# Show how to calculate the molar mass of a compound by using the periodic table of elements.?

for example let's wok with the molecule NaCl

At the Periodic Table (PT), you have the mass of the element. For Na it is around 23.00, and for Cl it is around 35.45. The units for those are grams per mole.

So the MOLAR MASS for NaCl is (23.00 + 35.45) = 58.45g/mol

another example: CH3CO2H
C = 35.45
H = 1.01
O= 16.00

So, the molar mass of CH3CO2H will be:
35.45 + (3 x 1.01) + 35.45 + (2 x 16.00) + 1.01
which is equal to: 106.94 g/mol

Find the atomic weight of the all elements in the compound. For each, multiply by the number of atoms in the molecule and total.

H2SO4 - 1 * 1 for hydrogen plus 1 * 32 for sulfur plus 4 * 16 for oxygen.
For NaCl, sodium weighs 23 grams and chloride weighs 35.5 g, so you simply add these to get 58.5 grams. This is the molar mass. If you have H2O, you must multiply the weight of the hydrogen by two and add the 16 grams of Oxygen to get 18 grams.

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