Answer to Question #139785 in Chemistry for Hodan

Question

Determine ΔH for the following reaction.

C4H10 (g) + oxygen (g) carbon dioxide (g) + water (g

Answer 1

Solution:

The balanced chemical reaction:

C₄H₁₀(g) + 6.5O₂(g) = 4CO₂(g) + 5H₂O(g)

Table of standard enthalpy of formation:

(https://www.thoughtco.com/common-compound-heat-of-formation-table-609253)

ΔH_f(C₄H₁₀) = -124.7 kJ/mol

ΔH_f(CO₂) = -393.5 kJ/mol

ΔH_f(H₂O) = -241.8 kJ/mol

ΔH_f(O₂) = 0 kJ/mol

Hence,

ΔH_r = 5 × ΔH_f(H₂O) + 4 × ΔH_f(CO₂) - ΔH_f(C₄H₁₀) - 6.5 × ΔH_f(O₂)

ΔH_r = (5 × -241.8) + (4 × -393.5) - (-124.7) - (6.5 × 0) = -2658.3 kJ/mol

ΔH_r = -2658.3 kJ/mol

Answer: ΔH for the butane (C₄H₁₀) combustion reaction is -2658.3 kJ/mol.