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Chem Problem I don't get

  1. Oct 23, 2005 #1
    Suppose you want to heat the air in your house with natural gas (CH_4). Assume your house has 275 m^2 of floor are and ceilings are 2.5 m from floors. The air in your house has a specific heat capacity of 29.1 J/mol K. The number of moles in the house can be found by assuming the molar mass of air is 28.9 g/mol and that the density of the air at these temperatures is about 1.22 g/L. How much grams methane do you have to burn to heat air from 15.0 to 22.0 C?

    So, here is how I think I can solve it.
    1. Determine number of moles of air. I have no idea how to do that.
    2. specific heat*temp*moles of CH4 = specific heat*temp*moles of water.

    But I can't! Any help, please?
  2. jcsd
  3. Oct 23, 2005 #2


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    For (1) you have been given all the information except volume conversion
    1 cubic meter = 1000L
  4. Oct 23, 2005 #3
    For air, I got:
    Change in temp: 7.0 C
    specific heat: 29.1 J/molK
    mass= 839*10^5 g (should I convert this into moles?)
    For methane:
    specific heat: 4.18 j/molK
    I need to solve for mass, right?
    But I don't have temperature change in methane?

    HELP! please,:smile: ?
  5. Oct 23, 2005 #4


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    Well for one... how do you heat a house with methane without combustion????

    You're missing a piece of information
  6. Oct 24, 2005 #5


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    why water?

    First, how would you find the heat energy given off by the combustion of methane?
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