Name three metal catalysts that are used in catalytic converters.
Explain what the term heterogeneous catalyst means.
Explain what the term entropy of a system means.
Use the data shown in Table 5.1 to calculate $\Delta G^\circ$ for reaction 2 at $25\,^\circ\text{C}$. Show your working.
The ammonia produced in reactions 1 and 2 may then be used to remove nitrogen dioxide from exhaust gases, as shown.\nreaction 3: $8\text{NH}_3 + 6\text{NO}_2 \rightarrow 7\text{N}_2 + 12\text{H}_2\text{O}$\nUse the equations for reactions 1, 2 and 3 to construct an overall equation for the reduction of $\text{NO}_2$ by $(\text{NH}_2)_2\text{CO$}.
Isocyanic acid, HNCO, can form cyanuric acid, $\text{C}_3\text{H}_3\text{N}_3\text{O}_3$, under certain conditions. $\text{C}_3\text{H}_3\text{N}_3\text{O}_3$ has a cyclic structure with alternating carbon and nitrogen atoms in the ring system. Suggest a structure for cyanuric acid.
Isocyanic acid, HNCO, is a weak acid.\n$\text{HNCO} + \text{H}_2\text{O} \rightleftharpoons \text{H}_3\text{O}^+ + \text{NCO}^-$\n$pK_a = 3.70$ at $25\,^\circ\text{C}$.\nWrite the mathematical expressions for $pK_a$ and pH.
Calculate the pH of $0.120\,\text{mol dm}^{-3}$ HNCO(aq). Give your answer to three significant figures.
Calculate the percentage of HNCO molecules ionised in $0.120\,\text{mol dm}^{-3}$ HNCO.