Combustion

Question 1

What is a hydrocarbon and what is it made up of?

Answer 1

A hydrocarbon is a chemical substance (molecule/compound), which contains only hydrogen and carbon atoms chemically bonded.

Question 2

Can hydrocarbons have a different amount of carbon/hydrogen atoms?

Answer 2

Yes

Question 3

What is the chemical formula of methane?

Answer 3

CH4

Question 4

What is the chemical formula of octane?

Answer 4

C8H18

Question 5

What is fuel?

Answer 5

Fuel is a substance that is burned to produce energy, heat and power.

Question 6

What are the three fossil fuels?

Answer 6

Coal, oil and gas

Question 7

What is one of the main sources of hydrocarbons?

Answer 7

Crude oil

Question 8

What is crude oil and how is it formed?

Answer 8

Crude oil is a mixture of different hydrocarbons, existing in liquid form. It is formed when carbon-based plant and animal organisms decompose and get buried underground under high pressure & temperature for millions of years.

Question 9

What is combustion?

Answer 9

Combustion is a chemical reaction between hydrocarbons and oxygen.

Question 10

What is the word equation for combustion?

Answer 10

hydrocarbon + oxygen -> carbon dioxide + water

Question 11

What is the (balanced) chemical equation for combustion?

Answer 11

CH4 + 2O2 -> CO2 + 2H2O

Question 12

What is the test for carbon dioxide and what is the sign of a positive test result?

Answer 12

• bubble gas through limewater
• water goes from clear to cloudy

Question 13

What is the test for water and what is the sign of a positive test result?

Answer 13

• add water to anhydrous copper sulphate
• turns white to blue

Question 14

What are some uses for hydrocarbons?

Answer 14

• fuelling boats/planes/cars etc.
• used for domestic heating and cooking

Question 15

What are the required conditions for combustion?

Answer 15

• fuel
• heat
• oxygen