LEV KS3 Y7 Chemical Reactions

In a chemical reaction, mass will:

• Increase

• Decrease

• Stay the same

What is needed for combustion?

• Fuel

• Heating

• Oxygen

• All of the above

What is the correct equation for combustion?

• Hydrocarbon + carbon dioxide $\rightarrow$ water + energy

• Hydrocarbon + Oxygen $\rightarrow$ carbon dioxide + water ( + energy)

• Energy + oxygen $\rightarrow$ Carbon dioxide + water

• Hydrocarbon + water $\rightarrow$ Oxygen + energy

Oxidation is :

• The loss of oxygen

• The gain of oxygen

When copper carbonate is heated it forms copper oxide and carbon dioxide. What type of reaction is this called?

• Oxidation

• Reduction

• Thermal decompostion

• Dispalcement reaction

A reaction that transfers energy to the surrounding is called what?

• Endothermic

• Exothermic

A reaction that takes in energy from the suroundings is called what?

• Endothermic

• Exothermic

What is the correct definition for a catalyst?

• A substance that slows down a chemical reaction without being changed or used up

• A substance that speeds up a chemical reaction but is changed or used up

• A substance that speeds up a chemical reaction without being changed or used up

The pH scale ranges from:

• 0-7

• 0-14

• 7-14

• 1-15

A substance with a pH below 7 is described as :

• an alkali

• neutral

• an acid