Solution Concentrations for FeSCN Equilibrium | Homework Problem

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Discussion Overview

The discussion revolves around a homework problem related to calculating solution concentrations for an equilibrium involving FeSCN. Participants are addressing specific questions regarding initial concentrations of Fe3+ and SCN1- in various solutions, as well as the final concentration of FeSCN2+ in one of the solutions. The focus is on applying relevant equations and understanding the relationships between concentration, volume, and dilution.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant attempts to calculate the initial Fe3+ concentration by multiplying the concentration by the volume in liters but finds the result incorrect.
  • The same participant applies the same method to calculate the initial SCN1- concentrations but also receives incorrect feedback.
  • Another participant suggests using the formula C1V1=C2V2 and questions what value should be used for V2, considering the differing volumes of water in each solution.
  • A later reply indicates that the initial participant has resolved their confusion regarding the calculations.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the correct approach for calculating the concentrations, as there are differing interpretations of the problem and methods used. The discussion remains unresolved regarding the specific calculations for parts a and b.

Contextual Notes

Participants express uncertainty about the correct application of concentration and volume relationships, particularly in relation to the differing volumes of water in the solutions.

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Homework Statement



a. the initial Fe3+ concentration of all of the solutions?
b. the initial SCN1- concentrations of Solutions #1A thru #5A?
c. the final concentration of FeSCN2+ in Solution #1A?

Homework Equations


The first column is the solution number, the second column is the volume of .100M Fe^3+, the third column is the volume of 5.00e-4M SCN^1-, the fourth column is the volume of water, and the fifth column is the total volume. All volumes are in units of mL.

1A 1.00 1.00 4.00 6.00
2A 1.00 1.50 3.50 6.00
3A 1.00 2.00 3.00 6.00
4A 1.00 2.50 2.50 6.00
5A 1.00 3.00 2.00 6.00

The Attempt at a Solution



For part a., I tried multiplying the given .100M by .001L to get .000100M. This, however, is incorrect according to my online assignment.

For part b., I did the same thing but with the SCN^1-. I multiplied the 5.00e-4M by the volume in mL. So for solution #1A, I did (5.00e-4M)*(.001L) and got .000000500M. This too is incorrect on both in both respects.

Part c is the same deal.

If anyone could help me with part a and maybe one from part b, I could do the rest. Any help is much appreciated.
 
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0.100M*0.001L is not 0.0001M, pay attention to units.

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methods
 
Okay. I'll rephrase what I think I should do. I think I need to use the formula C1V1=C2V2. Given the concentration of Fe^3+ and the volume of Fe^3+, what should I use for V2. Should it be the volume of Fe^3+ plus the volume of water. If that is the case they wouldn't all be the same since the volume of water differs for solutions 1-5, however, the question asks for one number.
 
Figured it out...nevermind
 

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