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

What is the symbol for the $SI$ unit of mole? How is the mole defined?

How many moles of oxygen gas at $STP$ are equivalent to $5.6 \ L$?

$A$ flask contains $98 \ mg$ of $H_2SO_4$. If $3.01 \times 10^{20}$ molecules of $H_2SO_4$ are removed from the flask,the number of moles of $H_2SO_4$ remaining in the flask is $\left(N_A = 6.02 \times 10^{23}\right)$

Calculate the total number of atoms in $5.6 \ L$ of $SO_2$ gas at $NTP$.

The number of molecules and atoms present in $7.1 \ g$ of chlorine gas $(Cl_2)$ are respectively: