Question

4g of oxygen gas initially at STP is adiabatically compressed to a third of its original volume,find the values of,the pressure and temperature

Answer 1

Answer:

Solution



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Volume of oxygen, V1= 30 litres =30×10−3m3 

Gauge pressure, P1= 15 atm =15×1.013×105Pa

Temperature, T1=27oC=300K

Universal gas constant, R=8.314Jmol−1K−1

Let the initial number of moles of oxygen gas in the cylinder be n1 .

The gas equation is given as:

P1V1=n1RT1

∴n1=P1V1/RT1

=(15.195×105×30×10−3)/(8.314×300)=18.276

But n1=m1/M

Where, 

m1= Initial mass of oxygen 

M = Molecular mass of oxygen = 32 g

∴m1=N1M=18.276×32=584.84g

After some oxygen is withdrawn from the cylinder, the pressure and temperature reduces.

Volume, V2= 30 litres =30×10−3m3 

Gauge pressure, P2