The atomic mass of Cl is 35.45 amu and the atomic mass of Al is 26.98 amu. What are the masses in grams of 4.000 mol of Al atoms and of 4.000 mol of Cl atoms?
4.000 mol Cl has a mass of 141.8 g.
4.000 mol Al has a mass of 107.9 g.
The molar mass of an element is its atomic weight (relative atomic mass) on the periodic table in g/mol.
The molar mass is the mass of one mole of a substance. Multiply the molar mass times 4.000 mol to get the mass of 4.000 mol of each element.