# How many copper atoms are there in a mole of copper atoms? What is the number of copper atoms in 6.4*g?

Jun 12, 2017

We work out the molar quantity.......and get $6.022 \times {10}^{22}$ $\text{copper atoms}$..............

#### Explanation:

From your Periodic Table we learn that one mole of copper, $6.022 \times {10}^{23}$ individual copper atoms have a mass of $63.55 \cdot g$. And thus we use the MASS of a chemical sample to calculate the NUMBER of atoms and molecules. This is the principle of chemical equivalence, and you will do many of these calculations over the next few years......

Given that we know that if there are $63.55 \cdot g$ copper there are ${N}_{A}$, $\text{Avogadro's number}$ of copper atoms.........we take the quotient.....

$\frac{6.4 \cdot g}{63.55 \cdot g \cdot m o {l}^{-} 1} \times 6.022 \times {10}^{23}$ ${\text{copper atoms mol}}^{-} 1$.

$\equiv 6.022 \times {10}^{22}$ $\text{copper atoms}$..............