You need a steam table to solve Q1 and Q2

Using Q1 as an example to guide you how to solve these 2 problems:

To find the mass of the system, you need an isobaric table (at 4 Bar) which shows how the density changes with temperature. You can generate the required steam table at the NIST Web Book. By establishing the density of steam at 4 bar 200C, you can find the mass by multiplying the volume by its density. Take note of its internal energy at that this state. Call this U

_{1} (unit kJ).

The state whereby vapour and liquid phases co-exist must be that at the saturated temperature and pressure. To find the required phase composition, you need the table that shows the saturated properties of water and steam. You can generate this table again at the NIST Web Book. The saturated temperature at 3.9549 bar is 143.20C. The saturated temperature at 4.1113 bar is 144.60C. I am sure you can extract the saturated temperature at 4 bar from this data set by assuming the saturated temperature varies linearly with pressure.

Apply the same method to extract the specific volume (inverse of density) for saturated liquid and vapour phases at 4 bar. Do a mass balance between the 2 phases to establish the vapour and liquid fractions. Sum up the internal energy contributions from the liquid and vapour phases to get the internal energy of this state. Call this U

_{2} (unit kJ).

To find work done (W) and heat transfer (Q)

use dU = Q + W where dU = U

_{2} - U

_{1} (applicable to close system)

Since this is a close system, W = - p.dV = - (4E5)(0.1-0.5) = 160 kJ

Q = dU - W = U

_{2} - U

_{1} - 160 (Unit kJ)

To solve Q2, please go to the NIST Web Book to get your relevant data

**yourself** and solve Q2

**on your own**The NIST Web Book Address for obtaining fluid properties is:

http://webbook.nist.gov/chemistry/fluid/