This question is about the energy changes that take place during chemical reactions. (a) Nitrogen reacts with oxygen to make nitrogen monoxide. The reaction is endothermic. N₂(g) + O₂(g) → 2NO(g) Draw, on the axes provided in Fig. 6.1, the reaction pathway diagram for this reaction. Include labels for the: • axes • reactants • product • enthalpy change of reaction, ΔH • activation energy, Ea [Figure 6.1]

1. (a)Nitrogen reacts with oxygen to make nitrogen monoxide. The reaction is endothermic. N₂(g) + O₂(g) → 2NO(g) Draw, on the axes provided in Fig. 6.1, the reaction pathway diagram for this reaction. Include labels for the: • axes • reactants • product • enthalpy change of reaction, ΔH • activation energy, Ea[5]
2. (b)Hydrogen reacts with bromine to make hydrogen bromide. H—H + Br—Br → 2H—Br Calculate the enthalpy change of this reaction. Use the bond energies in Table 6.1. [Table 6.1] enthalpy change of reaction[3]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.