Convert particles to moles: 8.3 x 10^20 atoms Cu

Explanation:

We are asked to convert particles to moles.

1 mole of any substance contains the same number of particles (atoms, molecules, formula units). This is Avogadro's Number or 6.022*10²³.

In this problem, the particles are atoms of copper. So, 1 mole of copper contains 6.022*10²³ atoms of copper

Use Avogadro's Number to make a ratio.

We are trying to convert 8.3*10²⁰ atoms of copper to moles, so we multiply that value by the ratio.

The units of "atoms Cu" will cancel.

Condense the expression into 1 fraction.

The original measurement of atoms has 2 significant figures, so our answer must have the same. For the number we calculated that is the ten-thousandths place.

The 7 in the hundredth thousandth place tells us to round the 3 up to a 4.

8.3*10²⁰ atoms of copper are equal to 0.0014 moles of copper.