- #1
elly92
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Homework Statement
Hi, I have this coursework due in 2 days and I have no clue how to start it! Please Help any hints will be very nice. I tried attempting it several times but I can't understand it the question properly! My Thermo lecturer isn't making the subject clear and I have no clue how to approach the question.
Q1. A vessel with volume 5m3 contains 0.05m3 of saturated liquid water and
4.95m3 of saturated water vapour at 0.1MPa. Heat is transferred until the
vessel is filled with saturated vapour. Determine the heat transfer for this
process
Q2. A cylinder fitted with a piston has an initial volume of 0.1m3 and contains
nitrogen at 150kPa, 25oC . The piston is moved, compressing the nitrogen
until the pressure is 1MPa and the temperature is 150oC . During this
compression process, heat is transferred from the nitrogen, and the work done
on the nitrogen is 20kJ. Determine the amount of this heat transfer. For the
nitrogen, you may assume that
c(p) = 1110 = 480(T/1000) + 960(T/1000)^2 -420(T/1000)^3
where T is measured in K, and C(p) is measured in J/KgK
Q3. A mass of a liquid, m, at temperature, T1, is mixed with an equal mass of the
same liquid at temperature, T2. The system is thermally insulated. Show that
the change of entropy of the Universe is:
2mc(p)ln[ ({T(1) + T(2)}/2)/[(Square root)T1*T2]]
and prove that this is necessarily positive.
[Do not specifically consider the mixing of the fluids.].
Thanks in advance!