An ideal vapor compression refrigeration cycle with R134a as the working fluid operates between the pressure limits of 200 kPa and 1200 kPa. Determine

a) the mass fraction of the refrigerant that is in the liquid phase at the inlet of the evaporator, and

b) the amount of heat transfer (in kJ/kg) to the refrigerant in the evaporator (??).

15 m3 /min of air at 104o F and 60% relative humidity is cooled to 59o F and 100% relative humidity, and then reheated to 68o F. Find the following:

a. The flow rate of dry air (BDA) in kg /min.

b. The amount of water condensed during cooling stage.

c. kW of power needed for cooling the air in the cooling stage.

d. kW of power needed for the heating step.

Calculate the fugacity of liquid water in a binary liquid mixture with 40 mole % water and 60 mole % ethanol at 70°C. The following activity coefficient data, at infinite dilution, are available: yinfinite H2O. = 2.62 and yinfinite ethanol = 7.24

what features would you expect to find at a convergent plate boundary? Be specific and discuss earthquakes, the age of the ocean floor, volcanoes, and topographic features. describe any convergent boundaries present on the west coast of north america.

Please write a full page describing this

If it is a hot day and the swamp cooler isn't working, if one were to open their refrigerator door to cool the house down, would it work? Please give an explanation that pertains to thermodynamics.

In hot and humid areas, swamp coolers don’t work. Those places use heat pumps and dump the heat into pipes that are buried in the ground. Underground, the temperature is considered constant all year, assume 55 °F. What will be the improvement in terms of energy efficiency with this arrangement, as opposed to using a conventional air conditioner? Assume the house is to be maintained at 70 °F and the outside temperature is 95 °F. Calculate the energy required per BTU of heat removed from the house, for these two arrangements, heat pump versus air conditioner.

Please show your work. Thank you so much !

Bismuth and cadmium form a simple eutectic mixture that behaves like that in model 3. Bismuth melts at 271°C and 1 bar, whereas cadmium melts at 321°C and 1 bar. The enthalpy of fusion of bismuth is 11.30 kJ/mol, and that of cadmium is 6.19 kJ/mol. A eutectic point is observed at 55.5 mol% cadmium.

1. Calculate the melting temperature of the eutectic mixture. Assume ideal behavior. 

2. Roughly sketch the phase diagram at 1 bar, labeling the points described above for reference. 

3. Sketch a cooling curve that passes through the eutectic point. 


Water flowing at a rate of 0.03 kg/s is heated from 20 to 40°C in a horizontal pipe (inside diameter = 3 cm). The inside pipe surface temperature is 70°C. Estimate the convective heat transfer coefficient if the pipe is 1 m long. Assume forced convection conditions.  Ts is not held constant!

Properties of Water

An outside-air sample is taken on a day when the temperature is 78 F and the relative humidity is 40%.

(a) Use the psychrometric chart to state as many physical properties of the air as you can without doing any calculations. For each one, provide a brief description of the property listed.

(b) A thermometer is mounted on the back porch of your house. What temperature would it read for the air described in this problem?

(c) A sample of outside air is cooled at constant pressure. At what temperature would condensation begin?

(d) You step out of your neighborhood pool and feel quite cold until you dry off. Explain why. Estimate your skin temperature while you were still wet. Explain your answer. What would be different if the relative humidity were 98%?

4. The next question has to do with the condensation of water a. When water condenses on your glass, does it cool or warm the drink? b. If a can of soda at 1.0 °C has 6.512 grams of water condense on the outside, how much energy was transferred? The heat of condensation of water is 2.26kJ/g. c. If all the energy came from the soda, and the soda has the same heat capacity as water, what is the final temperature of the soda in °F?

5. A 5.69 g sample of copper metal was heated in boiling water to 99.8°C. Then it was dropped into a beaker containing 100.0 g of H2O at 22.6°C. Assuming the water gained all the heat lost by the copper, what is the final temperature of the H2O and Cu? The specific heat of water is CP=4.184 J/g∙°C and the specific heat of copper is CP,Cu=0.386 J/g∙°C

Methanol is synthesized by the gas phase reaction: Stoichiometric amounts of CO and H2 are mixed in an evacuated vessel (i.e. no methanol is present initially), and the reaction is allowed to come to equilibrium. Calculate the equilibrium mole fraction of methanol under the following conditions.

CO+2H₂-> CH₃OH

(c) The equilibrium temperature and pressure are 365 K and 1 atm, the mixture behaves as an ideal gas and a more accurate description of the temperature dependence of the equilibrium constant is available where T is in K. ln K = 21.8158+9,052/(T)-7.663ln(T)+5.4075x10-3 (T)-5.75x10-7 (T2 )-6.75x103 /(T2 )

Consider the daytime production of nitric acid from the reaction of OH^. radical and NO₂ in the gas phase. The chemistry is given below with a rate coefficient of 16 ppbV^-1 min^-1.

OH^. + NO₂ -> HNO₃

During the daytime, OH^. concentration is 4x10^-4 ppbV. If we start with 50 ppbV of nitrogen dioxide and nitrogen dioxide does not get replenished, how much nitric acid has been formed after one hour?