What explains the relationship among elements, compounds & mixtures

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4al(s)+3o2(g)→2al2o3(s) a) 1 molal, 1 mol o2 b) 4 molal, 2.6 mol o2 c) 16 molal, 13 mol o2 d) 7.4 molal, 6.5 mol o2

How many grams of phosphorus are contained in 5.09 moles of phosphorus?