Question

Question #ade66

Answer 1

The answer is `2.15g`.

A solution's percent concentration by mass is defined as the mass of solute divided by the total mass of the solution and multiplied by 100%.

`c= (mass_(solute))/(mass_(solution)) * 100%`

Therefore, the mass of solute needed for this solution is

`m_(K_2CO_3) = (c * m_(solution))/100 = (5.00% * 43.0)/(100%) = 2.15g`

It is important to try and estimate what that mass could be even before calculating it; this could have been done by takin the `1/20`th part (the equivalent of 5%) of `43g`, which is roughly `2g`.