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