Exothermic Reaction Lab

The purpose of this lab was to use a calorimeter to learn when energy is being released or absorbed in a chemical reaction. My lab partner and I had to determine the heat exchanged when solid magnesium hydroxide is mixed with solid citric acid, using a coffee cup calorimeter. Given that citric acid is soluble in water is the property that makes this reaction possible. The first law of thermodynamics and Hess’s law are also present within this experiment. Knowing the difference between endothermic and exothermic reactions is also relevant. If the temperature goes down when energy is put in this means that the bonds are breaking. If the temperature goes up then bonds have formed .There were also many formulas needed for this experiment. Those
Hess’s law states that the amount of energy depends on the states of the reactants and the state of the products but not the steps that happen between. This allows us to calculate the values needed by piecing together the rest of the equation without having a direct calculation to convert to the final value needed. In the first part of the experiment the solution started to lose some heat when added to the water, this happens because the solution was dissolving in the water which caused the temperature to drop. This is opposed to part two of the reaction where the temperature rose. The temperature rose because the bonds within the solution were beginning to form, and as more of the bonds form, the more the temperature rises. A very similar result can be seen in the second half of the experiment when in part three the solution when added to water slowing began to drop in temperature until it plateaued. In part four when the Magnesium Hydroxide was added to the solution the bonds once again began for form which made the temperature rise once again. The law that we used to combine the Hvalues was Hess’s law. Hess’s law allowed us to obtain the values for Hwithout having to calculate them directly. There are a few assumptions that people make when doing simple calorimeter experiments. One of those assumptions is that no heat will be lost to the environment when
This topic relates back to Chemistry 221 because we learned about Hess’s law. Hess’s law was used a lot within this experiment as there was no direct way to calculate the values needed to get to the solution for the experiment. Calorimetry has many different practical reasons in the real world. One of which can be applied to food science. Calorimetry can be used in food science to find the best possible conservation method to help prevent food from spoiling. Once principle of green chemistry that is applied to this experiment is principle number 3. This experiment represents principle 3 because the substances that were used are substances that are commonly used in many household products. While they may not necessarily be fit for human consumption they are not entirely harmful to human. These are some of the more mild substances that can be used in a reaction to reduce the risk to human