Question

Consider the following data:

DeltaH (kj)

Ca(s) + 2C(graphite)----> CaC₂ (s) -62.8

Ca(s) + 1/2 O₂ (g) -----> CaO (s) -635.5

CaO (s) + H₂O(l) ----->Ca(OH)₂ (aq) -653.1

C₂H₂(g)+ 5/2 O₂(g)---->2CO₂(g)+H₂O(l) -1300

C(graphite)+ O₂(g)---->CO₂(g) -393.51

Use Hess' law to find the change in enthalpy at 25oC for this equation:

CaC₂(s)+2H₂O(l)-----> Ca(OH)₂ (aq)+ C₂H₂(g)

Answer 1

Ca(s) +20 (graphite) cac, (s) AHF – 62.8kJ - ca (s) + £2 (5) cao (5) H - - 635-5 ky ☺ cao (s) + Hoce) - CaCOH) cag) 4H- CaCOH), (99) 4.1 - - 653.1kJ -0 213) 2000)) + 10W) 4H -1200 II O 12 (3) + 5 2 (g) - 200(9) + 170 C graphite) to cs) - co c) 1 H2 – 39 3.51k. 2x -) 20 cgraphile) + 20 g) - 200, (g) AH=2x-spis 7 calz (s) -) cacs) + 2 graphite) CH- + 62.8 kJ cals) at 2020 - cacs) +20o (s) AH - 72 4.22kJ © +-) ca (s) + £20) - card (s) Alte – 635.5 kJ caols + roce) - calot, cac) Alt :-653.1 ks ca (s) + 120 etto) ca Coty car) At = - 1288.6 kJ ca C2 (5) +200) ) cales) + 200 (3) AH = -724.22kJ eads) + H Oce) +420) + cacoch, (ag) AH =-1206.661 cag(s) + Hole) 49.502 (3) ~) ca (011) (aq) +220)

Calz (s) + hoce) +2.50 (s) CaCOH) cap) +209031 AH- - 2012.82 kJ from @ 200269) + hoce - G" (s) +506) Alt = +1300les 0+0 Car2(5) +40 (0) +590) -7 ca Cot!),(ag) + 260 2.4 --2012.821 90, (1) +1008) 394,0+509) AH : 41200 kJ Cac (8) + 2 HO (1) - Ca (OH) (aq) + 2lt (o) AH=-712.82 kJ -) 414-712.8 kJ