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Writing a Lab Report. When performing a lab experiment we follow the scientific method. What is the scientific method? Purpose, Hypothesis, Procedure, Results, Conclusion. Scientific Method. What is the purpose? The purpose is why you are performing the experiment.
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When performing a lab experiment we follow the scientific method. • What is the scientific method? • Purpose, Hypothesis, Procedure, Results, Conclusion. Scientific Method
What is the purpose? • The purpose is why you are performing the experiment. • The purpose of this experiment is to determine a set of solubility rules and to determine when a precipitate will be formed by combining cations and anions together. Purpose
An educated guess about what will happen in the experiment. • In this experiment, it is hypothesized that a displacement reaction will occur when two ionic solutions are mixed together. This displacement reaction will result in the formation of a precipitate. Hypothesis
In this section all of the materials are listed in DETAIL. • 12x 250 ml beaker • 12x 50 ml graduated clyinder • 50 ml of OH-(aq) solution • 50 ml of Na+ (aq) solution Materials
In this section you provide a step-by-step, detailed account of how to perform the lab. • Remember, the idea behind a lab report is to be able to recreate the experiment. Procedure
Carefully pour 25ml of OH- (aq) solution into a clean 50 ml graduated cylinder. • Carefully pour 25ml of Na+ (aq) solution into a clean 50 ml graduated cylinder. • Pour the 25 ml of OH- (aq) solution from the graduated cylinder into a clean 250ml beaker. • Add the 25ml Na+ (aq) solution to 25ml OH- (aq) solution in the 250ml beaker. Procedure
Repeat procedure for each of the reactions as follows: • Ag+ (aq) + Cl- (aq)
The following data was collected and organized in the following table. • Let N.R. represent “no reaction” to indicate that there was no precipitate observed. • Let PPT. represent “precipitate” to indicate that a precipitate was observed. Data Collected
It was observed that a displacement reaction occurred when a cation was mixed with an anion. • However, a precipitate did not form for each reaction. • This can be explained by the properties of solubility. Results and Discussion
Some of the ions mixed are soluble with one another and will continue to exist in an aqueous solution. • Some ions are insoluble when mixed together and thus will form a solid, or a precipitate, in the beaker. • The solubility of an ion can be determined by determining solubility rules or by using a solubility chart to predict the reaction. Results and Discussion
In conclusion, the original hypothesis was not entirely correct. When cations are combined with anions a displacement reaction will occur. The result of the displacement reaction will depend on the solubility of each of the ions. Some ions are insoluble when combined with another specific ion, when these two ions combine they will form a precipitate. Other ions are soluble when combined and will not form a precipitate, but rather will continue to exist in an aqueous solution. Conclusion