Chemistry 5070 · O Level · Reversible reactions and equilibrium

Reversible reactions and equilibrium — practice question

When the temperature is high, hydrogen combines with iodine to produce hydrogen iodide. $\text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\text{HI}(g) \qquad \Delta H = +53.0\ \text{kJ mol}^{-1}$
(a(i))[2]

Describe and explain the effect, if any, on the equilibrium position when the pressure is increased.

(a(ii))[2]

Describe and explain the effect, if any, on the equilibrium position when the temperature is decreased.

(b(i))[1]

Hydrogen iodide reacts with water to give the strong acid, hydriodic acid, HI(aq). What is meant by the term strong acid?

(b(ii))[1]

Construct the equation showing hydrogen iodide molecules dissociating into ions.

(c)[1]

Hydrogen iodide reacts with ethene to produce iodoethane: $\text{CH}_2{=}\text{CH}_2 + \text{HI} \rightarrow \text{CH}_3\text{CH}_2\text{I}$. What is the name of this type of reaction?

(d(i))[1]

How does the boiling point alter as the number of carbon atoms in the formula of the alkenes increases?

(d(ii))[1]

What physical state is butene in at $-7^\circ\text{C}$? Explain your answer.

(d(iii))[1]

Why is it difficult to predict the melting point of propene from the table information alone?

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