In this experiment we combined sulfuric acid and aqueous barium chloride to produce a precipitate, barium sulfate and hydrochloric acid. The precipitation was isolated by filtration and theoretical yield was calculated. We predicted the limiting reactant and verified our hypothesis in the lab.
II. RESULT ANALYSIS
DATA TABLE
Table 1
Trial 1 Trial 2
Table 2.
- DISCUSSION
In this experiment we combined sulfuric acid and aquenous barium chloride to produce a precipitate, barium sulfate, and hydrochloric acid. Our assigned volumes of 0.20 M BaCl were 5mL and 30mL.
H SO + BaCl → BaSO + 2HCl
After finishing the experiment we calculate the mass of BaSO that we isolated. The results of the two trials were:
0.7g when we used 30 mL of BaCl and
0.017g when we used 5 mL of BaCl.
- We calculated the theoretical yield of BaSO using our assigned volume.
We know that:
Molarity= # of moles/ # of liters, so:
Trial 1.
To find the number of moles we use the molarity formula:
30mL= 0.03L
0.2M = #of moles/ 0.03L = 0.006 moles of BaCl
We know from the chemical formula that there is a 1/1 mole ratio between BaCl and BaSO, and that AW of 1 mol of BaSO = 233.404, so we transform moles to grams:
0.006 x (233.404g) =1.400g BaSO
Trial 2.
To find the no. of moles we used the molarity formula:
5.0 mL = 0.005L
0.2M = # of moles / 0.005 = 0.001 moles of BaCl
AW of 1 mole of BaSO = 233.404g, so we transform moles to grams:
0.001 x (233.404g) = 0.233g BaSO
- After determining the theoretical yield we calculated the percent yield of BaSO:
Trial 1.
The actual mass of BaSO isolated in our experiment was 0.7 g
We found our theoretical yield to be 1.400g of BaSO, so
The percent yield = 0.7g/ 1.400g x 100
= 50%
Trial 2.
The actual mass of BaSO isolated was 0.17g.
We found our theoretical yield to be 0.233g of BaSO, so
The percent yield = 0.17g/ 0.233g x 100
= 73%
After we calculated the mass of barium sulfate that we isolated and added our results (averaged with the group that used the same volume of barium chloride) to Table 2, for the class graph of “ mass of barium sulfate made vs. volume of barium chloride used”.
We averaged our results and drew a graph.
The fact that the graph rises means that BaCl is the limiting reactant so its amount determines the product of BaSO. If the graph leveled off than BaCl would be in excess.
III COMMENTS
In this particular experiment we learned how to write and balance chemical equation. Further more we performed calculations involving limiting reactants, theoretical yield and percent yield.