Turn on thread page Beta
    • Thread Starter
    Offline

    2
    ReputationRep:
    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
    Offline

    0
    ReputationRep:
    (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.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 13, 2013
The home of Results and Clearing

2,743

people online now

1,567,000

students helped last year

University open days

  1. SAE Institute
    Animation, Audio, Film, Games, Music, Business, Web Further education
    Thu, 16 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Fri, 17 Aug '18
  3. University of Bolton
    Undergraduate Open Day Undergraduate
    Fri, 17 Aug '18
Poll
Do you want your parents to be with you when you collect your A-level results?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.