Grade 9 term 4 test

An alloy is...

• a metal combined with other materials; the properties of the metals are the same.

• a metal combined with other materials; the properties of the metals are changed.

• a non-metal combined with other materials; the properties of the metals are the same.

• a metal combined with oxygen; the properties of the metals are the same.

Ferric dioxide is the most common form of corrosion.

• True

• False

Metals can be divided into two groups: ferrous metals (metals that do not contain iron) and non-ferrous metals (metals that contains iron).

• True

• False

Which one of the following metal preserving methods is the most commonly used?

• Anodizing

• Painting

• Galvanizing

• Electroplating

Zinc is used in galvanising because...

• it is resistant to corrosion

• it is resistant to wear and tear

• it is fire and water resistant

• it is heat resistant

Which set of metals are most commonly used to electroplate jewelry?

• Tin and copper

• Platinum and silver

• Tin, Chromium and Copper

• Gold, platinum and Silver

State the type of food preservation method best suited for the food item shown in the picture:

• pasteurisation

• drying

• pickling

• salting

State the type of food preservation method best suited for the food item shown in the picture:

• pasteurisation

• sun drying

• pickling

• salting

Why is salt added to food?

• To speed up the rate at which food improves.

• To slow down the rate at which food decays and rots.

• To speed up the rate at which food decays and rots.

• To slow down the rate at which food can be consumed.

Salting prevents:

• bacteria, yeast and fungus from surviving in food.

• bacteria and yeast from surviving in food.

• yeast and mold from surviving in food.

• bacteria, yeast and mold from dying in food.