--%>
Assignment Help - homework help

Problem on heat of sublimation

Using the vapor pressure data provided below, estimate

i) the heat of sublimation of ice,

ii) the heat of vaporization of water,

iii) the heat of fusion of ice and compare your estimate with the published value of 6010 J/moL

iv) the triple point of water (pressure and temperature). Solve the nonlinear.

                                           T(°C)                             Vapor Pressure (mm Hg)
Ice                                       -4                                            3.280
                                            -2                                            3.880
Water                                   +2                                            5.294
                                            +4                                            6.101

E

Expert

Verified

At 1 atm pressure, ice melts at 0°C

density of ice = 920 kg/m3
density of liquid water = 997 kg/m3

Now using the Clapeyron equation

dP/dT = LP/RT2  [ where Vg>>>Vl]

On integration:

Ln[P1/P2] = -L/R[ 1/T1 -1/T2]

Ln(3.880/3.280)= -L/R [ 1/271-1/269]

So Ice  L = ΔH sublimation = - 50911.5 J/mol =-50.9115KJ/mole

Similarly for water L = ΔH vap =- 44929.9 J/Mole =- 44.929 KJ/mole

Now At triple point Ice /Water /Saturate water Vap co-exists Now using the Thermo concept at triple point 

ΔH sublimation = ΔH vap + ?H fusion

Similarly  at triple vap pressure of water = vap pressure of ice

LnP = ln(3.880)-50911.5/8.3145[1/T – 1/271] = ln(5.294)-44929.9/8.3145[1/T-1/275]

So Solving for T we get T =273.1297K

Now Solving for P we get

LnP = ln(3.880)-50911.5/8.3145[1/273.129 – 1/271]
LnP = 1.532014

So P = 3.589546 mmHg

   Related Questions in Chemical Engineering

  • Q : Hh to determine the temperature that

    to determine the temperature that occurred in a fire in a warehouse, the arson investigator noticed that the relief valve on a methane storage tank had popped open at 3000 psig, the rated value. Before the fire started, the tank was presumably at ambient conditions and the gage read 1950 psig. If th

    		•
  • Q : Problem on laboratory solution You are

    You are asked to make up a laboratory solution of 0.10 molar H2SO4 from concentrated (96%) H2SO4 at 56°F. The barometric pressure reads 750 mmHg. You look up the specific gravity of 96% H2SO4 and find it is listed at 1.858. Calculate: (a) th

    		•
  • Q : Mass transfer adsorption how to

    how to calculate amount of ammonia adsorbed per kg of adsobent in ammonia calcium chloride adsorption process?

    		•
  • Q : Problem on ideal gas law A stream of

    A stream of steam at 1 bar and 400 K enters a compressor through a pipe with cross-sectional area of 0.1 m2 at a velocity of 5 m/s. The pressure of the outlet stream is at 5 bar, temperature is at 500 K, and velocity is 1 m/s. Assume the steam can be descri

    		•
  • Q : Problem on steam flow in a pipe A

    A stream of steam at 15 bar and 300 oC is used to produce work using a steam turbine. a. Before the turbine, steam flows in a pipe (4 cm in diameter) at a mass flow rate of 3 g/s. Calculate the mean velocity in the pipe

    		•
  • Q : Calculating flow rate of nitrogen The

    The feed of an ammonia synthesis reactor is 25% (lbmole) nitrogen with the balance hydrogen. The flow rate is 3000 kg/h at 65°C and 95 bar. Calculate the flow rate of nitrogen to the reactor in kg/hr.

    		•
  • Q : Thermodynamics I) Sulphur dioxide (SO2)

    I) Sulphur dioxide (SO2) with a volumetric flow rate 5000cm3/s at 1 bar and 1000C is mixed with a second SO2 stream flowing at 2500cm3/s at 2 bar and 200C. The process occurs at steady state. You may assume ideal gas behaviour. For SO2 take the heat capacity at constant pressure to be CP/R = 3.267+5

    		•
  • Q : Problem on empirical van Laar equation

    At atmospheric pressure ethyl acetate and ethyl alcohol form an azeotropic mixture containing 53.9% mole of ethyl acetate and boiling at 71.8°C. a) Estimate the values of A & B in the empirical van Laar equation

    		•
  • Q : Problem on heat required for process A

    A steady-state flow process is used to heat methanol in a tank. The incoming stream is at 2 bar and 25 oC and has a flow rate of 5 kg/s. The outgoing stream is at 1 bar, 100 oC. Heating is provided by a heating coil immersed in a tank. Given the

    		•
  • Q : Materials and energy balance you look

    you look up the specific gravity of 96% H2SO4 and find it is 1.858.calculate the weight

    		•