A 50 mL sample of 8% (m/v) NaOH is diluted with water so that the final volume is 200 mL...what is the final concentration and how did you figure it out?
See your 50% acetic acid question.
2.0 %
To find the final concentration, we need to calculate the amount of NaOH present in the diluted solution and then divide it by the final volume.
Step 1: Calculate the amount of NaOH in the original 50 mL solution.
The original solution concentration is 8% (m/v), which means there are 8 grams of NaOH dissolved in 100 mL of solution. To find the amount of NaOH in the 50 mL original sample, we can use the proportion:
(8 g NaOH / 100 mL) = (x g NaOH / 50 mL)
Solving for x, we get:
x = (8 g NaOH / 100 mL) * 50 mL
x = 4 g NaOH
Step 2: Calculate the final concentration.
The amount of NaOH, 4 grams, remains the same when the solution is diluted. However, the final volume of the solution is 200 mL after dilution. Therefore, the final concentration can be calculated using the proportion:
(4 g NaOH / x mL) = (8 g NaOH / 100 mL)
Solving for x, we get:
x = (4 g NaOH / 8 g NaOH) * 100 mL
x = 50 mL
So, the final concentration of the diluted solution is 50 mL NaOH in 200 mL of solution, or 25% (m/v) NaOH.
To find the final concentration of the NaOH solution, we can use the concept of dilution. Dilution is a process in which a solution with a known concentration is mixed with a solvent (usually water) to decrease its concentration while maintaining the amount of solute.
In this case, we start with a 50 mL sample of 8% (m/v) NaOH solution. The 8% (m/v) concentration indicates that there are 8 grams of NaOH dissolved in 100 mL of solution. To calculate the initial amount of NaOH in the 50 mL sample, we can use the following equation:
Initial amount of NaOH = (Initial concentration) x (Initial volume)
= (8%) x (50 mL)
= 0.08 x 50 mL
= 4 grams
Now, we dilute this 50 mL NaOH sample to a final volume of 200 mL. The amount of NaOH remains constant in this process, so we have:
Final amount of NaOH = Initial amount of NaOH
= 4 grams
Next, we can find the new concentration of NaOH, using the equation:
Final concentration = (Final amount of NaOH) / (Final volume)
= 4 grams / 200 mL
= 0.02 g/mL
We need to convert this to a percentage concentration, so:
Final concentration = (0.02 g/mL) x 100%
= 2% (m/v)
Therefore, the final concentration of the NaOH solution after dilution is 2% (m/v).