Questions

• Answer

  (a) = CO2 is a gas therefore there is more disorder

  (b) = 0K

  Question

  
• Answer

  M1 ΔH = (3 ͯ– 394) –(–1669 x 2) correct expression

  M2 = 2156 (kJ mol–1 ) M2 if –2156

  M3 ΔS = (28 x 4 + 214 x 3) – (51 x 2 + 6 x 3) M3 correct expression 1 M4 = 634 (J K–1 mol –1 )

  M4 if – 634

  M5 ΔG= ΔH – T ΔS or ΔH =T ΔS or T = ΔH ÷ΔS M5 expression or rearranged expression or with numbers 1

  M6 ΔS = 0.634 kJ K–1mol –1 M6 ΔS = M4 ÷ 1000

  M7 T = = 3400 to 3401 (K)


  Question

  Use the equation and the data in the table below to calculate the minimum temperature, in K, at which this reaction becomes feasible. (7marks)

  
• Answer

  M1 ΔsolH = ΔLEdissociationH + ΔhydH (Ca2+) + 2x ΔhydH (Br– ) or M1 – 110 = 2176 + (– 1650) + 2x ΔhydH (Br– )

  M2 (2x ΔhydH (Br– )) = – 636

  M3 ΔhydH (Br– ) = – 318 (kJ mol–1 )

  Question

  Q: Use the data in Table 4 to calculate the enthalpy of hydration, in kJ mol–1 , of bromide ions.