Calculate the number of moles of a gas if it occupies a volume of 4dm at 10atm and _200°c.

 The number  of moles of a gas if it occupy a volume of 4dm  at 10 atm and - 200 c   is 6.67  moles

  calculation
by use of ideal gas equation
that is PV =nRT
where  P(pressure) =  10 atm
           V( volume) =  4dm^3 = 4L
            n(number of moles) =?
             R(gas constant) = 0.0821 L.atm/mol.K
              T = -200  +273 =  73 K

make n the  formula  of  the subject  n = PV/RT

n is therefore =  (10 atm x 4l)/(0.0821 L.atm/mol.K  x 73 K)  =  6.67 moles

The answer is 323 g.

A) the enthralling of formation for pure element in its standard state is always positivehope this : )