You extract the iron from a tablet and dilute that to 600.0 ml in a volumetric flask. You transfer 0.600 ml of this solution to a 75.0 ml volumetric flask and dilute this to volume. When you measure the concentration of this solution, you find that it is 3.78 mg Fe/L (ppm). What is the Fe of the Sample Stock Solution, in mg/L?
3.75 mg/L is the concn of the material in the 75 mL volumetric flask. Therefore, the concn of the material in the 0.6 mL is
3.75 x 75/0.6 = ? and that is the concn of the material in the 600 mL flask (and the sample).
To solve this problem, we need to follow a series of steps to calculate the concentration of iron in the sample stock solution.
Step 1: Calculate the concentration of the diluted solution.
The concentration of the diluted solution can be calculated using the formula:
C1V1 = C2V2
Where:
C1 = concentration of the stock solution (unknown)
V1 = volume of the stock solution (0.600 ml)
C2 = concentration of the diluted solution (3.78 mg Fe/L or ppm)
V2 = volume of the diluted solution (75.0 ml)
Substituting the given values into the equation:
C1 * 0.600 ml = 3.78 mg Fe/L * 75.0 ml
Step 2: Convert the volume of the diluted solution to liters.
Since the concentration is given in mg Fe/L, we need to convert the volume from milliliters to liters:
75.0 ml = 75.0 ml * (1 L / 1000 ml)
= 0.075 L
Substituting this value into the equation:
C1 * 0.600 ml = 3.78 mg Fe/L * 0.075 L
Step 3: Solve for C1 (concentration of the stock solution).
C1 = (3.78 mg Fe/L * 0.075 L) / 0.600 ml
Step 4: Simplify the equation.
C1 = 0.47325 mg Fe / 0.600 ml
Step 5: Convert the concentration to mg/L.
To convert from mg Fe/0.600 ml to mg/L, we need to consider that 0.600 ml is equivalent to 0.600 L:
C1 = (0.47325 mg Fe / 0.600 ml) * (1000 ml / 1 L)
= 788.75 mg Fe / L
Therefore, the concentration of iron in the sample stock solution is 788.75 mg Fe/L.