A #283.3*g# mass of an elemental gas #X# exerts a pressure of #3.2*atm# at a temperature of #300*K#, while it is enclosed in a #30*L# volume. What is the identity of the element?

1 Answer
May 10, 2017

Answer:

#"Element X"-=Cl#

Explanation:

We use the ideal gas equation..........

#n=(PV)/(RT)=(3.2*atmxx30*L)/(0.0821*(L*atm)/(K*mol)xx300*K)#

#=3.90*mol#

But since we KNOW the mass of this gas;

#"Molar mass"="Mass of gas"/"Molar quantity of gas"#

#(283.3*g)/(3.90*mol)=72.6*g*mol^-1#

Since we know that this is a binuclear element, i.e. #X_2#, the atomic mass of the element is approx. #36*g*mol^-1#. Chlorine is the likely candidate, #"atomic mass" =35.45*g*mol^-1#. And note that chlorine, like most of the other elemental gases is BINUCLEAR, i.e. #X_2#.