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11 Dec 2019

I know its a lot of questions but anything helps! please help me im so lost!

1. Using the Beer’s law equation, A=εbc, where A - the unit-less absorbance, c - the molarity of the solution, and b - the path length in centimeters, find the units for the molar extinction coefficient, ε. Show your work. Don’t include numbers. (10 pts)

2. Given the following data for a colored solution, find the concentration of the unknown sample given. You will need to print a graph of absorbance vs. concentration as discussed in the experiment to do this. This cannot be done by hand for credit. Please remember to include the graph with your prelab and label each axis. A title should be given to all graphs. (10 pts)

Trial

Concentration,

(moles/liter)

Absorbance

(unit-less values)

1

0.080

0.399

2

0.16

0.715

3

0.24

0.950

4

0.32

1.136

5

0.40

1.429

Unknown Solution A

X

1.337

The concentration of unknown solution A is (moles/liter) ________________________

Show your calculation with units here:

3. Determine the total amount of the stock solution you will need for this experiment. Record that volume here and then in the procedure where there’s a blank for it: ________________________________mL of stock solution is needed for this experiment. (10 pts)

4. This multiple part question deals with concentrations.(10 pts)

A) What is the final concentration of iron(III) sulfate made if 17.804 grams of the solid is added to a 100.00 mL volumetric flask and then distilled water is added to the graduation. Assume the solid is anhydrous iron sulfate.

B) What is the concentration of sulfate ion in the solution?

C) What is the concentration of Fe3+ in the solution? Show your work.

5. You need 0.5000 M copper(II) sulfate solution for this experiment. Remember that copper(II) sulfate exists as a pentahydrate. (10 pts)

A) What is a hydrate?

B) What is the formula for copper (II) sulfate pentahydrate? What is the formula mass of this compound?

C) How would you, exactly, make 50.00 mL of a 0.515 M copper (II) sulfate solution?

D) Tell the exact mass of the solid needed.

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