Question

At STP 11.21 of a gas has a mass of 22 g, molecular weight of
the gas is
(a) 22
(b) 44
(c) 11
(d) 88
​

Answer 1

(A) 22

hope it will help u dear

Answer 2

Answer:

(c) 11 g

Procedure:

How to reach final answer?

Volume    $\longrightarrow$  Moles  $\longrightarrow$  Molar mass

• Use STP volume relation to find moles.
• Use moles and given mass to get final molar mass.

Explanation:

#Using volumes to find moles

Volume of 1 mole of an ideal gas at STP = 22.4 L

Volume of this gas at STP =  11.21 L

Let the no of moles be x,

Now using ratios,

$\\\tt \dfrac{22.4}{11.21} = \dfrac{1}{x}$

#Using moles to find mass with given data

Solving for x returns 1.99 approximately equal to 2.

There are 2 moles of the gas in 11.21 L,

Now that we know that these 2 moles weigh 22g,

Therefore one mole must weigh 11 g.