Define the following term:

Moles in terms of number.

How are the number of moles $\left(\mathrm{n}\right)$ of a substance calculated from its mass $\left(\mathrm{m}\right)$?

How is the number of moles$\left(\mathrm{n}\right)$ of a substance calculated from its number of molecules $\left(\mathrm{N}\right)$?

How many atoms are present in $1$ mole of hydrogen gas?

Calculate the number of moles in the following :

$10.0\mathrm{g}$ of ${\mathrm{CaCO}}_3$

(Atomic masses:$\mathrm{Ca}=40\mathrm{u}, \mathrm{C}=12.0\mathrm{u}, 0=16.0\mathrm{u}$)

Calculate the number of moles in the following :

${10}^{23}$ molecules of ${\mathrm{CO}}_2$.

What is the mass of  $2.5$ moles of ${\mathrm{Cl}}_2$?

What is the mass of $0.5$ moles of ${\mathrm{CO}}_2$?