The total number of protons in 10 g of calcium carbonate is $\left({\mathrm{N}}_0=6.023\times {10}^{23}\right)$   

$\because 100 \mathrm{gm} {\mathrm{CaCO}}_3=6.023\times {10}^{23}\text{ molecules }$
$\therefore 10 \mathrm{gm} {\mathrm{CaCO}}_3=\frac{6.023\times {10}^{23}}{100}\times 10$
$=6.023\times {10}^{22}\text{ molecules }$
1 molecule of CaCO₃ = 50 protons
$6.023\times {10}^{22}\text{ molecule of }{\mathrm{CaCO}}_3=50\times 6.023\times {10}^{22}$
$= 3.0115 \mathrm{x} {10}^{24}$