CIE Chemistry (US-0439): Specimen Questions with Answers 54 - 56 of 240

Question number: 54

Short Answer Question▾

Write in Short

The table shows some physical properties of the Group VII elements.

some physical properties of the Group VII elements

Some Physical Properties of the Group VII Elements

some physical properties of the Group VII elements

Use the information in the table to explain why

chlorine is a gas at room temperature, …………………………………………………………….

………………………………………………………………………………………………………………

Explanation

In there are covalent bonds between the atoms forming simple molecules. There are weak attractions between molecules of meaning little energy is needed to break these forces of attraction and therefore has a low boiling point. So the Force of attraction between them is very weak due to this it is gas.

Question number: 55

MCQ▾

Question

We use the term “relative” vapour density because

Choices

Choice (4) Response

a.

It is basically a measurement with respect to another gas

b.

It is easier to calculate

c.

It is a misnomer

d.

None of the above

Answer

a.

Explanation

We use the term “relative” vapour density because it is basically a measurement with respect to another gas.

Question number: 56

Short Answer Question▾

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Dibasic acids can form salts of the type and .

Malonic acid is a white crystalline solid which is soluble in water. It melts at 135 °C. The structural formula of malonic acid is given below. It forms salts called malonates

Or

  1. How could you determine if a sample of malonic acid is pure?

    technique used

Explanation

We should melt the sample of malonic acid at .