An unknown diatomic gas has a density of 3.164 g/l at stp. What is the identity of the gas?

The identity of the gas is Cl₂ (chlorine)

Explanation:

STP conditions are:

1 atm → Pressure

273.15 K → T°

So, we must use the Ideal Gas Law to get the moles.

Before that, we will think density as data where 3.164 g of diatomic gas are contained in 1 L of volume.

P. V = n. R. T

1 atm. 1 L = n. 0.082 L. atm/mol. K. 273.15K

1 L. atm / (0.082 L. atm/mol. K. 273.15K) = n

0.0446 mol = n

This quantity of diatomic gas, are 3.164 g so the molar mass will be:

Mass / mol = molar mass

3.164 g / 0.0446 mol = 70.9 g/m

The element (a diatomic molecule), which has that molar mass in the periodic table is the Cl₂.

1 Cl = 35.45 g/m

Cl₂. = 70.9 g/m