Calculating Heat of Combustion for Naphthalene

Explanation:

To calculate the heat of combustion of naphthalene, follow these steps:

Step 1: Calculate the molar mass of naphthalene.

The molar mass of carbon (C) is 12.01 g/mol.

The molar mass of hydrogen (H) is 1.01 g/mol.

The molar mass of naphthalene (C10H8) is obtained by multiplying the molar mass of carbon by 10 and the molar mass of hydrogen by 8, then summing these values:

Molar mass of naphthalene = (12.01 g/mol × 10) + (1.01 g/mol × 8) = 128.19 g/mol

Step 2: Calculate the moles of naphthalene.

To convert the given mass of naphthalene to moles, divide the mass by the molar mass:

Moles of naphthalene = 14.5 g / 128.19 g/mol = 0.113 moles

Step 3: Calculate the heat of combustion per mole of naphthalene.

Divide the heat evolved by the moles of naphthalene to determine the heat of combustion per mole of naphthalene:

Heat of combustion per mole of naphthalene = 583 kJ / 0.113 moles = 5168.14 kJ/mol

Therefore, the heat of combustion of naphthalene is 5168.14 kJ/mol when 14.5 g of naphthalene is combusted.