Chemistry Lab Handout 16   "Limiting Reactant"

Your Name:    ___________________________________ Role:______________

Lab Partners: ________________Role:_____   ________________Role:_____

Problem:  How do you determine the limiting reactant in a chemical

          reaction?

Hypothesis:   _______________________________________________________

     _________________________________________________________________

     _________________________________________________________________

Materials:                   two 250 mL beakers 100 mL grad. cylinder
     distilled water         massing paper      scoopula
     balance            Sodium Phosphate Dodecahydrate
     stirring rod       Barium Chloride Dihydrate
     filter paper       funnel             80°C oven

Caution:

Procedure:
1. Pour 75 mL of distilled water into a clean 250 mL beaker using a
     100 mL graduated cylinder.
2. Place a small piece of paper on a balance and find its mass. Add
     0.800 grams to the reading on the balance.
3. Using a scoopula, place Sodium Phosphate Dodecahydrate on the piece
     of paper until you reach the balancing point.
4. Add the Sodium Phosphate Dodecahydrate to the distilled water. Stir
     until dissolved.
5. Using the paper on the balance again, set the balance to read
     0.700 g above the mass of the piece of paper.
6. Using a scoopula, place Barium Chloride Dihydrate on the piece of
     paper until you reach the balancing point.
7. Add the Barium Chloride Dihydrate to the Sodium Phosphate
     Dodecahydrate solution. Stir for about three minutes so the
     reaction goes to completion.
8. Obtain a piece of filter paper and find its mass to the nearest
     0.001 g. Record this on the data table.
9. Fold the piece of filter paper into quarters and place it in a
     funnel. Place the funnel into a second beaker.
10. Filter the solution through the filter paper so you capture all of
     the precipitate on the filter paper.
11. Pour 10 mL of distilled water into the original 250 mL beaker and
     swirl this around.
12. Pour the distilled water into the funnel. Repeat as necessary to
     transfer any remaining chunks of precipitate to the filter paper.
13. Remove the piece of filter paper from the funnel and place it on a
     paper towel.
14. Place the piece of filter paper into a 80°C oven.
15. After all of the water has evaporated away, find the mass of the
     filter paper and precipitate. Calculate the mass of the
     precipitate.

Observations:

Description of the reaction between Sodium Phosphate Dodecahydrate and Barium Chloride Dihydrate:

_______________________________________________________________________

_______________________________________________________________________

Data:

initial mass of filter paper:
mass of filter paper and precipitate:
mass of precipitate:

Diagram:

 

 

 

 

 

 

Conclusion:   _______________________________________________________

     _________________________________________________________________

     _________________________________________________________________

Questions:   

1. Write the balanced chemical reaction for this lab.
2. What type of reaction was it? __________________________________
3. Determine the mass of Barium Phosphate that would be predicted
     using 0.800 g of Sodium Phosphate Dodecahydrate.
4. Determine the mass of Barium Phosphate that would be predicted
     using 0.700 g of Barium Chloride Dihydrate.
5. Which of the reactants was limiting? _____________________________
6. What was the percent yield of the Barium Phosphate that was
     produced?
7. Explain what improvements you would make in this procedure to
     minimize waste of reactants and increase your percent yield.