Home / iGCSE Chemistry (0620) Core:1.2 Diffusion: Exam Style Questions Paper 1

iGCSE Chemistry (0620) Core:1.2 Diffusion: Exam Style Questions Paper 1

iGCSE Chemistry (0620) Core Paper 1 - All Chapters
Question

In which states of matter does diffusion occur readily?

A) gases and liquids
B) gases only
C) liquids and solids
D) solids only

▶️ Answer/Explanation
Solution

Ans: A

Diffusion occurs most readily in gases because the particles are far apart and move rapidly. It also occurs in liquids, though more slowly, because liquid particles can move past each other. In solids, diffusion is extremely slow because particles are locked in fixed positions and can only vibrate.

Therefore, the correct answer is A (gases and liquids), as diffusion occurs readily in both these states, though at different rates.

Question

Which arrow represents evaporation?

▶️ Answer/Explanation
Solution

Ans: B

Evaporation is the process where a liquid changes to a gas. In the given options, we’re looking for the arrow that goes from liquid to gas. Since option B is the only one mentioned between liquid and gas (as we can see from the labels), it must represent evaporation.

Question

‘The movement of a substance very slowly from an area of high concentration to an area of low concentration.’
Which process is being described?

A a liquid being frozen

B a solid melting

C a substance diffusing through a liquid

D a substance diffusing through the air

▶️Answer/Explanation

Ans:C

The process of a substance diffusing through a liquid refers to the movement of particles or molecules from an area of higher concentration to an area of lower concentration within the liquid medium. Diffusion occurs due to the random motion of particles and is driven by the goal of achieving equilibrium, where the concentration of the substance becomes uniform throughout the liquid.

Question

Gases are separated from liquid air by fractional distillation.
The boiling points of four gases are shown.
Which gas is both monoatomic and a liquid at \(–200^o\) C?

▶️Answer/Explanation

Ans: A

As boiling point of Ar is \(–186^o\) C, which is higher than \(–200^o\) C. It will still be liquid. Ar is monoatomic. 

Nitrogen is diatomic.

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