Rosa E, Bijan A, Briana M, Eduardo C, Sam B
Title: Endothermic and Exothermic Reactions
Purpose: The purpose of this experiment is to observe endothermic and exothermic reactions with sodium bicarbonate, copper sulfate, magnesium metals and citric acid.
Background: Endothermic and Exothermic reactions relate to sustainability because they occur constantly in energy production. For example in water cooled nuclear reactors, heat from the reactors core is absorbed by the water and becomes steam which is an endothermic reaction. And inversely when the steam in the nuclear reactor condenses back into its liquid state energy is released causing an exothermic reaction.
Procedure: Endothermic
1. Get citric acid and sodium bicarbonate
2. Measure 15 grams of sodium bicarbonate on a scale (remember to zero out plastic cup)
3. Measure out 25 mL of citric acid into a beaker
4. Drop in temperature probe, hit start (make sure to get initial temp)
5. Mix solutions (under hood) and stir until reaction is complete
6. Record the changes in temperature
In the second section of this experiment 25mL of citric acid and 15g of sodium bicarbonate will be combined in a 600mL beaker, and the change in temperature will be monitored. It is expected that the temperature will drop showing an example of an endothermic reaction.
Exothermic
1. Get copper sulfate and Magnesium metal strips
2. Measure out 5 grams of magnesium metal (zero out plastic cup)
3. Measure 100 mL of copper sulfate and pour into beaker
4. Insert temperature probe, (get initial temp)
5. Mix solutions and stir until reaction is complete
6. Record changes in temperature
– The First part of this experiment is to combine of 5g of magnesium and 100mL of Copper Sulfate in a 600mL beaker and monitor the change in temperature. The temperature is expected to rise in this portion of the experiment showing us an exothermic reaction
Data: For the first part of the experiment, the initial temperature was at 21.6 degrees Celsius, after the reaction of copper sulfate and magnesium metal strips the final temperature progressed to 27.4 degrees Celsius. The change in temperature was 5.8 degrees Celsius which indicated an exothermic reaction as predicted.
The second part of this experiment began with an initial temperature of 21.5 degrees Celsius. After the mixture of citric acid and sodium bicarbonate the final temperature was 12.9 degrees Celsius with a change in temperature of -8.6 degrees Celsius. This displays an endothermic reaction.
Analysis: The data collected in this lab illustrates the properties of Endothermic and Exothermic chemical reactions. They are fundamental principles of chemistry and play a vital role in life, from energy production to combustion engines and more.
Discussion: On the day of presentations all of the groups presented their power points. Our presentation went well, all members of the group presenting a slide. An aspect that was weak in our presentation was in relating the experiment to sustainability. Two groups from our class arrived to present, but only one from the other class, so we presented our presentation to one member of the group from the other class. The other group from our class presented to the other person. We intended to have the other group do the experiment on their own and be there as guiding influences. Since we were only doing the experiment with one person that would have been rude. Instead we all worked together to do the experiment, and made sure that the person from the other group was involved in the interesting parts of the reaction. Over all the presentation went well. The experiments behaved in the ways they were expected to. The person we were presenting to handled the experiment well. Safety goggles and gloves were worn, and a fume hood was used as a precaution.
More on Endothermic and exothermic reactions:
Photosynthesis is an example of an endothermic chemical reaction. In this process, plants use the energy from the sun to convert carbon dioxide and water into glucose and oxygen.
While combustion is an example of an 
exothermic reaction.
Here are links to some videos on endothermic and exothermic reactions:
http://www.youtube.com/watch?v=XYRCXoFWPZw a basic example
http://www.youtube.com/watch?v=cBy4Q6A8Hfw a more academic example