Question

One mole of n-pentane on complete combustion under standard conditions liberates 3500 kJ of heat Heat of formation of n-pentane is
[AH; of CO2 = -390 kJ mol and AH, of H2O --285 kJ mor']
A) +145 kJ mol-1
B) +120 kJ mol-1
C)-90 kJ mol-1
D)-160 kJ mol-1​

Answer 1

Answer:

The Answer is C

Explanation:

Answer 2

Answer:

The heat of formation of n-pentane is -160 kJ/mol.

Explanation:

The reaction is shown below.

C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O

The heat of formation is the difference in the sum of standard enthalpy of reactants and products.

The heat of formation is calculated as follows.

ΔH(formation) = 5ΔH(CO₂)  + 6ΔH(H₂O) - ΔH(C₅H₁₂)

                       = 5×(-390) + 6×(-285) -(-3500)

                       = -160 kJ/mol

Thus, the heat of formation of n-pentane is -160 kJ/mol.

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