7) Andre added 25mL of water to 75mL of a 5.0M stock solution to make 10 points
100mL. What is the concentration of the new, diluted solution? *

The concentration of the diluted solution is 3.75 M

Explanation:

Step 1: Data given

Volume of a stock solution = 75 mL = 0.075 L

The molarity of stock solution = 5.0 M

We add 25 mL, The total volume is 100 mL = 0.100 L

Step 2: Calculate the concentration of the diluted solution

C1*V1 = C2*V2

⇒with C1 = the initial concentration = 5.0 M

⇒with V1 = the initial volume = 0.075 L

⇒with C2 = the new concentration = TO BE DETERMINED

⇒with V2 = the diluted volume = 0.100 L

5.0 M * 0.075 L = C2 * 0.100L

C2 = (5.0M * 0.075 L) / 0.100 L

C2 = 3.75 M

The concentration of the diluted solution is 3.75 M