Experiment #8: Limiting Reactant

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Experiment #8: Limiting Reactant

In chemical reactions, the significance of knowing the limiting reactant is high. In order to increase the percent yield of product, increasing the limiting reactant, possibly, is the most effective. In this experiment we were able to calculate limiting reactants from the reaction of CaCl2. 2H2O + K2C2O4.H2O(aq). As a group, we obtained our salt mixture of calcium chloride and potassium oxalate, and weighed the mixture. We were able to make an aqueous solution from the mixture and distilled water. We boiled and filtered off the solution, leaving the precipitate. Once the precipitate was dried overnight, it was weighed and the mass was measured. Then we calculated the moles of the precipitate.
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After cooling, the experimenters filtered the mixture using the filter paper and funnel
6. Experimenters left the filter paper to air dry overnight
7.The air dried filter paper was then placed on the weighing scale and results were recorded
In experiment A the results from the precipitation of CaC2O4 H2O from the salt mixture were obtained by weighing the items listed on Table 1 on a scale.
Table 1.
Mass of Beaker (g)
Mass of Beaker and Salt Mixture
Mass of Salt Mixture (g)
Mass of Filter Paper (g)
Mass of Filter Paper and CaC2O4 H2O (g)
Mass of Air-Dried CaC2O4 H2O (g)

In Experiment B the limiting reactant was determined to be CaCl2 when two drops of the test reagent 0.5 M CaCl2 was added to the supernatant liquid in test tube 1, and a precipitate formed. Since there was a reaction, there was C2O42- in excess and Ca2+ is the limiting reactant in the original salt mixture present in test tube 1 . This was further confirmed when two drops of the test reagent .05M K2C2O4 was added to the supernatant liquid in test tube 2. There was no precipitate because Ca2+ was not present since it was the limiting reactant and instead C2O42- was in excess.
Table 2.
Moles of CaC2O4 H2O precipitated (mol)
.0045 (mol)
Moles of limiting reactant in salt mixture (g)
CaCl2 .0004 (mol)
Mass of limiting reactant in salt mixture (g)
CaCl2 .4995 (grams)
Mass of excess reactant in salt mixture
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