Question

Calculate H^o for the following equations:

a. Zn_(s) + 2H⁺_(aq)                          Zn²⁺_(aq)   +    H_2(g)           

b. 2H₂S_{(g)    +} 3O_2(g)                         2SO_2(g)   + 2H₂O_(g)

c. 3Ni_(s)    + 2NO₃^-_(aq)   + 8H⁺_(aq)               3Ni²⁺_(aq) + 2NO_(g)   + 4H₂O_(l)

Answer 1

(a) Write the reaction as follows: Zn(s) +2H* (aq) → Zn2+ (aq) +H2(8) Enthalpy of the reaction is AHC = AH, (H) +AH; (Zn2+)- AH; (Zn)- 24H;(H*) = 0–153.9 kJ/mol-0-20) = –153.9 kJ/mol Therefore, the required solution is -153.9 kJ/mol ----------------- ------- (6) Write the reaction as follows: 2H,S(8)+202(8) —— 250, (8)+2H,0() Enthalpy of the reaction is AH = 244;(H2O) +24H; (502)-2A4; (H2S) - 24H;() = 2(-241.82 kJ/mol) +2(-296.83 kJ/mol) -2(-20.6 kJ/mo1)-20) = (-483.64 – 593.66+41.2) kJ/mol = -1036.1 kJ/mol Therefore, the required solution is -1036.1 kJ/mol - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Write the reaction as follows: 3Ni (s) + 2NO3- (aq) +8H+ (aq) 3N2+ (aq) +2NO(8) + 4H20(1) Enthalpy of the reaction is AHCO = 344; (N1 2+ )+24H; (NO)+44H; (H20)-344; (Ni) -2447 (NO3-) -844; (H+) = [3(-64)+2(90.25) +4(-285.83)-3(0)-2(-205)-8(0)] kJ/mol = (–192 +180.5-1143.32+410)kJ/mol = - 744.82 kJ/mol Therefore, the required solution is - 744.82 kJ/mol