Question

Arrange the following in order of increasing mass :
(i) 1 mole of N₂, (ii) 0.5 mole of O₃, (iii) \(3.011×10^{23}\) molecules of O₂, (iv) 0.5 gram atom of O₂

• A. iv<iii<ii<i
• B. iv<i<iii<ii
• C. iii<ii<iv<i
• D. i<iii<ii<iv

Answer 1

The Correct Option is A

To compare the masses of different substances, we use the number of moles and their respective molar masses: 

I) O₃

Mass = Number of moles × Molar mass

$= 0.5 \times 48 = 24$ g

II) O (one gram atom)

Mass = Number of moles × Molar mass

$= 0.5 \times 16 = 8$ g

III) O₂ molecules

Given number of molecules = $3.011 \times 10^{23}$

Moles of $O_2$ = $\frac{3.011 \times 10^{23}}{6.022 \times 10^{23}} = 0.5$ moles

Mass = $0.5 \times 32 = 16$ g

IV) CO₂ gas at NTP

Volume = 5.6 L

Moles = $\frac{5.6}{22.4} = 0.25$ moles

Mass = $0.25 \times 44 = 11$ g

Comparing masses:
IV = 11 g
III = 16 g
II = 8 g
I = 24 g

Arranged in increasing order:
IV < II < III < I

Correct option: (A) iv < iii < ii < i