A 4- m3 uninsulated storage tank, initially evacuated, is connected to a line flowing ethane gas at 10 MPa, 100C. The valve is opened, and ethane flows into the tank for a period of time, after which the valve is closed. Eventually, the whole system cools to ambient temperature, 0C, at which time the it contains one-fourth liquid and three-fourths vapor, by volume. For the overall process, calculate the heat transfer from the tank and the net change of entropy.