If there are 365 grams of NaCl, how many grams of sodium are there?

Molar mass is the amount grams that one mole weighs.

Explanation: You need to find the molar mass of NaCl which is the same as the amu on the periodic table in grams. So it is 22.99(Na) + 35.45(Cl) = 58.44

You also know that for every mole of NaCl you have 1 mole of Na because every molecule of NaCl has 1 atom of Na.

Finally, using the periodic table, again, you see that the molar mass of Na is 22.99.

Then using stoichiometry, you can find the grams of sodium.

100(g NaCl) * 1 mol (NaCl)/58.44 g (NaCl) * 1 mol (Na)/ 1 mol (NaCl) * 22.99 (g of Na)/ 1 mol (Na)

which equals 39.339435 g of Na.

If you need to maintain significant figures the answer will be 40.