Question

What would the concentration of the resulting glucose solution be if 200 mL of a 22 % (m/v) glucose solution were diluted to a final volume of 1 L with distilled water? Express your answer using one significant figure.

How many liters of a 0.85 % (m/v) NaCl solution can be prepared from 700 mL of a 9.5 % (m/v) stock solution? Express your answer using two significant figures.

Answer 1

1)

use dilution formula

M1*V1 = M2*V2

1---> is for stock solution

2---> is for diluted solution

Given:

M1 = 22 %

V1 = 200 mL

V2 = 1000 mL

use:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 = (22*200)/1000

M2 = 4.40 %

Answer: 4 %

2)

use dilution formula

M1*V1 = M2*V2

1---> is for stock solution

2---> is for diluted solution

Given:

M1 = 9.5 M

M2 = 0.85 M

V1 = 700 mL

use:

M1*V1 = M2*V2

V2 = (M1 * V1) / M2

V2 = (9.5*700)/0.85

V2 = 7824 mL

V2 = 7.82 L

Answer: 7.8 L