CIE Chemistry (US-0439): Specimen Questions with Answers 211 - 212 of 240

Question number: 211

Short Answer Question▾

Write in Short

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

Molecular formula of malonic acid is .

When malonic acid is heated there are two products, carbon dioxide and a simpler carboxylic acid. Deduce the name and molecular formula of this acid.

[2 Marks]

Explanation

This acid melts at . , and at a higher temperature it rapidly decomposes into acetic acid and carbon dioxide and formula of this acid is and name is acetic acid.

Question number: 212

MCQ▾

Question

The following diagram shows a cup of tea.

Image of Cup of Tea

Image of Cup of Tea

Image showing the cup of tea

Which row describes the water particles in the air above the cup compared with the water particles in the cup?

Choices

Choice (4) Response

a.

Moving Faster- True, Closer together- True

b.

Moving Faster- True, Closer together- False

c.

Moving Faster- False, Closer together- True

d.

Moving Faster- False, Closer together- False

Answer

b.

Explanation

Correct option is B (move faster and not closer together) because water particles in air above the cup compared with the water particles in cup move faster and not closer together because in air vapour moves freely because force of attraction is less than force of attraction in cup.