🤓 Based on our data, we think this question is relevant for Professor Yu's class at STATEN ISLAND CUNY.
Given the following data
Ca(s) + 2C (graphite) → CaC2 (s) ΔH = -62.8 kJ
Ca(s) + 1/2 O2 (g) → CaO (s) ΔH = -635.5 kJ
CaO (s) + H2O (l) → Ca(OH)2 (aq) ΔH = -653.1 kJ
C2H2 (g) + 5/2O2 (g) → 2CO2 (g) + H2O (l) ΔH = -1300. kJ
C(graphite) + O2 (g) → CO2 (g) ΔH = -393.5 kJ
Calculate ΔH for the reaction
CaC2 (s) + 2H2O (l) → Ca(OH)2 (aq) + C2H2 (g)
To determine the ΔH for the reaction, use Hess Law. Manipulate the individual reactions such that when you add them you arrive to the required reaction.
Required reaction: CaC2(s) + 2H2O(l) → Ca(OH)2(aq) + C2H2(g)
Reaction 1: Ca(s) + 2 C (graphite) → CaC2(s) (reverse reaction) ΔH = -62.8 kJ (reverse sign)
(Reverse the reaction because CaC2 is on the product side in the required reaction while it is in the reactant side in Reaction 2)