Question

Calculate the concentration of a solution of CO2 in water , which contains 20.25g of CO2 per 675mL of solution.

Answer 1

Concentration (Molarity) = moles of solute/liters of solution

So, you need to convert grams of CO2 to moles and mL to L and then plug those numbers in.

The molar mass of CO2 is 44.01 g/mol, so 20.25g x (1 mole/44.01 g) = 0.46 moles CO2.

And 1000mL = 1L, so 675 mL x (1L/1000mL) = 0.675L solution.

Finally, M=0.46 moles CO2 / 0.675 L solution = 0.68 M.