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    Hello, can anybody help me with the following please?
    A flask of volume 9.0x10-4 m^3 contains air. A vacuum pump reduces the pressure in the flask to 150Pa at temperature 30K. For the air remaining in the flask calculate:
    Its density
    the number of molecules present, assuming the molar mass of air is 0.029Kg/mol
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    (Original post by stanners 27)
    Hello, can anybody help me with the following please?
    A flask of volume 9.0x10-4 m^3 contains air. A vacuum pump reduces the pressure in the flask to 150Pa at temperature 30K. For the air remaining in the flask calculate:
    Its density
    the number of molecules present, assuming the molar mass of air is 0.029Kg/mol
    To find the density, you'll need the mass and the volume because density = mass/volume. You have the volume but not the mass. You'll need to find the mass using the equation pV=nRT. Substitute your values of p, V, T and R (which is 8.31) and you'll get n.
    n = Mass/Molar mass
    Mass = n x Molar mass.
    This way you have a mass and a volume.
 
 
 
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