Almansoori Lab 17

Data
1. Record your data for each of the trials in Table 2.
2. Record your reaction observations (Step 8) below:
A white powdery substance formed when the two reactants were mixed

Table 2: Reaction product data
Mass (g)
Example
Trial 1
Trial 2
Mass of CaCl2
1.00
2.00
3.00
Mass of K2CO3
2.5 g
2.50
2.50
Mass of filter paper
0.8 g
0.80
0.80
Mass of watch glass
38.5 g
38.5
38.5
Combined mass of product, filter paper, and watch glass
40.2 g
42.3
43.3
Mass of dry product
0.9 g
2.00
3.00

Calculations
1. Determine the limiting reagent for each trial. Show your calculations. (Hint: See the example in the Introduction.)
Example:
 

Trial 1:

Note: These should be about the same and either CaCl2 or K2CO3 can be the limiting reagent depending on their initial masses.
Trial 2:

Table 3: Comparison of theoretical and actual yields for CaCO3
Trial #
Limiting Reagent
Theoretical Yield of CaCO3
Actual Yield of CaCO3
% Yield
Trial 1

 
 
 
Trial 2
 
 
 
 
Trial 3
 
 
 
 

2. Calculate the theoretical yield of CaCO3 that could be produced by each trial and then fill in Table 3.
 

3. Find the percent yield each trial obtained for the CaCO3.
 

Pre-Lab Questions
1. A limiting reagent is one that is used up first out of the reagents that are used. This substance determines how much actual product is made
2. CaCl2: 7.15 g x 1 mol / 111.0 g = 0.06 mol CaCO3
K2CO3: 9.25 g x 1 mol / 138.2 g = 0.07 mol CaCO3
CaCl2 is limiting reagent
Theoretical yield = 0.06 mol CaCO3 x 100 = 6.40 g CaCO3
Percent yield = 6.15 g / 6.40 g = 96.1 %
Post-Lab Questions
1. In this first trial, I saw that there was less calcium carbonate that was produced.
2. The results were expected because less reactant was used in the first trial compared to the second trial.
3. Reducing the amount of CaCl2 used would still keep this substance as the limiting reagent and therefore the mass of CaCO3­ would be affected.