A solution of X with concentration $0.180\ \text{mol dm}^{-3}$ is made at $20^{\circ}\text{C}$. Calculate the average rate of reaction 1 over the first $1800\ \text{s}$.
Complete the rate equation for reaction 1.
Show that the rate constant, $k$, is $7.70 \times 10^{-4}\ \text{s}^{-1}$ at $20^{\circ}\text{C}$.
Calculate the initial rate for reaction 1 when the concentration of X is $0.150\ \text{mol dm}^{-3}$. Include units.
Platinum is a transition element. Explain why transition elements behave as catalysts.
Name the metal catalyst in the Haber process and explain why it is a heterogeneous catalyst.
Platinum acts as a heterogeneous catalyst in the removal of nitrogen dioxide, $\text{NO}_2$, from the exhaust gases of car engines. Describe the mode of action of a platinum catalyst in this process.
$\text{NO}_2$ acts as a homogeneous catalyst in the oxidation of atmospheric sulfur dioxide, $\text{SO}_2$. Write equations for the two reactions that occur.
$\text{SO}_2$ dissolves in water, giving $\text{H}_2\text{SO}_3$. $\text{H}_2\text{SO}_3$ can be oxidised under acidic conditions. The relevant electrode reaction and its $E^{\circ}$ value are shown: $\text{SO}_4^{2-} + 4\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2\text{SO}_3 + \text{H}_2\text{O}$, $E^{\circ} = +0.17\ \text{V}$. Four further half-equations for reactions under acidic conditions, together with their $E^{\circ}$ values, are shown: $\text{H}_3\text{BO}_3 + 3\text{H}^+ + 3e^- \rightleftharpoons \text{B} + 3\text{H}_2\text{O}$, $E^{\circ} = -0.73\ \text{V}$; $\text{BiO}^+ + 2\text{H}^+ + 3e^- \rightleftharpoons \text{Bi} + \text{H}_2\text{O}$, $E^{\circ} = +0.28\ \text{V}$; $\text{S} + 2\text{H}^+ + 2e^- \rightleftharpoons \text{H}_2\text{S}$, $E^{\circ} = +0.14\ \text{V}$; $\text{Sb} + 3\text{H}^+ + 3e^- \rightleftharpoons \text{SbH}_3$, $E^{\circ} = -0.51\ \text{V}$. Select the oxidising agent that could oxidise $\text{H}_2\text{SO}_3$ to $\text{SO}_4^{2-}$ ions under acidic conditions. Write an equation, and give the $E^{\circ}_{\text{cell}}$ value, for the reaction that takes place.