Common mistakes on HW7

Hi class,

Here are some common mistakes that were made on HW7. Please check to see if you made these so as to avoid them in the future.

Problem 32: "well-insulated" implies "adiabatic" - which means Q = 0, not necessarily that delta(T) = 0 (although with an ideal gas in a process that also does no work, delta(T) will equal zero).

Problem 33: need to use absolute temperatures with the efficiency, Qc, and Qh equations.

Problem 34: need to use consistent units with the Q=n*cp*delta(T) equation

Problem 38: constants in table c.1 have units (e.g. B has units of 1/Kelvin and C has units of 1/Kelvin^2); basically another reminder to take care with units and make sure that they match up.

Cheers,
MSS