11.4. The reactions of chlorine
A subsection of Chemistry, 9701, through 11. Group 17
Listing 10 of 290 questions
Chloramine, NH2Cl, can be used in the treatment of drinking water to kill bacteria. Excess chloramine in water is destroyed using UV light. The mechanism for this involves free radicals. The initiation step in this process is shown. UV NH2Cl ●NH2 + ●Cl What is meant by the term free radical ? The equation for a possible propagation step in the process is shown. NH2Cl + ●Cl ●NHCl + HCl Suggest an equation for a possible termination step in this process. Draw the ‘dot-and-cross’ diagram of NH2Cl. Show outer electrons only.  State the hybridisation of the nitrogen atom and suggest the H–N–Cl bond angle in the NH2Cl molecule. hybridisation of N H–N–Cl bond angle  Some values for standard enthalpy changes of formation, , and standard entropies, S o, are given in the table. / kJ mol–1 S o / J K–1 mol–1 NH2Cl +80.1 +241 NH3– 45.9 +198 N2H4+95.4 +237 HCl –92.3 +187 Define the meaning of the term entropy. Hydrazine, N2H4, can be produced from chloramine and ammonia as shown. NH2Cl + NH3N2H4+ HCl Calculate the standard entropy change, ΔS o, for this reaction. ΔS o = J K–1 mol–1 Calculate the standard enthalpy change, ΔH o, for this reaction.  ΔH o = kJ mol–1 Calculate the standard Gibbs free energy change, ΔG o, for this reaction at 298 K. ΔG o = kJ mol–1 Explain, with reference to ΔG o, why this reaction becomes less feasible at higher temperatures. Compare and explain the basicities of ammonia, ethylamine and phenylamine. 
9701_w18_qp_42
THEORY
2018
Paper 4, Variant 2
View
Questions Discovered
290