Chemistry 0620 · IGCSE · Alkenes

Alkenes — practice question

Alkenes form a homologous series of hydrocarbons produced when larger alkane molecules are cracked.
(a(i))[1]

Write down the general formula of alkenes.

(a(ii))[1]

Explain why larger alkane molecules need to be cracked.

(a(iii))[2]

Describe the two conditions required for cracking.

(b)[1]

Alkenes are unsaturated compounds. State what the term unsaturated means.

(c(i))[1]

Predict the boiling point of propene.

(c(ii))[2]

Deduce the physical state of butene at $-100^\circ\text{C}$. Give a reason for your answer.

(d)[1]

State how the volume of ethene in the gas syringe changes when the temperature is lowered and the pressure stays the same.

(e(i))[1]

State what is meant by exothermic.

(e(ii))[1]

Explain how this reaction pathway diagram shows that the reaction is exothermic.

(f(i))[2]

Finish the symbol equation for this reaction.\n\n$\text{C}_2\text{H}_4 + [BLANK] \rightarrow [BLANK]$

(f(ii))[1]

Choose the word that names the type of catalyst used in this reaction.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: $\text{C}_n\text{H}_{2n}$

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