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Stoichiometry: An Analysis Of Limiting Reactants

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Reflection on the lesson: Stoichiometry, an introduction to limiting reactants.

The first lesson on limiting reactants was an introduction to the concept. For this lesson, molecule and moles were used as a qualitative and quantitative analysis of limiting reactants. I feel this lesson went well and the objective of understanding limiting reagents through balance equations and moles was met using the given the standard of 80% of students understanding the lesson at 80% comprehension.
The lesson started with a real world analogy of sandwich making and what you need to make one sandwich. Adding part of the ingredients was used to show what would stop me from making another “exact” sandwich. The ingredients we were lacking were the limiting …show more content…

Small groups where used as a formative assessment with a check list. As I walked around, some of the students were confused as to how the simulator worked. I helped them through it. Although this was a problem at the beginning, the students liked the visual and learned from it. The way the simulator related the visual to an equation was also an issue with the students. I did explain this on the board before the simulator and most grasp the concept of reactants products and leftovers. This was a change I made from the first class and the explanation on the board seemed to help 80% of the students in the second chemistry class (only one group of 4 was confused). While checking in with each group, I notice by the end of the simulation all but three students understood the limiting reactant concept on a visual/molecular level (92%). One students was not doing enough of the work for me to determine if he grasp the concept. The two students who were struggling were restarted from the beginning where two molecules react with two molecules. Both students then grasped the concept and I watched for comprehension with the next problem. Both understood the next problem. I believe when these students were working with their groups, they were moved too quickly to the second problem. Without grasping the concept from the first question, they were …show more content…

To finish the lab, students weighed the dried samples from a precipitation reaction. The calculations were then finished. Some students did not get to the calculations today and will have to finish tomorrow. This lab can tie directly into limiting reactants, but I am seeing a disconnect between lab analysis and the chemistry concepts that we are working on. Even though the calculations are directly related to the topics we are covering, the students work through the steps without realizing the connection. This is true with the top students as well as the lower achieving students. I think the step by step instruction may be limiting this connection and stifling the student’s ability to analyze the calculations. When I teach limiting reagent calculations in the next few days, I will use the lab reaction as a model for the calculation. To further connect the lab calculations with the lesson, I will use data from a student’s lab as part of the modeling to show the direct connection. I hope this will

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