Name: Class: Date:

The following questions are designed to investigate the understandings of some chemistry

concepts.

1. What do you understand by the following terms, and give an example for each term:

Term Definition/Understanding Example

Element

Compound

Mixture

Physical Change

Chemical Change

2. Tick (√) the appropriate boxes to indicate whether elements, compounds, and/or

mixtures can be separated by physical means and/or chemical means. More than one box

may be ticked.

Physical means Chemical means

Elements

Compounds

Mixtures

3. Classify each of the following as an element [E], a compound [C], or a mixture [M].

a) Gold f) Air

b) Water g) Carbon dioxide

c) Seawater h) Silver

d) Sugar i) Ice

e) A chocolate sundae j) A cheeseburger

4. Classify each of the following properties of matter as physical [P] or chemical [C].

a) Colour f) Reacts violently with chlorine

b) Density g) Good conductor of heat

c) Burns easily (flammable) h) Dissolves readily in water

d) Not affected by acids i) Melts at 145 °C

e) Boils at 450 °C j) Malleable

5. Classify each of the following changes in matter as physical [P] or chemical [C].

a) Grinding chalk into powder f) Burning gasoline

b) Dissolving salt in water g) Hammering gold into foil

c) Dissolving zinc in acid h) Melting ice

d) Tearing a piece of paper i) Digesting food

e) Stretching copper into wire j) Making hydrogen from water

6. Classify each of the pictures below by placing the correct label in the blanks provided

A = Elements B = Compound C = Mixture of elements

D = Mixture of compounds E = Mixture of elements and compounds

Note: Each circle represents an atom and each different colour represents a different kind of

atom. If two atoms are touching, then they are bonded together.

a) _____ b) _____ c) _____

d) _____ e) _____ f) _____

g) _____ h) _____ i) _____

j) _____ k) _____ l) _____

m) _____ n) _____ o) _____

7. Place a check in the appropriate column to indicate whether you think the change is

physical or chemical.

Change Physical Change

Chemical Change

Salt dissolves in water

Hydrochloric acid reacts with magnesium to produce hydrogen gas

A piece of copper is cut in half

A sugar cube is ground up

Water is heated and changed to steam

Iron rusts

Ethyl alcohol evaporates

Ice melts

Milk sours (goes bad)

Sugar dissolves in water

Sodium and potassium react violently with water

Pancakes cook on a griddle

Grass grows on a lawn

A tire is inflated with air

Food is digested in the stomach

Water is absorbed by a paper towel

Ethyl alcohol boils at 79 °C

Paper burns

Water freezes at 0 °C

Fireworks explodes

Panadol gives off carbon dioxide when added to water

Clouds form in the sky