4.2 moles of copper contains

To obtain one mole of copper atoms (6.02 x 1023 atoms), weigh out 63.55 g copper. The molar mass (M) of a substance is the mass of one mole of entities (atoms, molecules, or formula units) of the substance. Molar mass has units of grams per mole (g/mol).

Where are the questions

The law of conservation of mass states that a mass of an object or the amount of matter composed inside an object or thing will not change unless it is added or removed of the matter that is contained in the object itself.