Question

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

Characteristics of a Gas

Characteristic	Description
Compound	Oxygen gas
Condition	STP
Mass	4.8 grams

What is the expected density of the above sample of gas?

1.90 g/L

1.82 g/L

1.56 g/L

1.43 g/L

Answer 1

We have relation, density of gas ( d ) = P M / R T

Where, P is a pressure of a gas, M is molar mass of a gas , T is a temperature of a gas.

We have, P = 1.00 atm , R = 0.082057 L atm mol ^-1 K ^-1 , T =273.15 K , M =32.00 g / mol

Putting above values in equation 1 , we get

d = 1.00 atm 32.00 g / mol / ( 0.082057 L atm mol ^-1 K ^-1 273.15 K )

d = 32.00 g / ( 22.41 L )

d = 1.4279 g / L

ANSWER : Density of the oxygen gas at STP = 1.43 g / L