Octane (C8H18) is the main hydrocarbon in gasoline. Using bond energies, calculate the amount of energy produced from 2.5 kilograms of octane.
I know how to do bond energies, but
If someone could tell me what to do with the 2.5 kg in this case and possibly tell me what answer i should get so i can work it out that would be great!
Thanks
You calculate the energy per mole octane from the balanced equation, then multiply that energy x (2,500g/molar mass octane) = ??
To calculate the amount of energy produced from 2.5 kilograms of octane using bond energies, you'll need to follow these steps:
1. Determine the molar mass of octane (C8H18). The molar mass of carbon (C) is approximately 12.01 g/mol, and the molar mass of hydrogen (H) is approximately 1.01 g/mol. Hence, the molar mass of octane is:
(8 x 12.01 g/mol) + (18 x 1.01 g/mol) = 114.23 g/mol
2. Convert the mass of octane to moles. Since the molar mass of octane is 114.23 g/mol, you can use the following equation:
Moles = Mass / Molar mass
Moles = 2.5 kg * (1000 g/kg) / 114.23 g/mol
3. Calculate the energy produced from the combustion of one mole of octane. To do this, you'll need the bond energies of the bonds broken and formed in the combustion reaction. The balanced combustion reaction for octane is:
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
4. Determine the bond energies for the relevant bonds broken and formed in the reaction. Here are some bond energies you can use (in kilojoules per mole):
C-C: 348 kJ/mol
C-H: 413 kJ/mol
C=O: 799 kJ/mol
O=O: 498 kJ/mol
O-H: 464 kJ/mol
5. Calculate the total energy produced from the combustion of the moles of octane. Use the bond energies in the combustion reaction equation to calculate the energy released for each bond broken and formed, and then calculate the net energy released.
Remember to account for the stoichiometric coefficients in the balanced reaction. The total energy produced will be in kilojoules (kJ).
To calculate the amount of energy produced from 2.5 kilograms (kg) of octane (C8H18) using bond energies, you will need to do the following steps:
Step 1: Determine the molar mass of octane.
Octane (C8H18) has a molar mass of 114.22 grams per mole (g/mol). You can calculate this by adding up the atomic masses of the constituent atoms (carbon and hydrogen) in one molecule of octane.
Step 2: Convert kilograms to grams.
Since the given quantity is in kilograms, convert it to grams. There are 1000 grams in one kilogram. Therefore, 2.5 kg is equivalent to 2.5 × 1000 = 2500 grams (g).
Step 3: Calculate the number of moles of octane.
To find the number of moles, divide the mass of octane by the molar mass:
Number of moles = mass of octane (in grams) / molar mass of octane (in g/mol).
Number of moles = 2500 g / 114.22 g/mol.
Step 4: Calculate the energy produced.
Use the given bond energies of carbon-hydrogen (C-H) and carbon-carbon (C-C) bonds:
The bond energy of C-H is approximately 413 kilojoules per mole (kJ/mol).
The bond energy of C-C is approximately 348 kilojoules per mole (kJ/mol).
Multiply the number of moles by the number of C-H bonds and the number of C-C bonds in octane, and then multiply by the corresponding bond energies to calculate the total energy produced.
Finally, divide by 1000 to convert kilojoules to joules, because bond energies are usually given in kJ/mol.
The resulting final answer will be in joules (J).
Please note that the calculated energy value will be an approximation because bond energies can vary depending on the specific environment and other factors.
I hope this helps!