Question

1. If I have 100 mL of a 0.15 M NaOH solution and I dilute the solution to a final volume of 250 mL, what will the molarity of the diluted solution be?

2. If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?

3. I have 345 mL of a 1.5 M NaCl solution. If I boil the water until the volume of the solution is 250 mL, what will the molarity of the solution be?

Thank you so much!

Answer 1

1)

use dilution formula

M1*V1 = M2*V2

1---> is for stock solution

2---> is for diluted solution

Given

M1 = 0.15 M

V1 = 100 mL

V2 = 250 mL

Use:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 =(0.15*100)/250

M2 =0.060 M

Answer: 0.060 M

2)

use dilution formula

M1*V1 = M2*V2

1---> is for stock solution

2---> is for diluted solution

Given

M1 = 0.15 M

V1 = 125 mL

V2 = 25 mL + 125 mL = 150 mL

Use:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 =(0.15*125)/150

M2 =0.125 M

Answer: 0.125 M

3)

Given

M1 = 1.5 M

V1 = 345 mL

V2 = 250 mL

Use:

M1*V1 = M2*V2

M2 = (M1*V1)/V2

M2 =(1.5*345)/250

M2 =2.07 M

Answer: 2.07 M