Question

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?

Answer 1

`"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`.