Percent Yield Lab

Name:

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Lab

?Partners:

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Percent Yield of a Precipitation Reaction Lab Activity

In this lab, you will be reacting solutions of silver nitrate and ammonium chloride. If all goes as

planned, your reaction should undergo a very noticeable change and should produce a precipitate.

After filtering your solution, you will be able to obtain the mass of the precipitate and calculate the

percent yield for the precipitate.

Details about the chemicals being used:

Silver nitrate: Purchased in solution form. The bottle reads that the solution has a concentration of

0.100 M. Will stain both hands and clothes. If you end up with silver nitrate on your hands, rinse

immediately. Do not ingest.

Ammonium chloride: Prepared by Mr. Hammel for your lab. To prepare the solution, 5.35g of

ammonium chloride powder was added to 500 mL of water. Rinse hands immediately if contact with

ammonium chloride solution should occur. Do not ingest.

Procedure:

Note: Throughout this process, record all the values that you used. If the procedure says to add

25.0mL but you add 24.8mL instead, that is fine, but write this down on the next page.

Day 1:

1. Thoroughly rinse and clean all of the glassware you are using with water. If foreign chemicals exist in

your glassware, it can cause a different reaction to occur than the one you want.

2. Ensure your pipette is clean and dry! If you put it into the silver nitrate and it is not clean, it can

contaminate the entire sample. Using a pipette, obtain 25.0 mL of silver nitrate. Place this in your

small beaker (~150mL). This will require you to fill the pipette more than once.

3. Rinse your pipette a minimum of three times with water. Again, ensure that it is dry and clean.

4. Using a pipette that has been thoroughly cleaned, obtain 20.0 mL of ammonium chloride. Add this to

your sample.

5. Stir your sample using a stir rod (glass end). Rinse the stir rod off into the beaker using water. You do

not want to have part of your precipitate leave the sample on your stir rod.

6. Obtain the mass of the filter paper using a balance.

7. Add the filter paper to the funnel (Mr. Hammel will show you how at the beginning of the lab).

8. Pour your entire solution through the filter paper.

9. Rinse your beaker with a small amount of water (approximately 10mL). Pour this water through the

filter paper as well. Repeat this step twice, or as many times as necessary to get all of the precipitate

from the beaker to the filter paper.

10. Have one member (or everyone) of your group come back at lunch and remove the filter paper from

your funnel. Let sit on the side bench overnight to fully dry. Ensure to set your filter paper on a labeled

piece of a paper.

Day 2:

1. Obtain the mass of your filter paper and precipitate. Record in the data section.

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Name:

?______________________________

?

Lab

?Partners:

?______________________________________

?

?

Required Data to be Recorded Throughout the Lab

- Volume of silver nitrate used: ___________ mL

- Concentration of silver nitrate used: __________ mol/L

- Volume of ammonium chloride used: ___________ mL

- Concentration of ammonium chloride used: ___________ mol/L (calculation must be shown below)

- Mass of filter paper before using: __________ g

- Mass of filter paper and precipitate after drying: __________ g

- Mass of only the precipitate: _____________ g

Analysis

**This section must be completed individually. If I feel that you have copied someone else¡¯s analysis, I

will be asking you to complete another one. If you are unable to complete it, your analysis will receive a

grade of 0%.**

1. Using the correct formulas and correct units, calculate the concentration of the ammonium chloride used as a

reactant.

2. Provide the balanced chemical reaction for the reaction that occurred in this lab. Be sure to provide the

correct states of matter. Check your solubility chart if you need to for the states of the products.

3. Provide both the chemical formula and the proper name for the precipitate formed in this reaction.

4. Which of the two reactants was your limiting reagent? Which of the two reactants was the excess reagent?

Explain in words how you determined which is which.

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Name:

?______________________________

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Lab

?Partners:

?______________________________________

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5. Using your limiting reagent and your balanced chemical reaction, calculate the theoretical yield of the

precipitate.

6. Calculate the percent yield of your reaction using the experimental yield, the theoretical yield, and the

following formula:

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% ?????? = ?

?100%

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7. Comment on your percent yield. Questions to consider: Does it seem reasonable? Why or why not? What

factors may have influenced your value? What would you change next time?

8. After filtering your solution, you were left with a precipitate in the filter paper and a solution in your

Erlenmeyer flask. What do you think the solution in the Erlenmeyer flask was? Explain

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