Chemistry3 8E Combustion

Question 1

What problems does acid rain cause?

Answer 1

One of

• Trees and plants die
• Freshwater animals die
• Damage to buildings and statues

Question 2

How can we reduce global warming?

Answer 2

Burn less fossil fuels by

• using buses, bicycles and walking
• using UK grown foods which don’t have to be transported from the other side of the world.
• buy less new stuff
• recycle glass, plastic and anything else the council will take away.
• eat less beef (fewer cows to fart!)
• wear a jumper rather than turning up the heating on colder days
• turn off lights/ sockets/ devices on standby ( ask parent first!)

Question 3

Name the gases which make acid rain when they dissolve in clouds.

Answer 3

Sulphur dioxide and Nitrogen oxides.

Question 4

What causes global warming?

Answer 4

Gases released by the burning of fossil fuels (mainly carbon dioxide) and methane gas.

Question 5

Name the 3 things needed for a fire to burn.

Answer 5

In any order
Heat
Oxygen
Fuel

Question 6

What is oxidation?

Answer 6

A reaction where something combines with oxygen.

Question 7

How can we prevent acid rain?

Answer 7

Either
New cars have to clean up their waste gases with a catalytic converter fixed to their exhaust.
Or
Power stations have been forced to clean up the gases they make before they are released into the air.

Question 8

Which acid gas is made inside a vehicle engine?

Answer 8

Nitrogen dioxide.

Question 9

What are the consequences of global warming?

Answer 9

One of 
Average world temperatures increase 
Polar ice caps and glaciers are melting
Sea levels are rising 
More wildfires in forests 
More drought or flash floods
More unpredictable and extreme weather conditions

Question 10

How do you test for water vapour given off in combustion?

Answer 10

Cobalt paper turns from blue to pink

OR

Cobalt chloride crystals go from white to pink when water is added.

Question 11

What is incomplete combustion?

Answer 11

Any one of

• the fuel only partly reacts with oxygen
• Burning without enough oxygen.
• Soot produced.
• Carbon monoxide made instead of carbon dioxide

Question 12

What is the fire triangle?

Answer 12

A shape with 3 sides each of which has something needed to keep a fire going.
(It is a model which tries to show that if you take one of the three away the fire will go out.)

Question 13

What kind of fire should you not put water on?

Answer 13

An electrical fire.

Use a dry powder or carbon dioxide fire extinguisher instead.

Question 14

Why shouldn’t you use water on burning oil?

Answer 14

The water turns to steam because the fire is hot. The steam expands and splashes burning oil.

Question 15

What causes acid rain?

Answer 15

Acid gases given off when fossil fuels are burnt in cars and power stations dissolve in the clouds. The rain that falls is a weak acid.

Question 16

What is a hydrocarbon?

Answer 16

A substance that contains only hydrogen and carbon.

Question 17

Say the word equation for the burning/combustion of magnesium in air

Answer 17

Magnesium + oxygen&raquo_space;> magnesium oxide

Question 18

What is a fuel?

Answer 18

Something that can be burnt to release hear energy.

Question 19

What is the law of conservation of mass?

Answer 19

The idea that mass is not gained or lost during a chemical reaction. You can only rearrange the particles you start with to make the products.

Question 20

How do you test for carbon dioxide given off in combustion?

Answer 20

The best answer has 2 parts to it

• Bubble this gas through limewater.
• The limewater will turns milky/cloudy.

Question 21

What is the equation for combustion?

Answer 21

Oxygen + fuel&raquo_space;» water + carbon dioxide