Answer
A. -1305 kJ
Explanation
Given:
Equation: C2H4(g) + 302(g) ---- > 2C02(g) + 2H20(l).
Formation ΔH values:
for C2H4(g) = 52.30 kJ/mol,
for 02(g) = 0 kJ/mol,
for CO2(g) = -393.5 kJ/mol, and
for H20(1) = -285.8kJ/mol.
What to find:
The ΔHrxn from the ΔH of formation for the given reaction.
Step-by-step solution:
ΔHrxn = (Sum of ΔH formation for the product) - (Sum of ΔH formation for the reactants).
ΔHrxn = (ΔH for 2CO2(g) + ΔH for 2H2O(l)) + (ΔH for C2H4(g) + ΔH for 3O2(g))
ΔHrxn = [(2 x -393.5) + (2 x -285.8)] + [52.30 + (3 x 0)]
ΔHrxn =(-787.0 - 571.6) + (52.30 + 0)
ΔHrxn = -1358.6 + 52.30
ΔHrxn = -1306.3 kJ
so the closest answer is A. -1305 kJ
