Answer:
a laboratory technician needs to make a 90% liter batch of a 20% acid solution. How can the laboratory technician combine batch of an acid solution that is pure acid with another that that is 10% to get the desired concentration.
a laboratory technician needs to make a 90 liter batch of a 20% acid solution.
How can the laboratory technician combine batch of an acid solution that is pure acid with another that that is 10% to get the desired concentration
:
Let x = amt of pure acid
the result is to be 90 liters, therefore
(90-x) = amt of 10% solution required
:
.10(90-x) + x = .20(90)
9 - .1x + x = 18
.9x = 18 - 9
.9x = 9
x = 9/.9
x = 10 liters of pure acid required
then
90 - 10 = 80 liters of the 10% solution required
:
:
See if that checks out
.10(80) + 10 = .20(90)
8 + 10 = 18; confirms our answer