How would you prepare 2.5 L of a 0.05 M solution of iron (III) chloride using iron (III) chloride hexahydrate
Since 1 mol iron(III)chloride hexahydrate contains 1 mol iron(III) chloride, use the molar mass of the hexahydrate.
M x L = grams/molar mass
Solve for grams. In preparing the solution, BE SURE that you add water to a certain volume and not add a certain volume of water.
Post your work if you get stuck.
Moles iron (III) chloride hexahydrate
Moles = volume x concentration
2.5L (0.05M) = 0.125 moles
Then using number of moles
Mass required = number of moles x (RMM of iron (III) chloride hexahydrate)
0.125moles x 162.2g/mol = 20.27 grams
is this right?
Your answer is ok if you are weighing FeCl3 BUT the problem says to weigh FeCl3*6H2O. So, no, it isn't correct. I thought I said something in my response about using the molar mass of the hexahydrate.
hexahydrate: 270.3 g·mol−1
therefore would it be
0.125 moles x 270.3 g/mol = 33.78 grams?
Yes. Since the question asks how to prepare a solution of xxxxxx, it is important that you understand the difference between making the solution to volume and add a certain volume of water. For example, the directions would be thus:
Weigh 33.78 grams of FeCl3*6H2O, place in a 2.5 L volumetric flask, add some water to dissolve all of the iron compound, THEN add sufficient water to make to the mark in the volumetric flask. Notice that this is different from adding 33.78 g of the iron compound to a flask and adding 2.5 L H2O.
Hello, I have the answer to this question because I did everything empirically, not theoreticaly like all you people. Anyways, first I take a relatively exact amount of iron (III) chloride hexahydrate and by method of titration, I neutralize the iron (III) chloride with a NaOH solution. You people may not understand it so I'll just give you the answer.
It's 0.
35.2
33.8
I see that you have a different approach to preparing the solution of iron(III) chloride. While titration can be a valid method to determine the concentration of a solution, in this case, you can prepare the solution directly using the given information.
To prepare 2.5 L of a 0.05 M solution of iron(III) chloride using iron(III) chloride hexahydrate, you need to follow these steps:
1. Determine the moles of iron(III) chloride hexahydrate:
Moles = volume x concentration
Moles = 2.5 L x 0.05 M = 0.125 moles
2. Calculate the mass of iron(III) chloride hexahydrate needed:
Mass = moles x molar mass
Mass = 0.125 moles x 270.3 g/mol (molar mass of iron(III) chloride hexahydrate)
Mass = 33.79 grams (rounded to two decimal places)
So, to prepare the solution, you would weigh approximately 33.79 grams of iron(III) chloride hexahydrate, dissolve it in a container, and then transfer it to a 2.5 L volumetric flask. Finally, add water to dissolve all of the iron compound and fill the flask up to the mark.
Note: It's important to mention that this method assumes the molar mass and purity of the iron(III) chloride hexahydrate are known and accurate.