Chemical reactions | Exit Quiz | Oak National Academy

Which two are signs that a chemical reaction has taken place?

• A colour change occurred.

• A new product was formed.

• The substance changed state.

• The substance was broken into smaller pieces.

• The substances were mixed together.

A substance changes from a gas to a liquid. This is a ___ change.

Select the correct word equation for the following reaction: propane and oxygen react together to produce carbon dioxide and water.

• carbon dioxide + water → propane + oxygen

• carbon dioxide + water = propane + oxygen

• propane + oxygen → carbon dioxide + water

• propane + oxygen = carbon dioxide + water

To balance a symbol equation…

• the number of atoms of each element must be equal on both sides.

• the number of atoms of each element must be higher in the products than the reactants.

• the number of atoms of each element must be lower in the products than the reactants.

Match the type of chemical reaction to the equation.

• displacement

• nickel + oxygen → nickel oxide

• decomposition

• magnesium carbonate → magnesium oxide + carbon dioxide

• neither displacement nor decomposition

• copper oxide + zinc → zinc oxide + copper

What is the balanced symbol equation for copper + oxygen → copper oxide?

• 
• 
• 
•