Question

Calculate the molarity of 20% ( by mass) K2 CO3

Answer 1

Explanation:

Mass of K

2

CO

3

=20.7g

Molar mass of K

2

CO

3

=138gmol

−1

Moles of K

2

CO

3

=

138gmol

−1

20.7g

=0.15mol

−1

Mass of solution =(500mL)×(1gmL

−1

)

=500 g

Amount of water = 500 - 20.7

= 479.3 g Molarity

=

Mass of solvent in gram

Moles of solute

×1000

=

479.3g

0.15mol

×1000gkg

−1

=0.313molkg

−1

or=0.313