Physical and chemical changes

________________ are reversible and have some of the properties of their substance change

• Physical changes

• Chemical changes

• Reactants

• Products

_______________ are irreversible and have one or more new substances formed

• Physical changes

• Chemical changes

• Reactants

• Products

The signs of a chemical change are

• Temperature change

• Gas is produced

• Colour change

• Precipitate

• All of the above

A precipitate is

• When a gas is produced (usually also producing bubbles)

• The smallest particle of an element

• A solid formed from two solutions

• A metal which is malleable

Sodium + water -----> Sodium hydroxide +hydrogen

The product/s are

• Sodium

• Sodium + water

• Sodium hydroxide

• Sodium hydroxide + hydrogen

Iron + oxygen ----> Iron oxide

The reactant/s are

• Iron

• Iron + oxygen

• Iron oxide

• Iron + oxygen ---> Iron oxide

Which of the following is an example of a wanted chemical reaction?

• Cesium reacted with water

• Digestion

• Acid rain

• Chemical weapons

Which of the following is not an example of a physical change?

• Sour milk

• Dissolving sugar and water

• Chopping wood

• Boiling water

Which of the following is a chemical change?

• Shredding paper

• Breaking a glass

• Baking a cake

• Melting an ice cube

Which of the following is not an example of a chemical change?

• Melting of butter

• Burning a piece of paper

• Rusting of iron

• Fireworks