Consider the exothermic reaction

2C2H6 (g) + 7O2 (g) →4CO2 (g) + 6H2O (g)

Calculate the standard heat of reaction, or ΔH∘rxn, for this reaction using the given data. Also consider that the standard enthalpy of the formation of elements in their pure form is considered to be zero.

Reactant or product

ΔH∘f (kJ/mol) C2H6 (g) - 84.7 CO2 (g) - 393.5 H2O (g) - 241.8

Express your answer to four significant figures and include the appropriate units.

Question

Chemistry

Evelyn Ewing

21 March, 16:22

Consider the exothermic reaction

2C2H6 (g) + 7O2 (g) →4CO2 (g) + 6H2O (g)

Calculate the standard heat of reaction, or ΔH∘rxn, for this reaction using the given data. Also consider that the standard enthalpy of the formation of elements in their pure form is considered to be zero.

Reactant or product

ΔH∘f (kJ/mol) C2H6 (g) - 84.7 CO2 (g) - 393.5 H2O (g) - 241.8

Express your answer to four significant figures and include the appropriate units.

+3

Answers (1)

Know the Answer?

Perla Mcbride · Answer 1

The answer to your question is - 2855 J

Explanation:

Reaction

2C₂H₆ + 7O₂ ⇒ 4CO₂ + 6H₂O

Formula

Heat of reaction = ΔHrxn = ΣΔHrxn products - ΣΔHrxn reactants

Substitution

ΔHrxn = { 4 (-393.5) + 6 (-241.8) } - {2 (-84.7) + 7 (0) }

ΔHrxn = {-1574 - 1450.8} - {-169.4}

ΔHrxn = - 3024.8 + 169.4

ΔHrxn = - 2855.4 J