Question

Total number of atoms in $20g$ of calcium carbonate _________.

Answer 1

Molecular weight of $CaC{O}_3$ is 100. So, number of moles present in $20g$ of $CaC{O}_3$ are $20/100=0.2$. Each molecule of $CaC{O}_3$ has 5 atoms. So, total no. of atoms present are $0.2\times 5.Na=6.023\times {10}^{23}$