Calculate the heat generated by the complete combustion of 15.0g of ethane.
To calculate the heat generated by the complete combustion of ethane, we need to determine the heat of combustion of ethane and the molar mass of ethane.
1. Find the molar mass of ethane (C2H6):
- The molar mass of carbon (C) is approximately 12.01 g/mol.
- The molar mass of hydrogen (H) is approximately 1.01 g/mol.
- Ethane (C2H6) has 2 carbon atoms and 6 hydrogen atoms.
Molar mass of ethane (C2H6) = (2 × molar mass of carbon) + (6 × molar mass of hydrogen)
Molar mass of ethane (C2H6) = (2 × 12.01 g/mol) + (6 × 1.01 g/mol)
Molar mass of ethane (C2H6) ≈ 30.07 g/mol
2. Calculate the moles of ethane from the given mass:
Moles of ethane = Mass of ethane / Molar mass of ethane
Moles of ethane = 15.0 g / 30.07 g/mol
Moles of ethane ≈ 0.498 mol
3. Determine the heat of combustion of ethane:
The standard heat of combustion of ethane is -1560 kJ/mol. This value indicates the amount of heat released per mole of ethane completely combusted.
4. Calculate the heat generated:
Heat generated = Moles of ethane × Heat of combustion of ethane
Heat generated = 0.498 mol × (-1560 kJ/mol)
Heat generated ≈ -775.68 kJ
The heat generated by the complete combustion of 15.0g of ethane is approximately -775.68 kJ (negative sign indicates the release of heat).