The change in internal energy for the combustion of 1.0 mol of octane at a pressure of 1.0 atm is -5084.1 kJ. You may want to reference (Pages 381 - 385) Section 9.6 while completing this problem.

This is an incomplete question, here is a complete question.

The change in internal energy for the combustion of 1.0 mol of octane at a pressure of 1.0 atm is -5084.1 kJ. You may want to reference (Pages 381 - 385) Section 9.6 while completing this problem. If the change in enthalpy is -5074.2 kJ, how much work is done during the combustion? Express the work in kilojoules to three significant figures.

Answer : The work done during the combustion is, 9.9 kJ

Explanation :

Formula used :

where,

w = work done = ?

= change in enthalpy  = -5074.2 kJ

= change in internal energy  = -5084.1 kJ

R = gas constant = 8.314 J/mol.K

Now put all the given values in the above formula, we get:

Thus, the work done during the combustion is, 9.9 kJ

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current