Question

How many oxygen atoms are present in 50g of $CaC{o}_3$ ?

• A. 3.011 $\times$ ${10}^{23}$
• B. 6.022 $\times$ ${10}^{23}$
• C. 9.033 $\times$ ${10}^{23}$
• D. 12.044 $\times$ ${10}^{23}$

Answer 1

The correct option is C

9.033 $\times$ ${10}^{23}$

Molecular Mass of $CaC{o}_3$ = (40 $\times$ 1) + (12 $\times$ 1) + (16 $\times$ 3) = 100g
$\therefore$ 100g of $CaC{o}_3$ = 1 mole of $CaC{o}_3$
50g of $CaC{o}_3$ = 0.5 mole of $CaC{o}_3$
$1moleofCaC{o}_3=3\times 6.022\times {10}^{23}atomsofOxygen0.5moleofCaC{o}_3=\frac{3}{2}\times 6.022\times {10}^{(}23)atomsofOxygen=9.033\times {10}^{23}atomsofoxygen$