Question

A certain mass of gas occupied 850ml at pressure of 760 mm of Hg. On increasing the pressure it was found that the volume of the gas was 75% of its initial volume.Assuming constant temperature find the final pressure of the gas ?

Answer 1

we know that for an ideal gaspv=nrtand hence v=nrt/pin the question it is given that the same gas is kept afterwards at a lower pressure and hence the no. of moles is same so we know that the value of n,r,t are same (r is gas constant)so v \propto 1/pwe also knoe that the final volume of gas is 75% of initial volume=850*75/100 mlso volume initially(L)/volume final(L) =pressure final(atm) /pressure innitially(atm)so(850/1000) / (850*75/(100*1000))= (760/760) /p_{f}so p_{f} =0.75 atmwhich equals 570mm of hgi hope this helps if so plz approve this ans