S2 - Chemistry Block 1 Revision

Which of these are an example of a chemical reaction?

• Making some toast

• Boiling water

• Melting iron

• Making a cup of tea with sugar

Chemical reactions are ___________?

• Irreversible

• Reversible

What sign of a chemical reaction will be seen in this experiment?

• A gas will be made

• A precipitate will be made

• Heat will be released

• It will be endothermic

Which of these is a sign of a chemical reaction?

• Iron wool becomes lighter when burned

• Two liquids mixed together make a precipitate

• Zinc metal is melted to form electronics solder

• Salt is added to water

A precipitate being made is a sign of a chemical reaction, what is it?

• A insoluble solid formed when two liquids are mixed together

• When a clear liquid becomes coloured

• When a gas is made

• When a reaction is endothermic

What signs of a chemical reaction are there when a sparkler is used?

• Heat

• Light

• Gas made

• Precipitate made

An exothermic reaction is one where heat is?

• Heat released

• Heat taken in

An endothermic reaction is one where heat is?

• Heat released (it is hot)

• Heat taken in (it is cold)

Burning wood is an example of a exothermic or endothermic reaction?

• Exothermic

• Endothermic

Physical changes are ___________?

• Irreversible

• Reversible