posted by .

Outside air generally contains some water vapor (typically 1-2% by mass). Does it take more, less, or the same heat to raise the temperature of 1kg moist air than is needed to raise the temperature of 1kg dry air by the same amount?

  • physics -

    Since the molecular weight of water vapor is 18 and that of air is 29 (the N2/O2 weighted average), the presence of H2O vapor therefor lowers the average molecular weight of air. 1 kg of dry air will have fewer moles than 1 kg of moist air.

    It will take more energy to heat the gas with more moles (moist air)

    Water vapor has a higher molar specific heat (than O2 and N2) as well, but the fact that there will be more moles in the same mass of moist air is what makes the biggest difference

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. vapor pressure

    The total pressure in a flask containing air and ethanol at 25.7C is 878 mm Hg. The pressure of the air in the flask at 25.7C is 762 mm Hg. If the flask is immersed in a water bath at 450C, the total pressure is 980 mm Hg. The vapor …
  2. chem - dry ice activity

    does the dry ice disappear more quickly in air or in water?
  3. ecology

    An air conditioner lowers the temperature of the surrounding air. water condensed from the air is most likely to run out of the bottom water hose of a automobile air condition when the air entering the air conditioner. a- contains …
  4. Physics - calorie

    This was my problem: 4.) The specific heat capacity of copper is 0.092 cal/g*oC. Show that the amount of heat needed to raise the temperature of a 10-g piece of copper from 0oC to 100oC is 92 cal. How does this compare with the heat …
  5. Physics

    How long would it take a kettle with a 1kW heating element to heat 1 litre of water?
  6. Physical Chemistry

    A mole of air (80% Nitrogen, and 20% Oxygen by volume) at 298.15K is brought into contact with liquid water which has a vapor pressure of 3168Pa at this temperature. a) what is the volume of the dry air if the pressure is 1 bar?
  7. Chemistry

    On a warm summer day in Athens, the temperature is 33C (dry bulb temperature) and the relative humidity is 60%. What is the absolute humidity?
  8. physics

    A copper container of mass 100g contains 500g of water. A steel paddle of mass 85g stirs the water. A pulley system operates the paddle. A) the mass (15kg) drops 2,4m, turning the steel paddle. Assume heat lost to surrounding is negligible. …
  9. physics

    Before leaving for a vacation£¬the owners of a home 8.0m *21m*5.0m turn the thermostat down to 14celcius. On their return£¬how much heat is needed to raise the temperature of the air inside the home to 21celcius£¿Ignore the heat …
  10. Chemistry

    Compare the energy needed to raise the temperature of 1kg of water from 20°C to 100°C and the energy needed to boil 1kg of water at 100°C?

More Similar Questions