The enthalpy of cimbustion for Octane vapor, C8H18, a component of gasoline, is -5512.0kJ/mol.
a. Write the equation for the combustion of Octane, including the energy term.
b. Calculate the energy change when 45g of Octane burn.
c. Calculate the energy produced when 45g of Octane burn.
a. To write the equation for the combustion of Octane, we need to know the reactants and products involved in the reaction. The reactant is Octane (C8H18), and the products are carbon dioxide (CO2) and water (H2O). The balanced equation is:
C8H18 + 12.5O2 -> 8CO2 + 9H2O
The energy term for the combustion of Octane can be represented as:
C8H18 + 12.5O2 -> 8CO2 + 9H2O + heat
b. To calculate the energy change when 45g of Octane burns, we need to use the molar mass of Octane (C8H18) and then convert the grams to moles.
1. Calculate the molar mass of Octane:
C: 12.01 g/mol
H: 1.008 g/mol
Octane (C8H18): (8 * 12.01 g/mol) + (18 * 1.008 g/mol) = 114.23 g/mol
2. Convert grams of Octane to moles:
45 g Octane * (1 mol/114.23 g) = 0.394 moles
3. Multiply the moles of Octane by the enthalpy change per mole (-5512.0 kJ/mol):
0.394 moles * (-5512.0 kJ/mol) = -2171.85 kJ
Therefore, the energy change when 45g of Octane burns is -2171.85 kJ.
c. To calculate the energy produced when 45g of Octane burns, we can use the fact that energy change is equal to the amount of energy produced.
Since we calculated in part b that the energy change is -2171.85 kJ, we can conclude that when 45g of Octane burns, -2171.85 kJ of energy is produced.