Explain the meaning of these terms: 1. homogeneous catalyst 2. heterogeneous catalyst
Iodide ions react with peroxydisulfate ions. $2\text{I}^- + \text{S}_2\text{O}_8^{2-} \rightarrow \text{I}_2 + 2\text{SO}_4^{2-}$ This reaction is slow, but it is catalysed by $\text{Fe}^{2+}$ ions. Write two equations to show how $\text{Fe}^{2+}$ ions catalyse this reaction.
Suggest why the alternative route available in the presence of $\text{Fe}^{2+}$ ions has a smaller activation energy than the route without a catalyst.
Nitrogen monoxide reacts with oxygen. $2\text{NO}(g) + \text{O}_2(g) \rightarrow 2\text{NO}_2(g)$ This reaction is second order with respect to nitrogen monoxide and first order with respect to oxygen. Under certain conditions the value of the rate constant, $k$, is $8.60 \times 10^6\,\text{mol}^{-2}\,\text{dm}^6\,\text{s}^{-1}$. Construct the rate equation for this reaction.
Calculate the initial rate of the reaction under these conditions when the initial concentration of nitrogen monoxide is $7.20 \times 10^{-4}\,\text{mol dm}^{-3}$ and the initial concentration of oxygen is $1.90 \times 10^{-3}\,\text{mol dm}^{-3}$.
The drug cisplatin, $\text{Pt(NH}_3)_2\text{Cl}_2$, hydrolyses in water. $\text{Pt(NH}_3)_2\text{Cl}_2 + \text{H}_2\text{O} \rightarrow [\text{Pt(NH}_3)_2\text{Cl(H}_2\text{O)}]^+ + \text{Cl}^-$ The rate equation is shown. $\text{rate} = k[\text{Pt(NH}_3)_2\text{Cl}_2]$ The value of $k$ is $2.50 \times 10^{-5}\,\text{s}^{-1}$ under certain conditions. This reaction has a constant half-life. Explain why this is the case.
Use the information in this question to demonstrate that the half-life of this reaction is $2.77 \times 10^4\,\text{s}$.
$8.00 \times 10^{-6}$ moles of $\text{Pt(NH}_3)_2\text{Cl}_2$ are added to $100\,\text{cm}^3$ of water. Calculate the time taken for the concentration of $\text{Pt(NH}_3)_2\text{Cl}_2$ to decrease to $2.50 \times 10^{-6}\,\text{mol dm}^{-3}$.