Calculate the molarity of a solution containing 20.7 g of potassium ca

1.	Calculate the molarity of a solution containing 20.7 g of potassium carbonate dissolved in 500 mL of solution.
Answer» This is how you CRACK it up; Molarity=NUMBER of MOLES/volume of solution since we do not have the number of moles, but INSTEAD we have the mass We SAY: Number of moles= mass/molar mass ∴No of moles=20.7g/138.205g/mol = 0.149mol ∴molarity=0.149mol/500mL molarity= 0.000298mol/mL or (0.000298M)

Calculate the molarity of a solution containing 20.7 g of potassium carbonate dissolved in 500 mL of solution.

Answer»

This is how you CRACK it up;

Molarity=NUMBER of MOLES/volume of solution

since we do not have the number of moles, but INSTEAD we have the mass

We SAY: Number of moles= mass/molar mass

∴No of moles=20.7g/138.205g/mol

= 0.149mol

∴molarity=0.149mol/500mL

molarity= 0.000298mol/mL or (0.000298M)