WCH11 June 2022

2.​​ A sample of nitrogen gas contains 1.204×1022​​ molecules.

What is the mass of this sample?

[Ar​​ N = 14.0 Avogadro constant (L) = 6.02×1023mol−1]

A 0.14g

B 0.28g

C 0.56g

D 1.12g

ANSWER

C​​  0.56g

Analysis of Option/Explanation

Step 1: Calculating Moles by ratio method

1 mole of substance=6.02×1023 molecules

X mole of substance when= 1.204×1022

Therefore,​​ 

X mole= 0.019 mol of N2

Step 2: Calculating Mass by using formula

moles=massMr

mass in gram=0.019 mol ×28

mass in gram=0.532 gram

Hence, Option C is the correct answer.