How to calculate ratio by weight

Question

For example, how many g of Na and Cl exactly needed to form salt if nothing is left about combination? What are the steps? If only molar mass is given, is it true it must be experimented to get the results?

Answer 1

The formula of common salt (NaCl) has to be known.

Molar mass of Na = 23.0 g mol-1
Molar mass of Cl = 35.5 g mol-1
Molar mass of NaCl = 23.0 + 35.5 = 58.5 g mol-1

In NaCl, mole ratio Na : Cl = 1 : 1
1 mol of NaCl contains 1 mol of Na and 1 mol of Cl.
In other words, 58.5 g of NaCl contain 23 g of Na and 35.5 g of Cl.
Mass ratio Na : Cl = 23 : 35.5

Suppose m g of NaCl is prepared.
Mass of Na = (23/58.5)m = 0.393m g
Mass of Cl = (35.5/58.5)m = 0.607m g