Calculate the heat of formation of butane given that the heat of formation of H20(l) is -285.3 kj/mol and the heat of formation of CO2(g) is -393.5 kj/mol.
Balance this equation
butane+O2 >> CO2 + H2O
Then, apply Hess' Law.
I will be happy to critique your thinking.
Thank you. there is also a second part.
B.) assuming that all the heat evolved in burning 30 g of butane is transferred to 8 kg of water at 22.2 degrees celsius (specific heat=4.184 J/gxK), calculate the final temperature of the water.
To calculate the heat of formation of butane (C4H10), you need to use the concept of Hess's Law and knowledge of the heat of formation of other compounds involved.
Hess's Law states that the total enthalpy change for a reaction is independent of the pathway between the initial and final states. In other words, the overall change in enthalpy is the same regardless of how the reaction occurs.
Here's how you can calculate the heat of formation of butane (C4H10) using Hess's Law:
1. Write the balanced equation for the combustion of butane (C4H10):
C4H10(g) + 13/2 O2(g) → 4CO2(g) + 5H2O(l)
2. Identify the known heats of formation:
Heat of formation of H2O(l) = -285.3 kJ/mol
Heat of formation of CO2(g) = -393.5 kJ/mol
3. Determine the heat of formation of butane from the known heats of formation:
Heat of formation of butane (C4H10) = [Heat of formation of 4CO2(g) + 5H2O(l)] - [Heat of formation of C4H10(g) + 13/2 O2(g)]
4. Substitute the values:
Heat of formation of butane (C4H10) = [(4 x -393.5 kJ/mol) + (5 x -285.3 kJ/mol)] - [x + (13/2 x 0 kJ/mol)]
5. Solve for x (heat of formation of C4H10):
Heat of formation of butane (C4H10) = (-1574 kJ/mol - 1426.5 kJ/mol) - x
6. Simplify the equation:
Heat of formation of butane (C4H10) = -3000.5 kJ/mol - x
Therefore, to calculate the heat of formation of butane, you need the value of x. Unfortunately, the information provided does not include the heat of formation of C4H10 (butane). Without that value, it is not possible to calculate the heat of formation of butane in this scenario.