UPSEE Solved Model Paper 4

Mass of 3.01 × 1023 molecules is 32 grams
Mass of 1 molecule is

32

3.01

×

1

1023

grams.
Thus, mass of 6.023 × 1023 molecules is

32

3.01

×

1

1023

× 6.023 × 1023 grams, which is almost equal to 64 grams.
Thus, 64 grams is the molecular weight of the gas
One mole of any gas occupy 22.4 L at STP.
64 grams occupy 22.4 L at STP.
1 gram occupy

22.4

64

L at STP.
Thus, 8 grams will occupy

22.4

64

× 8 L at STP , which is equal to 2.80 L.
Thus, option A is the correct answer.