Question

Calculate the weight of the following gas which occupy a volume of 3.36 dm³ at STP:

hydrogen

Answer 1

Concept used:

According to the mole concept, one mole is the amount of the gas which has a volume of 22.4 l at STP.

Also, 1 mole= Gram molecular weight

Therefore, Gram molecular weight= 22.4 l of the substance at STP

Or Gram molecular weight= 22.4 dm³ of the substance at STP (1 litre= 1 dm³)

Step-1: Calculation of the gram molecular weight of Hydrogen (H₂)

Gram atomic weight of Hydrogen (H)= 1 g mol^-1

Gram molecular weight of Hydrogen gas (H₂)= 2 (1g mol^-1 )= 2 g mol^-1

Step-2: Calculation of weight in a volume of 3.36 dm³ at STP

For Hydrogen gas, Molecular weight is 2 g.

22.4 dm³ of Hydrogen gas (N₂) weighs= 2 g

1 dm³ of Hydrogen gas (H₂) weighs= $\frac{2}{22.4}$ g

3.36 dm³ of Hydrogen gas (H₂) weighs= $\frac{2}{22.4}\times 3.36=\frac{6.72}{22.4}=0.3$ g

Therefore, the weight of the Nitrogen gas which occupy a volume of 3.36 dm³ at STP is 0.3 g.