Acetylene (c2h2) undergoes combustion in excess oxygen to generate gaseous carbon dioxide and water. given δh°f[co2 (g) ] = - 393.5 kj/mol, δh°f[h2o (g) ] = - 241.8 kj/mol, and δh°f[c2h2 (g) ] = 226.6 kj/mol, how much energy is released (kj) when 10.5 moles of acetylene is burned?

Question

Chemistry

Abbigail Mcmillan

21 April, 14:03

Acetylene (c2h2) undergoes combustion in excess oxygen to generate gaseous carbon dioxide and water. given δh°f[co2 (g) ] = - 393.5 kj/mol, δh°f[h2o (g) ] = - 241.8 kj/mol, and δh°f[c2h2 (g) ] = 226.6 kj/mol, how much energy is released (kj) when 10.5 moles of acetylene is burned?

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Peep · Answer 1

Answer is: 13181,7 kJ of energy is released when 10.5 moles of acetylene is burned.

Balanced chemical reaction: C₂H₂ + 5/2O₂ → 2CO₂ + H₂O.

ΔHrxn = sum of ΔHf (products of reaction) - sum of ΔHf (reactants).

Or ΔHrxn = ∑ΔHf (products of reaction) - ∑ΔHf (reactants).

ΔHrxn - enthalpy change of chemical reaction.

ΔHf - enthalpy of formation of reactants or products.

ΔHrxn = (2· (-393,5) + (-241,8)) - 226,6 · kJ/mol.

ΔHrxn = - 1255,4 kJ/mol.

Make proportion: 1 mol (C₂H₂) : - 1255,4 kJ = 10,5 mol (C₂H₂) : Q.

Q = 13181,7 kJ.