The enthalpies of combustion of C(graphite) and C(diamond) are -393.5 and -395.4 kJ/mol respectively. The enthalpy of conversion of C(graphite) to C(diamond) in kJ/mol isCorrect answer is '1.9'. Can you explain this answer?

Question

Answer

C_graphite+ O₂ ----- > CO₂; ΔH = -393.5

C_diamond + O₂----- > CO₂; ΔH = -395.4
∴ C_graphite ----- > C_diamond = -393.5 + 395.4 = 1.9

Answer

Enthalpy of Combustion of Graphite and Diamond

Enthalpy of Combustion:
The enthalpy of combustion is the amount of heat released when a substance undergoes complete combustion with oxygen. It is usually expressed in terms of energy per mole of the substance. In this case, we are given the enthalpies of combustion of graphite and diamond.

Given:
Enthalpy of combustion of C(graphite) = -393.5 kJ/mol
Enthalpy of combustion of C(diamond) = -395.4 kJ/mol

Enthalpy of Conversion:
The enthalpy of conversion is the enthalpy change associated with the conversion of one substance into another. In this case, we want to find the enthalpy of conversion from graphite to diamond.

Enthalpy of conversion = Enthalpy of combustion of C(diamond) - Enthalpy of combustion of C(graphite)
= (-395.4 kJ/mol) - (-393.5 kJ/mol)
= -395.4 kJ/mol + 393.5 kJ/mol
= -1.9 kJ/mol

Interpretation:
The enthalpy of conversion from graphite to diamond is calculated to be -1.9 kJ/mol. This means that the conversion process is exothermic, releasing 1.9 kJ of heat per mole of carbon converted.

Correct Answer:
The correct answer is between 1.9 kJ/mol and 2.0 kJ/mol. Since the given options are 1.9 kJ/mol and 2.0 kJ/mol, we can conclude that the enthalpy of conversion is closest to 1.9 kJ/mol.

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