Sodium thiosulfate pentahydrate (Na2S2O3 · 5H2O) Molar Mass

Molar mass of Sodium thiosulfate pentahydrate (Na2S2O3 · 5H2O) is 248.172 g/mol.

Well, now you have come to know the molar mass of Na2S2O3 · 5H2O.

But how can you get this value?

Let me show you the calculation to get the molar mass of Sodium thiosulfate pentahydrate (Na2S2O3 · 5H2O).

You can also refer to this one minute video which will show you the simple steps to calculate the molar mass of any compounds.

Sodium thiosulfate pentahydrate (Na2S2O3 · 5H2O) Molar Mass Calculation

If you have a periodic table with you, then you can easily calculate the molar mass of Na2S2O3 · 5H2O.

Because the molar mass of any molecule (or compound) can be calculated by simply adding the molar masses of individual atoms.

Now here we have to find the molar mass of Na2S2O3 · 5H2O.

So for that, have a look at the periodic table given below.

You can see the molar mass value of all the atoms from this periodic table.

Now in Na2S2O3 · 5H2O, there are Sodium atom, Sulfur atom, Oxygen atoms and Hydrogen atoms.

So let’s look at the molar mass of Sodium, Sulfur, Oxygen and Hydrogen from the above periodic table.

You can see that;

The molar mass of Sodium is 22.990 g/mol. ^[1]

The molar mass of Sulfur is 32.06 g/mol. ^[2]

The molar mass of Oxygen is 15.999 g/mol. ^[3]

The molar mass of Hydrogen is 1.008 g/mol. ^[4]

Now, to calculate the molar mass of Na2S2O3 · 5H2O, you just have to add the molar mass of all the individual atoms that are present in Na2S2O3 · 5H2O.

So, Molar mass of Na2S2O3 · 5H2O = {(Molar mass of Sodium atom × 2) + (Molar mass of Sulfur atom × 2) + (Molar mass of Oxygen atom × 3)} + [5 × {(Molar mass of Hydrogen × 2) + Molar mass of Oxygen}]
= {(22.990 × 2) + (32.06 × 2) + (15.999 × 3)} + [5 × {(1.008 × 2) + 15.999}]
= {45.98 + 64.12 + 47.997} + [5 × {(2.016) + 15.999}]
= {158.097} + [5 × {18.015}]
= {158.097} + [90.075]
= 248.172 g/mol

Hence the Molar mass of Na2S2O3 · 5H2O is 248.172 g/mol.

I hope you have understood the short and simple calculation for finding the molar mass of Na2S2O3 · 5H2O.

Remember

• In some books, you may see the unit of molar mass as grams/mole or g/mole. But all these units (i.e g/mol, grams/mole and g/mole) are the same. 
• Always follow the calculation order to avoid any mistakes in calculation. First solve the brackets, then multiplications and at last do the final addition.
• And don’t forget to put the unit g/mol to your final calculated molar mass.

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