the specific gravity of a solution of KOH at 15 Celcius is 1.0824 and contains 0.813 lb KOH per gal of solution. What are the mass fractions of KOH and H2O in the solution?

Question

anonymous · Answer

if you could help me with the steps

anonymous · Answer

In order to determine the mass fraction of something, you take the amount of mass of the component over the overall mass of the solution, solid, etc. 

In this case, they give you the overall mass and the mass of KOH. The mass fraction of KOH is (.813 g KOH /1.0824 g)= .751

In order to determine the mass fraction of H2O in the solution, subtract the mass of KOH from the total mass to determine the mass of H2O in solution. (1.0824 g -.813 g= .269 g) Then take that mass over the total mass (.269 g H2O/ 1.0824 g = .249

You should notice that the mass fraction of KOH + the mass fraction of H2O is equal to one. Your mass fraction for all of the parts should equal 1 as you have accounted for all the mass.