Chemistry-Natures

Question 1

What is a fuel?

Answer 1

A fuel is a substance that burns releasing energy.

Question 2

What does combustion refer to?

Answer 2

Combustion is a chemical word for burning.

Question 3

What happens when a substance burns?

Answer 3

All the elements present are combined with oxygen to produce the relevant oxides.

Question 4

What is essential for combustion?

Answer 4

Oxygen is essential for combustion.

Question 5

What does the fire triangle represent?

Answer 5

The key elements needed for burning.

Question 6

What happens if one element of the fire triangle is removed?

Answer 6

The fire goes out.

Question 7

How do firefighters put out fires?

Answer 7

By removing one of the elements of the fire triangle.

Question 8

What effect does putting water on a fire have?

Answer 8

It removes the heat.

Question 9

Why is carbon dioxide used to extinguish fires?

Answer 9

It is heavier than oxygen, sinks, and stops oxygen getting in.

Question 10

What does cutting down trees in a forest fire do?

Answer 10

It removes fuel.

Question 11

What is a hydrocarbon?

Answer 11

A molecule that contains carbon and hydrogen.

Question 12

What is produced when a hydrocarbon is burned in a plentiful supply of oxygen?

Answer 12

Carbon dioxide and water (complete combustion).

Question 13

What is produced during incomplete combustion of a hydrocarbon?

Answer 13

Carbon monoxide, soot (unburnt carbon), carbon dioxide, and water.

Question 14

What are fossil fuels, and how long did they take to form?

Answer 14

Fossil fuels such as coal, oil, and gas took millions of years to form and are finite.

Question 15

What gas is produced by burning fossil fuels that contributes to global warming?

Answer 15

Carbon dioxide, which is a greenhouse gas.

Question 16

What is the environmental benefit of using hydrogen as a fuel?

Answer 16

It only produces water and does not contribute to global warming.

Question 17

What is fractional distillation used for?

Answer 17

To separate crude oil into more useful fractions.

Question 18

What is cracking in the context of hydrocarbons?

Answer 18

A process that breaks up less useful large molecules into more useful smaller molecules.

Question 19

What prefix denotes 1 carbon in a hydrocarbon?

Answer 19

Meth

Question 20

What is the general formula of the alkanes?

Answer 20

CnH2n+2

Question 21

What family of hydrocarbons has at least one carbon to carbon double bond?

Answer 21

Alkenes.

Question 22

What is the general formula for alkenes?

Answer 22

CnH2n

Question 23

What defines cycloalkanes?

Answer 23

Carbons are joined in a cyclic manner with no carbon to carbon double bonds.

Question 24

What indicates that a hydrocarbon is unsaturated?

Answer 24

It has at least one carbon to carbon double bond.

Question 25

What test can be used to identify unsaturated hydrocarbons?

Answer 25

Add bromine water and shake; if unsaturated, it will decolourise rapidly.

Question 26

What are monomers?

Answer 26

Small subunits that make up plastics.

Question 27

What is polymerisation?

Answer 27

The process by which monomers are joined to form a polymer.

Question 28

What is a thermosetting polymer?

Answer 28

A polymer that cannot be reheated and reset after moulding.

Question 29

What is a thermoplastic polymer?

Answer 29

A polymer that can be remoulded on heating many times.

Question 30

What is the property of Polyvinylchloride (PVC)?

Answer 30

Rot proof.

Question 31

What is the use of PTFE (Teflon)?

Answer 31

Non-stick pans.

Question 32

What is the environmental issue related to plastics in landfill?

Answer 32

They take around 400 years to disappear.

Question 33

What is the effect of marine pollution on wildlife?

Answer 33

It can have devastating effects.

Question 34

True or False: Burning plastics can release carbon monoxide due to a shortage of oxygen.

Answer 34

True.