Molecular weight calculation: 39.0983*2 + 12.0107 + 15.9994*3 Some chemical facts about potassium carbonate are as follows: Chemical formula = K 2 CO 3; Molar mass = 138.2 g/mol; Melting point =891 °C potassium carbonate hydrate. So K+K+C+O+O+O = … ››Potassium Carbonate molecular weight. Potassium carbonate CAS 584-08-7 for analysis EMSURE® ACS,ISO,Reag. MFCD00149925 Ph Eur - Find MSDS or SDS, a COA, data sheets and more information. OK, Well molar mass is the atomic weights added up, times the molar mass constant of (1 g/mol) So potassium carbonate (K2CO3): K=39. 6381-79-9. potassium carbonate water. C=12. Properties of Potassium Carbonate. Well we are trying to make chalk and one of our reactants is Potassium Carbonate. Next, divide the given mass by the molar mass: 2.76g/140 g/mol=0.020 mol (rounded to 2 significant digits). K2CO3 water. Potassium Carbonate Dihydrate K2CO3.2H2O Molar Mass, Molecular Weight First, you need to find the molar mass of potassium carbonate, K2CO3. Molar mass of K2CO3 = 138.2055 g/mol Convert grams Potassium Carbonate to moles or moles Potassium Carbonate to grams. O=16. Our teacher said the Molar Mass of Potassium Carbonate is 165.227 (since its K2CO3-1.5H2O) However according to the internet its just K2CO3, which is just 138 mol So which ones correct? Find the molar mass by adding the atomic masses of all the elements in the compound: 40+40+12+16+16+16=140 g/mol, approximately.