CIE Chemistry (US-0439): Specimen Questions with Answers 51 - 53 of 240

Question number: 51

MCQ▾

Question

Which element is a transition metal?

Choices

Choice (4) Response

a.

Table of Transition metal: Choice A

Table of Transition Metal: Choice A

Table of Transition metal

b.

Table of Transition metal: Choice B

Table of Transition Metal: Choice B

Table of Transition metal

c.

Table of Transition metal: Choice C

Table of Transition Metal: Choice C

Table of Transition metal

d.

Table of Transition metal: Choice D

Table of Transition Metal: Choice D

Table of Transition metal

Answer

d.

Explanation

Correct option is D because nickel is a transition metal and have melting point of element and color of its chloride is yellow.

Question number: 52

Short Answer Question▾

Write in Short

The alkanes are a homologous series of hydrocarbons.

Alkanes can be cracked to form alkenes and smaller alkanes. State the conditions needed for cracking.

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

Explanation

Cracking is the breakdown of a large alkane into smaller, more useful alkanes and alkenes. Simply put, hydrocarbon cracking is the process of breaking a long-chain of hydrocarbons into short ones. This process might require high temperatures and high pressure. As shown in the diagram:

condition to crack alkanes

Condition to Crack Alkanes

condition to crack alkanes

Question number: 53

MCQ▾

Question

Which of the following hydrocarbon is an alkane?

Choices

Choice (4) Response

a.

b.

c.

d.

Answer

c.

Explanation

  • Alkanes are the simplest and least reactive hydrocarbon species containing only carbons and hydrogens
  • Alkane consists of hydrogen and carbon atoms arranged in a structure in which all the carbon-carbon bonds are single

  • Alkanes have the general chemical formula

  • The members of the series (in terms of number of carbon atoms) are named as follows:
  1. methane, CH4 – one carbon and four hydrogen
  2. ethane, C2H6 – two carbon and six hydrogen
  3. propane, C3H8 – three carbon and 8 hydrogen
  4. butane, C4H10 – four carbon and 10 hydrogen
  5. pentane, C5H12 – five carbon and 12 hydrogen
  6. hexane, C6H14 – six carbon and 14 hydrogen