer 22

The products of complete combustion are carbon dioxide and water. Incomplete combustion occurs when insufficient oxygen is present.

Question 23

Describe carbon monoxide gas.

Answer 23

Carbon monoxide gas is a colourless, ouderless toxic gas

Question 24

What is the Word equation for the combustion of hydrogen?

Answer 24

Hydrogen reacts with oxygen in the air to form water

Hydrogen(g) + oxygen(g) —> water(l)

Question 25

What is the test for hydrogen?

Answer 25

Hydrogen gas burns with a squeaky pop

Question 26

Why is hydrogen described as the fuel of the future?

Answer 26

Using renewable energy, water molecules can be split electrolysis to produce hydrogen and oxygen. The hydrogen reacts with oxygen to release energy (exothermic reaction) The only product of combustion is water.

Question 27

What are the fossil fuels?

Answer 27

Coal, oil and natural gas

Question 28

How was coal formed?

Answer 28

Millions of years ago giant plants died. Over the next million of years these plants were buried under water and dirt. HEAT and PRESSURE turned these dead plants into COAL.

Question 29

How were oil and natural gas formed?

Answer 29

Plankton died and were buried in the ocean floor and over time they were covered by layers of silt and sand. Over millions of years the remains turned to oil and gas due to enormous HEAT and PRESSURE. Today we drill though the layers of silt, sand and rock to reach rock formations containing oil and gas.

Question 30

What happens to fossil fuels in the air?

Answer 30

They undergo combustion with oxygen

Question 31

What are the products of combustion?

Answer 31

Carbon dioxide and water.

Question 32

What are hydrocarbons?

Answer 32

Molecules that only consist of carbon and hydrogen