The molecular weight of Potassium carbonate (K₂CO₃) is 138.2055.

Potassium carbonate (K₂CO₃) is an inorganic compound of three elements: Potassium, Carbon, and Oxygen. The molecular weight of Potassium carbonate is 138.2055 which can be calculated by adding up the total weight (atomic weight multiplied by their number) of Potassium, Carbon and Oxygen.

To calculate molecular weight of any compound, the first step is to know the constituent elements (atoms) and their number in that particular compound. Then calculate the total atomic weight of each element by multiplying its atomic weight by its number. The sum of total atomic weight of all constituent elements will be the molecular weight of the compound. Note that the value of atomic weight may differ from different sources.

CALCULATION PROCEDURE: Potassium carbonate [K₂CO₃] Molecular Weight Calculation

Step 1: Find out the chemical formula and determine constituent atoms and their number in a Potassium carbonate molecule.
From the chemical formula, you will know different atoms and their number in a Potassium carbonate molecule. Chemical formula of Potassium carbonate is K₂CO₃. From the chemical formula of Potassium carbonate, you can find that one molecule of Potassium carbonate has two Potassium (K) atoms, one Carbon (C) atom and three Oxygen (O) atoms.

Step 2: Find out atomic weights of each atom (from periodic table).

Atomic weight of Potassium (K): 39.0983 (Ref: Ciaaw-potassium)
Atomic weight of Carbon (C): 12.0107 (Ref: Jlab-ele006)
Atomic weight of Oxygen (O) : 15.9994 (Ref: Jlab-ele008)

Step 3: Calculate the molecular weight of Potassium carbonate by adding the total weight of all atoms.

Number of Potassium atoms in Potassium carbonate: 2
Atomic weight of Potassium: 39.0983
Total weight of Potassium atoms in Potassium carbonate: 39.0983 x 2 = 78.1966

Number of Carbon (C) atoms in Potassium carbonate: 1
Atomic weight of Carbon: 12.0107
Total weight of Manganese atoms in Potassium carbonate: 12.0107 x 1 = 12.0107

Number of Oxygen (O) atoms in Potassium carbonate: 3
Atomic weight of Oxygen: 15.9994
Total weight of Oxygen atoms in Potassium carbonate: 15.9994 x 3 = 47.9982

Step 4: Calculate the molecular weight of Potassium carbonate by adding up the total weight of all atoms.

Molecular weight of Potassium carbonate : 78.1966 (Potassium) + 12.0107 (Carbon) + 47.9982 (Oxygen) 

So the molecular weight of Potassium carbonate is 138.2055.

Potassium carbonate [K₂CO₃] Molecular Weight Calculation

REFERENCES:

• Ciaaw-potassium : https://www.ciaaw.org/potassium.htm
• Jlab-ele006; https://education.jlab.org/itselemental/ele006.html
• Jlab-ele008: https://education.jlab.org/itselemental/ele008.html

See also:

• Hydrogen chloride molecular weight calculation