How much water to be added to 450 ml of a solution 0.5 M to obtain a concentration 0.30 M?

0.5 mols/ liter * 0.45 liters = 0.225 moles

.225 moles= 0.30 mols/liter * V liters
V = 0.75 liters final volume
0.75 - 0.45 = 0.30 liters added
which is 300 mL

since the amount of solute does not change,

0.30(450+x) = 0.50*450
x = 300

To calculate the amount of water that needs to be added to a solution to obtain a desired concentration, we need to use the formula:

C1V1 = C2V2

Where:
C1 = initial concentration of the solution in M (0.5 M)
V1 = initial volume of the solution in mL (450 mL)
C2 = desired concentration of the solution in M (0.30 M)
V2 = final volume of the solution in mL

We can solve for V2 to determine the final volume of the solution. Let's plug in the given values:

(0.5 M)(450 mL) = (0.30 M)(V2)

225 = 0.30V2

Now, divide both sides of the equation by 0.30 to isolate V2:

V2 = 225 / 0.30

V2 ≈ 750 mL

Therefore, to obtain a concentration of 0.30 M, you would need to add approximately 750 mL of water to the 450 mL solution.