Question

Calculate the number of moles of oxygen in ten moles of calcium carbonate

Answer 1

In one mole of CaCO3 there are 3 oxygen atoms.
In Ten moles of CaCo3 there are 30 mole of Oxygen

prove -

Using Unit Factor Method
10 mole of CaCo3 ( 3 mole of O/1mole of CaCo3)
= 30 mole of Oxygen