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 à 10) + (1.01 g/mol à 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.