a 111.4mg ore sample containing iro with acid , filtered and diluted to 200.0ml in volumetric flask. a 1000ml aliquot is transferred to a 100.ooml volumetric flask containing hrdroxylamine hydrochloride, sodium acetate and 1,10- phenanthroline and diluted to the mark . the resulting orange-red solution hadan absorbance of 0.486 at 508nm in a cm cell . if the molar absorptivity of the iron-phenanthroline complex at this wavelength is 1.86*10^3 l/molcm , determine the percentage of the iron in the ore sample?
You need to proof what you post. How do you transfer a 1000 mL aliquot OUT of a 200.0 mL volumetric flask INTO a 100.00 mL volumetric flask containing......? I would like to see this done.
By the way, you don't list the length of the cell.
To determine the percentage of iron in the ore sample, we need to calculate the concentration of iron ions in the resulting orange-red solution and then convert it to a percentage.
Let's break down the steps:
1. Calculate the concentration of iron ions in the orange-red solution:
The absorbance (A) of a solution is related to the concentration (C), the path length (l), and the molar absorptivity (ε) through the Beer-Lambert Law: A = ε * l * C.
Given:
- Absorbance (A): 0.486
- Path length (l): 1 cm
- Molar absorptivity (ε): 1.86 x 10^3 L/molcm
Rearranging the equation, we have: C = A / (ε * l)
Plugging in the values: C = 0.486 / (1.86 x 10^3 * 1)
Calculate C.
2. Calculate the concentration of iron ions in the original 1000 ml aliquot:
Since we transferred 1000 ml of the solution to a 100.0 ml volumetric flask, the concentration will be diluted by a factor of (100/1000) = 0.1.
Multiply the concentration obtained in step 1 by the dilution factor to obtain the concentration of iron in the 1000 ml aliquot.
3. Calculate the concentration of iron in the original 111.4 mg ore sample:
Now we need to convert the concentration obtained in step 2 to moles of iron. To do this, divide the mass (in grams) of the ore sample by the molar mass of iron (55.845 g/mol). This will give us the number of moles of iron.
Then, divide the moles of iron by the volume of the ore sample in liters (200.0 ml = 0.200 L).
Calculate the concentration of iron in the ore sample.
4. Calculate the percentage of iron in the ore sample:
Finally, to determine the percentage of iron, divide the concentration of iron in the ore sample by the concentration of the original ore sample and multiply by 100.
Calculate the percentage of iron in the ore sample.
Please note that the calculations involve multiple steps and units conversion, so it's important to keep track of units and perform the necessary conversions.