HOW MANY GRAMS OF Mg WILL HAVE THE SAME NUMBER OF ATOMS AS 40.5gOF Al?(Mg=24u,Al=27)

The molar mass of aluminium is 27g. This means that there are 6.022 X 10²³ atoms in 27g of aluminium. So

27g of aluminium = 6.022 X 10²³ atoms of aluminium

1g of aluminium = (6.022 X 10²³ / 27) atoms of aluminium

40.5g of aluminium = (6.022 X 10²³ X 40.5) / 27 atoms of aluminium

= 9.033 X 10²³ atoms of aluminium

We have to find the mass of magnesium which contains 9.033 X 10²³ atoms. The molar mass of magnesium is 24g. This means that there are 6.022 X 10²³ atoms in 24g of magnesium. So

mass 6.022 X 10²³ atoms of magnesium = 24g

mass of 1 atom of magnesium = [24 / (6.022 X 10²³)] g

mass of 9.033 X 10²³ atoms of magnesium = [(24 X 9.033 X 10²³) / (6.022 X 10²³)] g

= 36g

Thus, 36g of magnesium contains the same number of atoms as are present in 40.5g of aluminium.