A prescription is written for 500 mL of a 7% NaCl solution. The technician has a 50% NaCl solution. What volume of 50% NaCl is required for the 7% solution?
mL

70 mL

Explanation:

To solve this problem we can use the C₁V₁=C₂V₂ equation, where the subscript 1 refers to the concentrated solution while subscript 2 refers to the diluted one, as follows:

We input the data:

And solve for x:

Thus the answer is 70 mL.

tracks, burrows, eggshells, nests, tooth marks, or gastroliths

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.