Reaction Outcome CER

Author's Note: In chemistry, we had to write a lot of CER's (claim data reasoning). This one was probably my best, and it is based off of an experiment we did, which I refer to as "the reaction outcome challenge".

      Atoms and mass are conserved during a chemical reaction. In the reaction outcome challenge lab, Potassium Chlorate (KClO3) was heated, turned into a liquid as the intermolecular bonds were weakened, and was continually heated until it turned until a solid as intramolecular bonds formed stronger than the intermolecular bonds, keeping the molecules packed tightly together. The new substance weighed 39.17% less than the original substance. At first, it seems impossible that the Law of Conservation of Matter wasn’t broken. But really the oxygen, that was in the substance and then wasn’t, did not actually disappear. Before the lab was conducted, the following measurements were made: the mass of the empty test tube- 21.64g, the mass of the test tube with the potassium chlorate- 24.12g, and the mass of the test tube with the manganese dioxide catalyst and potassium chlorate- 24.17g. So, the mass of the potassium chlorate was 2.48g, and after the substance melted and solidified again, it weighed 1.61g, or 39.17% less than the original substance. To prove it, 39.17% of the substance (the amount of oxygen) was multiplied by 2.48g, the total weight of the initial substance, to get 0.97g. 0.97g was then subtracted from the total substance to get 1.51 g. The oxygen left the test tube, and did not leave completely. Since 39% of the KClO3was oxygen, and during the process about 39% of the mass was lost, the oxygen only left the test tube and didn’t actually disappear.

      The release or absorption of energy from a chemical process depends on changes in bonding and interactions. According to the law of conservation of energy, energy can’t be destroyed or created; it can only change from one to another or be transferred from one object or substance to another. This indicates that energy can enter and be absorbed by substances or exit and be released from substances. The process of energy entering and being absorbed by a substance is endothermic, and the process of energy being released and exiting a substance is exothermic. During change number three of the endothermic and exothermic investigation lab, solid Ba(OH)2 and solid NH4SCN produced a liquid chemical along with ammonium. The reaction got very cold as the solid compounds liquified. It did not melt to become solid, but in fact energy was absorbed to break the bonds of the solids to become liquid. The energy had to come from somewhere, so it was taken from its surroundings, or the beaker. Therefore, this process was endothermic, as energy was absorbed. An example of energy being released, or an exothermic process can be found in change number four from the endothermic and exothermic investigation lab. Change number four was a spontaneous combustion of the purple solid potassium permanganate. Spontaneous combustion is the ignition and burning of a substance that occurs without using an external source of heat such as a match or burner. The potassium permanganate increased in energy; it released energy in the form of heat, creating a seemingly random fire.