Chemistry: Magnesium Hydroxide And Citric Acid

Introduction: In this lab, I determined the amount of heat exchanged in four different chemical reactions only using two different compounds and water. The two compounds used were Magnesium Hydroxide and Citric Acid. Both compounds were in there solid states in powder form. Magnesium Hydroxide was mixed with water and the change in heat was measured using a thermometer. The next reaction combined citric acid and magnesium hydroxide in water. The change in heat was measured as well. For the third reaction citric acid was placed in water to measure the change in heat. In the last reaction, citric acid was combined with water. The heat exchanged was again measured. It is obvious we were studying the calorimetry of each reaction. We used a calorimeter

The first law of thermodynamics simply states that heat is a form of energy and heat energy cannot be created nor destroyed. In this lab we were measuring the change in temperature and how it affected the enthalpy of the reaction. During this reaction the solution gained heat. This is what we were monitoring. The reason why the solution gained heat is because the reaction lost heat. Energy is lost when two elements or compounds mix. The energy lost/ gain was heat. Heat is a form of energy as stated above in the previous paragraph. The sign of enthalpy for three out of the four reactions matches what was observed in the lab. For the last reaction, part four, the reaction gained heat not the solution like parts one through three. The negative enthalpy value for part four indicates that the reaction gained

This would influence the results by making the reaction perform better. Without contaminates the two compounds can react with just each other instead of what has contaminated the water. The second assumption is that the water is just a vessel for the chemical reaction between magnesium hydroxide and citric acid. Assuming that magnesium hydroxide and citric acid don’t individually react with water this would make the water a vessel. Due to part one and part three of the lab this assumption is incorrect. One possible source of experimental error could be not having a solid measurement of magnesium hydroxide nor citric acid. This is because we were told to measure out between 5.6g-5.8g for magnesium hydroxide and 14g-21g for citric acid. If accuracy measures how closely a measured value is to the accepted value and or true value, then accuracy may not have been an aspect that was achieved in this lab. Therefore, not having a solid precise measurement and accurate measurement was another source of experimental error.