What is the number of carbon atoms present in $0.35 \ mol$ of $C_6H_{12}O_6$?

$2.8 \times 10^{-3} \ mol$ of $CO_2$ is left after removing $10^{21}$ molecules from its '$x$' $mg$ sample. The mass of $CO_2$ taken initially is. Given: $N_A = 6.02 \times 10^{23} \ mol^{-1}$. (in $mg$)

The mass of $0.1 \ mol$ of methane $(CH_4)$ is .......... $g$.

$A$ sample of $[Cu(NH_3)_4]SO_4$ contains $2.4 \times 10^{24}$ ammonia molecules. The moles of $[Cu(NH_3)_4]SO_4$ in the given sample will be:

The number of atoms in $4.25 \ g$ of $NH_3$ is approximately

If $100 \ mL$ of a urea solution contains $6.022 \times 10^{20}$ molecules,what is the concentration of the urea solution in $M$?