Which of the below correctly stated the composition of air?

• Carbon Dioxide 21%, Oxygen 78%, other gases 1%

• Nitrogen 78%, Oxygen 21%, other gases 1%

• Nitrogen 21%, Oxygen 78%, other gases 1%

• Carbon Dioxide 78%, Oxygen 21%, other gases 1%

Metals combined with oxygen to form

• metal hydroxide

• metal monoxide

• metal dioxides

• metal oxides

Rusting occur only on surfaces of

• iron and its alloy

• zinc and its alloy

• zinc and aluminium

• iron and zinc

When rusting takes place _________ oxide is formed

What factors that are required for rusting to takes place?

• oxygen & hydrogen

• salt & oil

• water & hydrogen

• water & oxygen

Which of the statement below is INCORRECT about rusting?

• Rust can shortened the lifespan of the affected object

• Rust can increase the mass of the metal and make the metal stronger

• Rust does not conduct electricity easily

• Rust is less magnetic compare to iron metal

By using ______________ to control the moisture level may help to reduce the process of rusting

_____________ is a process where zinc is used to coat the surface of the iron through electrolysis to prevent rusting.

After some weeks, which test tube will show that the iron nail will rust?

• C, D, E

• A, D, E

• A, B, C, E

• B, C, D, E

Which test tube will show the iron to rust the fastest?

• A

• B

• C

• D

• E