Terms in this set (96)

So, we're gonna add solute to increase the concentration and we want to increase it to 50%.
Notice the amount of HNO3 is 60 * 4/10= 24 L

So, C is a nice round number, so we'll just pick C as our answer. Before you even pick it, notice that the amount of solute in the beginning solution, 40% of 60 is 24 liters. There are 24 liters of the acid in the initial solution. So, now let's pick C. We add 20 more liters of acid, as that means that we have a total concentration of 44 liters, that is the amount of acid in the solution and of course, the total solution, the volume of the solution is gonna be 80 liters and so we wanna know do we have the right concentration.
So C= 20 so 20 L added
Total concentrate = 24 + 20 = 44 L
Total solution = 60 + 20 = 80 L
Well, we don't have to do the division. We can see that 44 is more than half of 80. So we don't even note, need to know the exactly number. All we need to know is the concentration would be over 50%, so this is too high. We've added too much acid. So right away, we can eliminate C, D, and E.
All of those add too much acid. So now we have to pick either A or B, it doesn't matter. I'll just pick A. Suppose we add 12 liters of acid. Well now the total concentrate is 24 plus 12, 36 liters of acid. So that's how many liters of acid total would be in the solution, and at that point of volume, the total volume of the solution would be 72, and notice that 36 is exactly half of 72 so this would be a 50% solution, this answer actually works, so we picked the right answer here, the answer is A.
ok we try A=12
total concentrate = 24 + 12= 36 L
total solution=