Question

Number of oxygen atoms present in $1$ gram of calcium carbonate is:

• A. $6\times {10}^{21}$
• B. $1.8\times {10}^{22}$
• C. $6\times {10}^{22}$
• D. $8\times {10}^{22}$

Answer 1

The correct option is B $1.8\times {10}^{22}$

The molecular weight of calcium carbonate is $100$ g per mole.

$1$ g of calcium carbonate corresponds to $0.01$ mole.

$1$ mole of calcium carbonate contains three oxygen atoms.

Thus, $0.01$ mole of calcium carbonate will contain $0.03$ moles of oxygen atoms which is equal to $0.03\times 6.02\times {10}^{23}=1.8\times {10}^{22}$ oxygen atoms.

Hence, option B is correct.