Solution Concentrations for FeSCN Equilibrium | Homework Problem

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SUMMARY

The discussion focuses on calculating the initial concentrations of Fe3+ and SCN- in various solutions, as well as the final concentration of FeSCN2+ in Solution #1A. The user initially miscalculated the concentrations by incorrectly converting units, specifically by multiplying molarity by liters instead of the appropriate volume in liters. The correct approach involves using the formula C1V1 = C2V2, where V2 should account for the total volume of the solution, including water.

PREREQUISITES
  • Understanding of molarity and concentration calculations
  • Familiarity with the formula C1V1 = C2V2
  • Basic knowledge of chemical equilibrium concepts
  • Ability to perform unit conversions accurately
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  • Review the principles of chemical equilibrium and concentration calculations
  • Practice using the formula C1V1 = C2V2 with different scenarios
  • Learn about the formation of complex ions, specifically FeSCN2+
  • Explore unit conversion techniques in chemistry for accurate calculations
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Chemistry students, particularly those studying equilibrium reactions and solution concentrations, as well as educators looking for examples of common calculation errors in chemical 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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