A sample of 260.0 of liquid water is initially at a temperature of 75.0ºC. If that water is heated by the combustion of 26.00 grams of coal (carbon) to form carbon dioxide. Assume all the heat from combustion goes into the water. Determine the final state and temperature of the H2O. Explain the determination of the energy produced by combustion of the coal, the amount of energy used to heat the liquid water, the energy needed to vaporize the liquid water, and the final temperature determination.

The heat of vaporization of a liquid (AHp) is the energy required to vaporize 1.00 g of the liquid at its boiling point. In one experiment, 80.0 g of liquid nitrogen (boiling point = -196.0 °C) are poured into a Styrofoam cup containing 2.00 x 10² g of water at 60.0 °C. Calculate the molar heat of vaporization of liquid nitrogen if the final temperature of the water is 41.0 °C. The heat capacity of water is 4.18- J Be sure your answer has the correct number of g "C significant digits. Note: Reference the SI prefixes table for additional information. kJ mol

21. A large containment is filled with steam, air, and nitrogen. The containment also has a pool of water, which is sprayed in the containment atmosphere. Heat is added to the con- tainment at a specified rate. Use the given data to find a) the initial containment pressure and b) the time it takes for the containment pressure to reach the pressure limit of 145 psia (1 MPa). Total mass of water (water in the pool and steam) m,, = 3.42E6 lbm (1.55E6 kg) Water-steam quality x = 0.03 Air mass m, = 0.132E6 lbm (6E4 kg) Nitrogen mass m, = 2200 lbm (998 kg) Containment initial temperature T; = 688 R (109 C) Initial relative humidity ø = 100% Rate of heat addition to containment atmosphere Q = 1.02E8 Btu/h (30 MW) [Ans.: 7.66 h].

The fuel in the form of biogas (65%-mol CH4 and 35%-mol CO2) is burned in a furnace. In order for combustion to take place stoichiometrically, calculate the air to fuel ratio (vol/vol) from this problem!