An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted to a total solution volume of 2.00 L. Calculate the mass percent of the solution. (Assume a density of 1.05 g>mL for the solution.)

Video transcript

Hey everyone today, we're being asked to determine the mass% g of potassium hydroxide is dissolved in 840 ml of solution. So we're being asked to find the mass percent. The mass percent, which is simply the mass of the solute, which in this case is potassium hydroxide divided by the mass of the a solution. Let's try that G mass of the solution Multiplied by 100 because this is a percentage after all. And we know that the mass of the solution is 53 g of potassium hydroxide. So this will be equal to 53 g 53g of K. O. H. But we don't know the mass of the solution. We only have the volume. However, the problem also gives us the Dere of the solution which is 1.2 or three g per centimeter cubed. Which may look daunting because our volume is given in milliliters. But we don't have milliliters in the density. But this is very simple because as we recall, one g per centimeter cubed Is the same thing as one g per middle leader. So if we have 840 mL of potassium hydroxide and the density is 1.3 g liter 1.3 g per milliliter. While our milliliters will cancel out and we will be left with 865.2 g of K O H. So that is the mass of the solution in total. Not a wait sorry of solution, let me fix that over here too solution. So with that in hand, we can go ahead and put this back into our uh equation that we wrote earlier in under 65.2 grams of solution, Multiplied by 100 and we get a final value Of 6.13%. Therefore, the mass% 53 g of potassium hydroxide dissolved in 840 ml of solution is 6.13%. I hope this helps. And I look forward to seeing you all in the next one.