8Ib - Changing state

Question 1

Are combustion and neutralisation chemical or physical changes and why?

Answer 1

Changes such as combustion and neutralisation are chemical changes, because the atoms within substances become combined in different ways to form new substances.

Question 2

Are changes of state chemical or physical changes and why?

Answer 2

Changes of state are physical changes, because the chemicals in the substance do not change.

Question 3

What happens at melting and boiling points?

Answer 3

At melting points a liquid is formed, at boiling point evaporation happens within a liquid, if you cool a gas it condenses into a liquid.

Question 4

What happens to solids and liquids when heated?

Answer 4

Solid expands when it’s heated and expands even further when it forms a liquid. The volume of a substance changes with temperature. When ice forms it takes more space than water.