Question

Which of the following contains same number of atoms as in 2.4 g of carbon?

• A. 0.1 moles of oxygen
• B. 2.8 g of nitrogen
• C. 2 g of hydrogen
• D. 35.5 g of chlorine

Answer 1

Answer: (A), (B)

The correct options are
A 0.1 moles of oxygen
B 2.8 g of nitrogen

Let N be the avogadro's number.
Number of atoms in 2.4 g of $C=\frac{2.4g}{12g/mol}\times N=0.2N$
(A) 0.1 moles of $O_2=2\times 0.1\times N=0.2N$ atoms.
( 1 $O_2$ molecule $=2O$ atoms).
(B) 2.8 g of $N_2=\frac{2.8g}{28g/mol}\times 2\times N=0.2N$ atoms.
(C) 2 g of $H_2=\frac{2g}{2g/mol}\times 2\times N=2N$ atoms.
(D) 35.5 g of $C{l}_2=\frac{35.5g}{35.5g/mol}\times 2\times N=2N$ atoms.
Hence, (A) and (B) contains same number of atoms as in 2.4 g of carbon.