Which containe the most moles: water, aluminum, salt, baking soda

I’m going to assume that you were talking about the mass of one mole of each molecule/element. You do this by knowing the chemical formula and knowing the mass of the elements which can be found in a period table.
Water= H2O
H ≈ 1
O ≈16
Since there is two H multiply one by 2 and add 16 to it.
You get 18 so it’s 18g/mol

Aluminum is an element so you just have to go to the periodic table and look Al. You should get a number that is about 26.98.
So 26.98 g/mol is the answer

Salt=NaCl
Na ≈22.99
Cl ≈ 35.45
When you add those up you get 58.44 g/mol

Baking soda = NaHCO3
Na ≈22.99
H ≈1
C ≈12
O ≈16
Multiply 16 by 3 to get 48 and add everything together to get 83.99g/mol.
So if you had one mol of each the answer would be baking soda

If there are amount of miles that you forgot to add for the comparison, you just have to multiply.
For example
1 mol water is 18g/mol
.5mole water is 9g/mol
(.5*18 =9)
5 miles of water is 90g/mol
(5*18 = 90$

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom.