propane is combined with 50% excess air in a mixer before being fed to a furnace. The propane (C3H5) enter the mixer at 25 degrees celsius at a rate of 300Kg/h and the air enters the mixer at 500 degrees celsius. Heat is lost form the mixer to the surroundeings at a rate of 8.5KW. Given MW(propane= 4.4; Cp(Propane)=0.068032KJ/mol. degrees celsius; Cp(air) =0.0289KJ/mol degrees celsius. Use table 8 for calculation.  a. Calculate the molar flow of air that enters the mixer.

Saturated ammonia vapor at 25°C condenses on the outside surface of 16 thin-walled tubes, 2.5 cm in diameter, arranged horizontally in a 4 × 4 square array. Cooling water enters the tubes at 14°C at an average velocity of 2 m/s and exits at 17°C. Calculate (a) the rate of NH3 condensation, (b) the overall heat transfer coefficient, and (c) the tube length.  

Insulated Sample Burning outside dish sample chamber Steel bomb Combustion (bomb) calorimeter. In an experiment, a 0.6629 g sample of phthalic acid ( C8H604) is burned completely in a bomb calorimeter. The calorimeter is surrounded by 1.046 x 10³ g of water. During the combustion the temperature increases from 24.04 to 26.63 °C. The heat capacity of water is 4.184 J-g¹. C-¹. The heat capacity of the calorimeter was determined in a previous experiment to be 788.9 J. ˚C-¹. Assuming that no energy is lost to the surroundings, calculate the molar heat of combustion of phthalic acid based on these data. C8 H6 O4(s) + (15/2) O2(g) → 3H₂O(l) + 8CO2 (g) + Energy kJ/mol Molar Heat of Combustion =

Heating Air by Condensing Steam. Air is flowing through a tube having an inside di- ameter of 38.1 mm at a velocity of 6.71 m/s, average temperature of 449.9 K, and pres- sure of 138 kPa. The inside wall temperature is held constant at 204.4°C (477.6 steam condensing outside the tube wall. Calculate the heat-transfer coefficient for a long tube and the heat-transfer flux. K) by Ans. h = 39.38 W/m² K (6.94 btu/h. ft².°F)