What is the concentration of a solution prepared by diluting 25.0 mL of HCl 0.750 mol/L to a final volume of 500. mL?

molarity = mols/L.

mols HCl = M x L
mols HCl = 0.750 M x 0.025 L = ??
Now M = mols/L= ??/0.500

mols HCl = 0.750 M x 0.025 L = 0.0186 mol

M = 0.0186 mol/0.500 L = 0.0372

the answer is 0.0372 mol/l

I don't know what you teacher prefers but I would not round the 0.750 x 0.0250 = 0.01875. Just leave that in the calculator and divide that number (whatever is in the calculator) by 0.500 and the answer is 0.0375. You are allowed three significant figures. Doing it as you did gives rounding errors. You can see what difference it makes.

Thank you, I made the change. My professor is very precise, so I'm glad you noticed that!

To calculate the concentration of a solution prepared by dilution, we can use the formula:

C₁V₁ = C₂V₂

Where:
C₁ = initial concentration
V₁ = initial volume
C₂ = final concentration
V₂ = final volume

Given:
C₁ = 0.750 mol/L (initial concentration)
V₁ = 25.0 mL (initial volume)
V₂ = 500. mL (final volume)

We need to find C₂ (final concentration).

Step 1: Convert the initial volume to liters:
V₁ = 25.0 mL = 25.0 mL / 1000 mL/L = 0.025 L

Step 2: Convert the final volume to liters:
V₂ = 500. mL = 500. mL / 1000 mL/L = 0.500 L

Now, we can substitute the values into the equation:

C₁V₁ = C₂V₂

(0.750 mol/L)(0.025 L) = C₂(0.500 L)

0.01875 mol = C₂(0.500 L)

Step 3: Solve for C₂:

C₂ = (0.01875 mol) / (0.500 L)

C₂ = 0.0375 mol/L

Therefore, the concentration of the diluted solution is 0.0375 mol/L.