For a particular isomer of c8h18, the combustion reaction produces 5104.1 kj of heat per mole of c8h18(g) consumed, under standard conditions. c8h18(g)+252o2(g)⟶8co2(g)+9h2o(g)δh ∘rxn=−5104.1 kj/mol what is the standard enthalpy of formation of this isomer of c8h18(g)?

Explanation:

Hello,

Considering the chemical reaction, the enthalpy of reaction is given by:

ΔH°rxn=ΔfHCO2+ΔfHH2O-ΔfHC8H18

(ΔfHO2=0)

Taking into account that the reaction produces energy, ΔH°rxn is negative. No, solving for ΔfHC8H18:

ΔfHC8H18=-ΔH°rxn+8*ΔfHCO2+9*ΔfHH2O

ΔfHC8H18=-(-5104.1 kJ/mol)+9*(-292.74kJ/mol)+8*(-393.5 kJ/mol)

ΔfHC8H18=-678.56 kJ/mol

Best regards.

A particular isomer of C₈H₁₈, whose combustion reaction produces 5104.1 kJ of heat per mole of C₈H₁₈(g) consumed, has a standard enthalpy of formation of -220.1 kJ/mol.

Let's consider the following thermochemical equation.

C₈H₁₈(g) + 25/2 O₂(g) ⟶ 8 CO₂(g) + 9 H₂O(g)   ΔH°rxn = −5104.1 kJ/mol

We can calculate the standard enthalpy of the reaction (ΔH°rxn) using the following expression.

where,

We will use this equation to calculate the standard enthalpy of formation of this isomer of C₈H₁₈.

A particular isomer of C₈H₁₈, whose combustion reaction produces 5104.1 kJ of heat per mole of C₈H₁₈(g) consumed, has a standard enthalpy of formation of -220.1 kJ/mol.

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its first and third is your answer i did the qustion the fourth isnt right