Use the dilution relationship (Mi x Vi = Mf x Vf) to calculate the volume of 0.500 M NaOH needed to prepare 500 mL of .250 M NaOH.
This is my work
? L Solution = 500mL x (1L/1000mL) = .500L
? mol NaOH = .500 L Solution x (0.250 M NaOH/1 L Solution) = .125 mol NaOH
? L solution = .125 mol NaOH x (1L Solution/.500 mol NaOH) = .25
The problem then asks me to round my answer to the nearest ones place, so i have a feeling this equation has an error. Can anyone guide me to getting it right? Thanks!
Why did you shift to liters as the unit of volume. I would have used ml as the volume unit, I suspect that is what the problem intended (but did not say so).
Aren't you looking for the molarity in this equation. If so, the molarity equation is M = moles of solute / Liters of Solution
You didn't follow the instructions and I don't see that you used MxV= MxV
?? mL x 0.500 M = 500 mL x 0.250 M
?? mL = 500 x 0.250/0.500 = 250 mL.
No, you aren't looking for the molarity. You have molarity of solution 1 and you have molarity of solution 2. You are looking for volume (and you solved for that and obtained 0.250 L which is the same as 250 mL). So I would round my answer to 250 mL.
Alright, I see my error. I appreciate the help :)
Let's go through the steps to calculate the correct volume of 0.500 M NaOH needed to prepare 500 mL of 0.250 M NaOH.
Step 1: Write down the given information:
- Initial concentration (Mi): 0.500 M
- Initial volume (Vi): unknown
- Final concentration (Mf): 0.250 M
- Final volume (Vf): 500 mL
Step 2: Convert the final volume to liters:
Vf = 500 mL x (1 L/1000 mL) = 0.500 L
Step 3: Rearrange the dilution equation to solve for the initial volume (Vi):
Mi x Vi = Mf x Vf
Vi = (Mf x Vf) / Mi
Step 4: Substitute the known values into the equation and calculate Vi:
Vi = (0.250 M x 0.500 L) / 0.500 M
Vi = 0.125 L
Step 5: Convert the initial volume to milliliters (rounding to the nearest one's place as requested):
Vi = 0.125 L x (1000 mL/1 L) ≈ 125 mL
So, the correct volume of 0.500 M NaOH needed to prepare 500 mL of 0.250 M NaOH is approximately 125 mL.