(G) Fuels

Question 1

What types of fuels are there?

Answer 1

• Alcohols
• Foods
• Hydrocarbons

Question 2

What alcohols are fuels?

Answer 2

• Methanol
• Ethanol
• Propanol
• Butanol
• Pentanol

Question 3

What foods are fuels?

Answer 3

• Carbohydrates
• Lipids
• Protein

Question 4

What are hydrocarbons?

Answer 4

A substance made of only hydrogen and carbon

Question 5

What hydrocarbons are fuels?

Answer 5

• petrol
• paraffin
• wax

Question 6

What is combustion?

Answer 6

Combustion is when a substance reacts rapidly with oxygen and releases heat and energy

Question 7

What kind of reaction is the combustion of fuels?

Answer 7

Exothermic - releases energy

Question 8

What is the equation of the combustion of fuels?

Answer 8

fuel + oxygen → carbon dioxide + water (+ heat energy)

Question 9

Factors that affect what fuel to select

Answer 9

• How easy it is to ignite
• How easy it is to store
• How easy it is to transport
• How much/type of pollution it produce

Question 10

What are hazards?

Answer 10

A source of harm such as a chemical

Question 11

What are risks?

Answer 11

A probability that a accident occurs

Question 12

Types of hazards

Answer 12

• Flammable
• Risk of Explosion
• Toxic
• Pollution

Question 13

What is flammability?

Answer 13

Chemicals/Fuels that can catch fire easily

Question 14

What is toxicity?

Answer 14

Chemicals/Fuels that are toxic or chemicals (like most fuels) contain impurities

Question 15

What polluting occurs from sulphur impurities?

Answer 15

Products from combustion can create impurities

Question 16

What are joules?

Answer 16

The unit of measurement for energy

Question 17

What is the symbol of joules?

Answer 17

J

Question 18

What are kilojoules?

Answer 18

The unit of measurement for energy but is 1000 times larger, for example;
1kJ = 1000J

Question 19

What are calories and it’s symbol?

Answer 19

The unit of measurement for energy in food and the symbol is cal

Question 20

What is specific heat capacity?

Answer 20

Specific heat capacity is the amount of energy it takes to increases the temperature of a substance

Question 21

What is the specific heat capacity of water?

Answer 21

It takes 4.2J/kg°C

Question 22

What is the unit of specific heat capacity?

Answer 22

J/kg°C

Question 23

What is the word equation of heat energy?

Answer 23

heat energy = mass of water × specific heat capacity of water × temperature rise
of water

Question 24

What is the symbol equation of heat energy?

Answer 24

q = m x c x ΔT
q= heat energy
m = mass
c = specific heat capacity of water
ΔT = temperature rise of water

Question 25

What is the equation for moles?

Answer 25

Mass= Moles x RFM

Question 26

How to calculate heat energy released from a fuel in kJ mol-1.?

Answer 26

heat of combustion (kJ mol -1) =
( heat energy supplied to water (kJ) x relative molecular mass of fuel )
/
mass of fuel burnt (g)

*note convert heat energy supplied to water to kJ