Stoichometry Lab

Jeff Chemistry-Mr. Meuret Stoichometry Lab Purpose: The purpose of this lab is to perform a chemical reaction and to have a percent yield of above 95%.

That is to ensure a job at a major multi-national cosmetics corporation. Equipment: Materials: 1. 2 Beakers 1. Na2CO3 2. Stirring Rod 2.

Deionized water 3. Ring stand 3. CaCl2 4. Iron ring 5. Pipestem triangle 6. Funnel 7.

Filter 8. Flask Procedures: Day 1 1. Put your beaker on the balance and rezero it. Then add about 1 g of Na2CO3 and record the mass.

Remove the beaker and then add about 25 ml of deionized water. Then mix the substances with a stirring rod. 2. Perform step one again only this time add about 1 g of CaCl2. 3. Mix the contents of the two beakers after they have both thoroughly dissolved.

4. Set up the filtering system of a ring stand, iron ring, pipe stem triangle, and funnel. Then obtain a piece of filter paper and weigh it. 5. Form a cone with the filter paper and place it in the funnel.

Place the flask under the funnel to catch the liquid coming out.Pour the mixtures into the filter paper, and rinse the beaker with deionized water to clear it of all of the mixture. 6. Get another beaker, label it, then weigh it.

7. After the mixture has been filtered, pull the filter paper out. Place it in the labeled beaker from the last step, then place it in the tub to dry. Day 2 8. Weigh your beaker, and then dispose of the filter paper that contains the product.

Data: |Item/Mass | | |Sodium Carbonate |1. 1 g | |Calcium Chloride |1. 01 g | |Filter Paper |1. 69 g | |Mass of Empty Beaker |45. 98 g | |Mass of Beaker+Paper+Product |48.

2 g | Calculations: 1. Determine the limiting reagent in this reaction. 2. What is the mass of calcium carbonate that was produced? 3.

How much mass of calcium carbonate should have been produced. 4. Calculate the percent yield of calcium carbonate. 5.

What is your percent error? 6. If the law of conservation of mass were truly observed, what mass of sodium chloride would have been produced? Questions: 1. Interpret your data. Did you get your results within a 5% error?Would you expect to receive a call back for the job? Why or why not? No, we didn’t get within a 5% error and we probably won’t get the job. That’s because our percent error was too high, and they wouldn’t want someone who made a lot of mistakes in the lab. 2.

What are 3 things you would do to increase your percent yield for this lab? First, you could be more careful during the filtration process to ensure that all the products are captured. Second, you have to ensure that all measurements are correct.Lastly, ensure that none of the products are lost during the final phase of drying as the powdery calcium carbonate might get blown away. 3. Why do think this company required such a high percent yield for its production? Is this a reasonable expectation for a corporation to expect of its employees? Why or why not? The company requires a high percent yield because during an actual chemical reaction that your are controlling for the lab, they would want you to come up with as much product as you can, so as to not waste anything and waste company money.So yes this is a reasonable expectation.

4. Pharmaceutical companies have an intense interest in developing new drugs. It may take Abbot Labs 10 years to develop a drug treating a specific condition. Would you expect the company to charge more for the drug produced at 75% yield or 60% yield? Explain your answer. They would charge more for the drug produced at 60% yield.

That’s because compared to a drug produced at 75%, the 60% would require more reactant to get an equal amount of the wanted product. Thus, it would be reasonable to sell it at a higher price.Conclusion: In this lab, we were applying for a job at a cosmetics corporation and we had to come up with a percent yield of higher than 95% to get the job. We mixed two aqueous solutions of sodium carbonate and calcium chloride to produce an aqueous sodium chloride and solid calcium carbonate.

Then we filtered out the calcium carbonate to dry and later from that we calculated our percent yield. In the end, we got a percent yield of 93%, so we probably won’t be getting the job. This percent yield might have been caused by several sources of error.First, during the filtration some of the product might have been left in the beaker and so remained unfiltered, or some passed right through the filter paper or over and thus wasn’t trapped on the paper. One major source of error that definitely occurred was that either the wind or someone knocked over our sample or product, and most of our calcium carbonate spilled all over the inside of the film hood.

Thus, while we attempted to save most of the product, a substantial amount was still lost thus reducing percent yield drastically. A final source of error might have simply been a mistake in the weighing of products.