From your balanced equation what is the theoretical yield of your product? One of the most common ancient medicines for pain, fever, and inflammation came as a byproduct of the willow tree. Then learn how to figure out the actual yield, theoretical yield and percent yield of the experiment. Then, while holding the filter paper in place and open, slowly pour the content of the beaker into the filter paperlined funnel. I would suggest using a funnel, where the bottom can be plugged and unplugged, so that you can get everything off the side of the funnel without losing anything. Do not have students heat a sample of sodium carbonate to dryness constant mass because it begins to decompose at 400°C.
Experiment and Observation: The first step in this experiment was to use the scale to measure out 1. The only way was to read it to the nearest tenth, so it can be measured. When the filter paper and the precipitated calcium carbonate are completely dry weigh them, subtract the original weight of the empty filter paper, and record the net weight of the calcium carbonate. When both solutions are mixed, the paper filter that was provided with the lab must be weighed and recorded. D A perfect percent yield would be 100%.
If your measure value was bigger, then the percent difference will be positive. After the reaction is completed and the precipitate has formed, we need to filter and dry the precipitate before we can weigh it. You may find it helpful to use a ruler. Excess barium nitrate is added, causing the sulfate ions to precipitate completely as barium sulfate. A substance will precipitate when solution conditions are such that its concentration exceeds its solubility.
Secondly, the experiment accurately measures the reactants and products of a reaction. Based on your results, describe your degree of accuracy and suggest possible sources of error. Use only distilled water since tap water may have impurities that interfere with the experiment. This lab has been designed so that students do not need to know how to calculate the number of moles of calcium chloride. Be careful to observe what happens. Be careful to not let the solution overflow the level of the filter paper while pouring.
Consider, for example, that you will need to know the mass of containers you use for weighing. Find the moles of each of the ions 8. Do not allow it to spill over. Add 25 mL of distilled water and stir to form the calcium chloride solution. Determine what reaction takes place 2. Add 25 mL of distilled water and stir to form the calcium chloride solution.
You end up with 2 possible scenarios for this reaction. How would that compare to the amount of calcium carbonate you calculated would result from the reaction? Because not all aqueous reactions form precipitates, one must consult the solubility rules before determining the state of the products and writing a net ionic equation. Some of the error could be the amount of distilled water because reading the amount in a graduated cylinder is hard to see if you are exactly below or above 25 ml. Stoichiometry of a Precipitation Reaction October 1, 2013 Chem 131A-011 Partner: Purpose: This lab exercise combines the study of a precipitation reaction with stoichiometry. Liquid which overflows can no longer be filtered.
Step 8: Determine the actual yield and percent yield. Then, that solution was poured into the 100 mL beaker and it formed a precipitate calcium carbonate instantly with the calcium chloride solution. Using distilled water reduces the chance that any excess carbonate ions may be present. Also, do not exceed the capacity of the flask: it can hold a maximum of about 250 mL. It is also the primary component of the shells of marine mollusks and is a very common source of calcium in calcium supplement pills. If we assume that after drying we have 1. Once all the liquid has drained from the funnel, lay the filter paper containing the precipitate on folded layers of paper towels and set it somewhere to air-dry.
This gives a low percentage yield of. Version 42-0201-00-02 Lab Report Assistant This document is not meant to be a substitute for a formal laboratory report. Next, I had to figure out the amount of the second reactant, so that it can be added to the solution. Abstract: The purpose of the lab, Stoichiometry of a Precipitation Reaction, is to be able to calculate the amount of a second reactant we need to react with the reactant one. Then, pour the content of the beaker into the filter paper-lined funnel carefully.