Name three metal catalysts used in catalytic converters.
Explain what is meant by a heterogeneous catalyst.
Explain what is meant by the term entropy of a system.
Using the information in Table 5.1, calculate $\Delta G^{\circ}$ for reaction 2 at $25\,^{\circ}\text{C}$. Show your working. Reaction 2: $\text{HNCO(g)} + \text{H}_2\text{O(g)} \rightarrow \text{NH}_3\text{(g)} + \text{CO}_2\text{(g)}$.
The ammonia produced in reactions 1 and 2 can then be used to remove nitrogen dioxide from exhaust gases. Reaction 3: $8\text{NH}_3 + 6\text{NO}_2 \rightarrow 7\text{N}_2 + 12\text{H}_2\text{O}$. Use the equations for reactions 1, 2 and 3 to derive an overall equation for the reduction of $\text{NO}_2$ by $(\text{NH}_2)_2\text{CO}$.
Isocyanic acid, $\text{HNCO}$, can form cyanuric acid, $\text{C}_3\text{H}_3\text{N}_3\text{O}_3$, under suitable conditions. $\text{C}_3\text{H}_3\text{N}_3\text{O}_3$ has a cyclic arrangement with alternating carbon and nitrogen atoms in the ring system. Suggest a structure for cyanuric acid.
Isocyanic acid, $\text{HNCO}$, is a weak acid. $\text{HNCO} + \text{H}_2\text{O} \rightleftharpoons \text{H}_3\text{O}^+ + \text{NCO}^-$. Write the mathematical expressions for $\text{p}K_a$ and pH.
Calculate the pH of $0.120\,\text{mol dm}^{-3}$ $\text{HNCO(aq)}$. Give your answer to three significant figures.
Calculate the percentage of $\text{HNCO}$ molecules ionised in $0.120\,\text{mol dm}^{-3}$ $\text{HNCO}$.