The characteristics of a certain gas are listed in the table.

Characteristics of a Gas
Characteristic Description
Compound Nitrogen gas
Condition STP
Mass 3.6 grams

What is the expected density of the above sample of gas?
1.66 g/L
1.51 g/L
1.25 g/L
1.17 g/L

1.25 g/L is the expected density of N₂

Explanation:

N₂ (nitrogen gas) → It is a dyatomic gas

Molar mass = 28 g/mol

Let's convert the mass to moles, in order to find the volume by the Ideal Gases Law:

3.6 g / 28 g/mol = 0.128 moles

At STP, pressure is 1 atm and T° is 273K

P . V = n . 0.082 . T → 1 atm . V = 0.128 mol . 0.082 . 273 K

V = (0.128 mol . 0.082 . 273 K) / 1 atm → 2.87 L

Let's find out density → mass / volume

N₂ density = 3.6 g / 2.87L = 1.25 g/L