How many atoms would be found in 1.2 grams of copper?

The mass of copper (Cu) is 63.55 grams.

Remember that 6.022×10²³ atoms = 1 mol (Avogadro's number).

To get from grams to atoms, you need to multiply 1.2 grams of copper × 1 mol of copper × 6.022×10²³ atoms of copper and divide it by 63.54 grams of copper and 1 mol of copper.

This will cancel out the grams and moles to give you the answer in atoms of copper!

1.2 grams of copper × 1 mol of copper              × 6.022×10²³ atoms of copper

                                     63.54 grams of copper x 1 mol of copper

= 1.137×10²² atoms of copper

= round to 2 sig figs: 1.1×10²² atoms of copper