who can help with math please?
a chemistry teacher needs to make 150L of 42% sulfuric acid solution. the acid solutions available are 30% and 50% sulfuric acid, by volume. How many litres pf each solution must be mixed to make the 42% solution? round your answer to the nearest tenth of a L.
if you can please show your work, thank you.
- ranjankarLv 77 years agoFavorite Answer
Let the quantity of 50% acid solution mixed be x L
THEN , the quantity of 30% acid solution mixed WILL BE ( 150- x) L
0.50x + 0.30 ( 150 -x ) = 0.42 *150
0.50x + 45 - 0.30x = 63
0.20x = 18
x = 90
ANSWER 90L of 50% AND 60L of 30% acid solution
- Ian HLv 77 years ago
The total amount of sulfuric acid will be 42% of 150L and this comes from the two contributions.
Let required volume of 30% be V.
Since the total volume will be 150L, the volume of 50% must be 150 - V
Try to learn this method.
0.3V + 0.5(150 - V) = 0.42 * 150L
75 - 63 = 0.2V
V = 12*5
Volume of 30% required is V = 60L
This mixes with 90L of 50% sulfuric acid
Regards - Ian
- JeremyLv 57 years ago
After teaching for the past 9 years, I have discovered these percent-mixture problems are the hardest algebra problems for students to solve.
The easiest way (I believe) to come up with the proper equation to solve is by creating a table...
on the first row (horizontal) would be 3 entries:
" %, Amount, Total "
where % is the percent of the mixture, Amount is the amount of that mixture, and Total is the product of (% and Amount).
%, Amount, Total
30, x, 0.3(x)
50, 150 - x, 0.5(150 - x)
42, 150, 0.42(150)
the equation formed is:
0.3x + 0.5(150 - x) = 0.42(150)
- 0.2x + 75 = 63
- 0.2x = - 13
x = 65
so 65 L of the 30% sulfuric acid, and
(150 - 65)
85 L of the 50% sulfuric acid.Source(s): by the way, notice that Amount (1) + Amount (2) is the total Amount of the combined mixture in each of these. here's another set of problems just like this with different variations: http://answers.yahoo.com/question/index?qid=201309...