SS1 Chem concentration Ch 15

Calculate the number of moles of K₂CO₃, K⁺ ions and CO₃²⁻ ions in 25.0 cm³ of 0.20 M K₂CO₃ solution.


No. of moles of K₂CO₃ = MV = 0.2 x (25/1000) = 0.005 mol

1 mole of K₂CO₃ solution contains 2 moles of K⁺ ions and 1 mole of CO₃²⁻ ions.

No. of moles of K⁺ ions = 0.005 x 2 = 0.01 mol …… (answer)

No. of moles of CO₃²⁻ ions = 0.005 mol …… (answer)

K2CO3------------->2K+ +CO3^2-
(25.0/1000)dm^3,0.20mol/dm^3

no. of mol of K2CO3=mol/dm^3Xvolume=A
mol ratio
K2CO3:2K+
A:2A<=mol of K+
mol ratio
K2CO3:CO3^2-
1:1
A:A<=mol of CO3^2-