Combustion end of unit revision

Combustion is a scientific word for:

• exploding

• burning

• evaporating

• getting hotter

The best way to put out a small electrical fire is:

• spray it with water to cool it down.

• spray with foam to exclude air and cool it down.

• cover with a wet cloth to exclude air and cool it down.

• spray with a powder extinguisher to exclude air.

During a chemical reaction, reactants form products. Compare the mass of reactants with the mass of products formed.

• The mass of reactants is greater than the mass of products.

• The mass of products is greater than the mass of reactants.

• The mass of products is the same as the mass of reactants.

• The change in mass depends on what the reactants and products are.

What does global warming mean?

• The warming effect of the Sun on the Earth.

• The natural warming effect caused by greenhouse gases in the atmosphere.

• The additional warming effect caused by increasing amounts of carbon dioxide in the air.

• The way the climate is changing as a result of more carbon dioxide in the air.

What is the independent variable in the candle experiment?

• Size of candle

• Height of block

• Size of container

• Time for candle to go out

What is the dependent variable in the candle experiment?

• Size of candle

• Height of block

• Size of container

• Time for candle to go out

Why do the other variables need to be controlled in the experiment?

• To ensure the experiment is fair

• To make the experiment faster

• To use less materials

• To make the experiment more fun

What is the missing word on the fire triangle?

• Water

• Heat

• Light

• Smoke

What does the fire triangle show?

• The three elements needed for a fire to start

• The three types of fire extinguishers

• The three stages of a fire

• The three colors of fire

How does water help to put a fire out?

• By cooling the fire and removing heat

• By adding oxygen to the fire

• By increasing the fuel supply

• By spreading the fire