Types of Chemical Reactions

What is an exothermic reaction?

• A reaction that absorbs energy.

• A reaction that releases energy.

• A reaction that happens by itself.

• A reaction that contains energy.

What is an endothermic reaction?

• A reaction that absorbs energy.

• A reaction that releases energy.

• A reaction that happens by itself.

• A reaction that contains energy.

What is a spontaneous reaction?

• A reaction that absorbs energy.

• A reaction that releases energy.

• A reaction that happens by itself.

• A reaction that contains energy.

Can a chemical change be reversed?

• Yes

• No

Answer explanation

A chemical reaction cannot be reversed. This is because chemical bonds are broken and rearranged between atoms.

What product does iron and oxygen yield?

In other words, complete the following chemical reaction (word equation):

iron + oxygen -->

Answer explanation

When iron reacts with oxygen, it will yield iron oxide.

iron + oxygen --> iron oxide

This is actually the chemical reaction for rust.

Which of the following are indications that a chemical reaction has occurred?

- Check the boxes that apply

• colour change

• gas production

• change in odour

• change in size

• light

Answer explanation

The following are indications of chemical changes:

Remember that chemical changes are irreversible

- colour change

- gas production

- change in odour (smell)

- precipitate formation (a solid formed from two liquids being combined)

- emission of energy (e.g. light, heat, loud sound)

Physical changes are reversible changes in a substance. These include:

- changes in size

- changes in state of matter

- no new substances are created

What is a synthesis reaction?

• When a complex substance breaks down into new and simpler substances

• When there is one substance replacing another substance

• When simpler substances combine together and react to form a new and complex substance

• When two substances are switched after a chemical reaction occurs

What is a decomposition reaction?

• When a complex substance breaks down into new and simpler substances

• When there is one substance replacing another substance

• When simpler substances combine together and react to form a new and complex substance

• When two substances are switched after a chemical reaction occurs

What is a combustion reaction?

• When chemicals react with fire.

• An explosive reaction.

• fuel + oxygen --> water + carbon dioxide

• fuel + carbon dioxide --> water + oxygen

What type of reaction is this?

• a synthesis reaction

• a decomposition reaction

• a single replacement reaction

• a double replacement reaction

• a combustion reaction

Answer explanation

this is a decomposition reaction, because one complex substance is broken down into simpler substances after a reaction takes place