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Module 2: Born Haber Cycles. Find the standard enthalpy of formation of ethane. Given the following enthalpies of combustion; C(s) = -393 KJ mol -1 H 2 (g) = -286 KJ mol -1 C 2 H 6 (g) = -1560 KJ mol -1. Step 1: Write equations for the data provided. C(s) + O 2 CO 2 (g)
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Module 2: Born Haber Cycles • Find the standard enthalpy of formation of ethane. Given the following enthalpies of combustion; • C(s) = -393 KJ mol-1 • H2(g) = -286 KJ mol-1 • C2H6(g) = -1560 KJ mol-1
Step 1: Write equations for the data provided • C(s) + O2 CO2(g) • H2(g) + ½ O2(g) H2O(l) • C2H6(g) + 7/2 O2 2CO2(g) + 3H2O(l)
Step 2: Write an equation for what you want to find. • 2C(s) + 3H2(g) C2H6(g) • Start your cycle with the left hand side of this equation.
Step 3: The Cycle Hf[C2H6] 2C(s) + 3H2(g) C2H6(g) 2Hc[C] 2CO2(g) + 3H2(g) Hc[C2H6] 3Hc[H2] 2CO2(g) + 3H2O(l)
Step 4: Calculation • Hf[C2H6(g)] = 2(-393) + 3(-286) + (1560) = -84 KJ mol-1