Molar mass Na2CO3 = 106 g/mole
Using dimensional analysis:
0.787 moles Na2CO3 x 106 g/mole Na2CO3 = g Na2CO3
Answer = 83.4 g Na2CO3
The answer is to increase the surface area of the solute.
You see it dissolves faster because there is a lot more water touching it when it is has a higher surface area.This can be achieved by crushing
When we have Ksp CaSO4 = 9.1x10^-6 so by substitution in Ksp formula:
Ksp CaSO4 = [Ca+2][SO4]
1.9x10^-6 = [Ca+2][1.5x10^-2]
∴ [Ca+2] M in the solution =1.27x10^-4
when percent remaining = [Ca in solution]/[C original value] * 100
= [(1.27x10^-4*(50ml+50ml)]/[1.28x10^-2*50ml]*100
≈ 2%
