Heat capacity of air can be approximately expressed as, Cp = 26.693 + 7.365 x10-3 T, where, Cp is in J/mole.K and T is in K. The heat given off by 1 mole of air when cooled at atmospheric pressure from 500°C to – 100°C is ____________________?

Related Mcqs:

1. What is the total pressure exerted by a mixture of 0.45 kg mole of benzene, 0.44 kg mole of toluene and 0.23 kg mole of o-xylene at 100°C, if their vapor pressures at 100°C are 1340, 560 and 210 mmHg respectively ?

   A. 756.2
   B. 780.5
   C. 801.5
   D. 880.5

2. At 100°C, water and methylcyclohexane both have vapour pressures of 1 atm. Also at 100°C, the latent heats of vaporisation of these compounds are 40.63 kJ/mole for water and 31.55 kJ/mole for methylcyclohexane. The vapour pressure of water at 150°C is 4.69 atm. At 150°C, the vapour pressure of methylcyclohexane would be expected to be_________________?

   A. Significantly less than 4.69 atm
   B. Nearly equal to 4.69 atm
   C. Significantly more than 4.69 atm
   D. Indeterminate due to lack of data

3. A car tyre of volume 0.057 m3 is inflated to 300 kPa at 300 K. After the car is driven for 10 hours, the pressure in the tyre increases to 330 kPa. Assume air is an ideal gas and Cv for air is 21 J/mole.K. The change in the internal energy of air in the tyre in J/mole is__________________?

   A. 380
   B. 630
   C. 760
   D. 880

4. The accumulation in a steady state combustion process, burning 1 kg mole of carbon with 1 kg mole of oxygen thereby producing 1 kg mole of carbon dioxide, is _____________ kg mole?

   A. 1
   B. 0
   C. 16
   D. 44

5. A very dilute solution is prepared by dissolving ‘x1’ mole of solute in ‘x2’ mole of a solvent. The mole fraction of solute is approximately equal to_________________?

   A. x1/x2
   B. x2/x1
   C. 1 – (x1/x2)
   D. 1/x2

6. A rigid vessel containing three moles of nitrogen gas at 30°C is heated to 250°C. Assume the average capacities of nitrogen to be Cp = 29.1 J/mole.°C and, Cv = 20.8 J/mole.°C. The heat required, neglecting the heat capacity of the vessel, is__________________?

   A. 13728 J
   B. 19206 J
   C. 4576 J
   D. 12712 J

7. At standard conditions, N2 + 2O2 ⇌ 2NO2; ΔG° = 100 kJ/mole NO + ½O2 ⇌ 2NO2; ΔG° = -35 kJ/mole The standard free energy of formation of NO in kJ/mole is___________________?

   A. 15
   B. 30
   C. 85
   D. 170

8. Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 KPa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mole/m3. The diffusivity of aniline in air is 0.74 × 10-5m2/s. The numerical value of mass transfer co-efficient is 7.4 × 10-3. Its units are_______________________?

   A. m/s
   B. cm/s
   C. mole/m2.s.Pa
   D. k.mole/m2.s.Pa

9. The combustion equations of carbon and carbon monoxide are as follows: C + O2 = CO2, ΔH = – 394 kJ/kg .mole CO + ½ O2 = CO2, ΔH = – 284.5 kJ/kg. mole. The heat of formation of CO is _____________ kJ/kg. mole?

   A. -109.5
   B. +109.5
   C. +180
   D. +100

10. One mole of methane undergoes complete combustion in a stoichiometric amount of air. The reaction proceeds as CH4 + 2O2 → CO2 + 2H2O. Both the reactants and products are in gas phase. ΔH°298 = – 730 kJ/mole of methane. Mole fraction of water vapour in the product gases is about_____________________?

    A. 0.19
    B. 0.33
    C. 0.40
    D. 0.67