ICAS Chemical Sciences (Matter and Materials) 2

Question 1

Which of these is a chemical change?

Accepted Answer

An iron nail rusting

Answer

Rusting forms a new substance (iron oxide), so it is a chemical change.

Question 2

How do particles in a gas compare with particles in a solid?

Accepted Answer

They are far apart and move freely

Answer

Gas particles are widely spaced and move rapidly in all directions.

Question 3

Which is an example of sublimation?

Accepted Answer

Dry ice turning directly into gas

Answer

Sublimation is a solid changing directly into a gas without becoming a liquid.

Question 4

Which mixture can be separated using filtration?

Accepted Answer

Sand and water

Answer

Filtration traps insoluble solids like sand while the water passes through.

Question 5

A block has a mass of 40 g and a volume of 20 cm³. What is its density?

Accepted Answer

2 g/cm³

Answer

Density = mass ÷ volume = 40 ÷ 20 = 2 g/cm³.

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