The mass of 800cm3 of gas Q at s.t.p. is 1.0g. What is the molar mass of Q? [Avogadros constant = 22.4dm3 mol-1`]
-
A.
18.0 gmol-1 -
B.
22,4gmol-1 -
C.
28.0gmol-1 -
D.
36.0 gmol-1
Correct Answer: Option C
Explanation
Imole Q occupies 22400 cm3
x mole occupies 800 cm3
x = (frac{800 x 1}{22400})
= 0.036mol
Molar mass = Mass ÷ Mole
= 1 ÷ 0.036
Molar mass ≈ 28 g/mol