post assessment

Moderators: Chem_Mod, Chem_Admin

Maggie Doan 1I
Posts: 61
Joined: Fri Sep 28, 2018 12:24 am

post assessment

Postby Maggie Doan 1I » Sat Oct 06, 2018 1:49 am

5.00 g of KMnO4 is dissolved in a 150.00 mL flask of water. If 20.00 mL of this solution is removed and placed in a new 2nd 250.00 mL flask and filled with water, what is the concentration of the solution in the 2nd flask? Molar Masses: K (39.10 g/mol), Mn (54.94 g/mol), O (16.00 g/mol)

Why do you use 20.00 mL as your Vintial when trying to find Mfinal?

Isabel Nakoud 4D
Posts: 101
Joined: Fri Sep 28, 2018 12:27 am

Re: post assessment

Postby Isabel Nakoud 4D » Sat Oct 06, 2018 9:51 am

5.00 g of KMnO4 is dissolved in a 150.00 mL flask of water. If 20.00 mL of this solution is removed and placed in a new 2nd 250.00 mL flask and filled with water, what is the concentration of the solution in the 2nd flask? Molar Masses: K (39.10 g/mol), Mn (54.94 g/mol), O (16.00 g/mol)

Why do you use 20.00 mL as your Vintial when trying to find Mfinal?


If you are confused because you believe that 150.00 mL should be the initial Volume, let me clarify that you use the 150.00 mL to find the initial Molarity of KMnO4. After you find the molarity, you have your solution. Then, a 20.00 mL sample of that solution is taken and it is diluted with the 250.00 mL (Final Volume). Therefore, you are trying to compare the initial Molarity to the final Molarity (which you are solving for), and so to do that you are comparing the initial Volume of 20.00 mL to 250.00 mL.

Hope this helps, if not, reply and I'll come back again to answer!


Return to “Molarity, Solutions, Dilutions”

Who is online

Users browsing this forum: No registered users and 1 guest