Asample of gas at 25ºc has a volume of 11 l and exerts a pressure of 660 mm hg. how many moles of gas are in the sample?

  The  moles of  the gas    in the sample  is 0.391  moles

    calculation
by use  of  ideal  gas  equation, that  is Pv=nRT
where  n  is number  of moles
           P(pressure)= 660  mmhg
           R(gas  constant)  =  62.364 l.mmhg/mol.K
           T(temperature)= 25 +273 =   298 k

by  making  n  the subject of the  formula

n= Pv/ RT

n is therefore=   (660mm hg  x11 L)/(  62.364 L.mmhg/mol.k  x298 K)  = 0.391  moles

7is b8 is d9 is c10 is a11 is d