[mongducanh5893]

Ex1 :A system undergoes a process consisting og the following two steps
Step 1: The system absorbs 72J of heat while 35J of work is done on it
Step 2: The system absorbs 35 J of het while performing 72 J of work
Calculate the ΔE for the overall process.
Ex 2: A sample of an ideal gas at 15 atm and 10 L is allowed to expand against a constant external pressure of 2 atm at a constant temperature. calculate the work in units of kJ for the gas expansion. ( Hint: using Boyle's lawapplies)
Thanks you very much

[Jorriss]

Have you given these any thought?

[Darren]

ΔU=Q+W, where delta U is the change in internal energy of the system, Q is the heat supplied TO the system, and W is the work done ON the system. Fit in the values you've got and you get the change in internal energy of the system.

For the second question, use P₁V₁=P₂V₂ to find the final volume of the gas at equilibrium.