Question

A science teacher has a supply of 5% hydrochloric acid and a supply of 65% hydrochloric acid (HCl). How much of each solution should the teacher mix together to get 42 mL of 45% HCl for an experiment? (1 point)
The teacher will need 14 mL of the 5% solution and 28 mL of the 65% solution.
The teacher will need 28 mL of the 5% solution and 14 mL of the 65% solution.
The teacher will need 14 mL of the 5% solution and 14 mL of the 65% solution.
The teacher will need 28 mL of the 5% solution and 28 mL of the 65% solution.

Answer 1

5% A + 65% B = 45% ( A + B )
A + B = 42

0.05 (42 - B) + 0.65 B = 0.45 x 42
2.10 - 0.05 B + 0.65 B = 18.90
0.60 B = 16.80
B = 28

A = 42 - B = 14

The teacher will need 14 mL of the 5% solution and 28 mL of the 65% solution.

Answer 2

thx

Answer 3

Np