Introduction
In a chemical reaction, either the products or reactants tend to have a higher enthalpy than the other. In some cases, the enthalpy of reactants is greater than the enthalpy of products. On the other hand, in other cases, the enthalpy of products tends to be greater than the enthalpy of reactants. A reaction involving the products with higher enthalpy than the reactants is said to be endothermic (Brown, et al, 172). On the other hand, chemical reactions where the enthalpy of reactants is higher than the enthalpy of products are said to be exothermic (Brown, et al, 172). The reaction between zinc and hydrochloric acid involves a change in enthalpy. The knowledge in the enthalpy change involved in the reaction is important in understanding the application of the reaction.
Enthalpy change in the reaction between zinc and hydrochloric acid can be determined experimentally by recording the change in the temperature of the system during the reaction. Temperature change indicates the change in heat energy of the system. When a system gains heat energy from the surrounding, the temperature of the surrounding decreases. On the other hand, the temperature of the surrounding increases when a system of a reaction loses heat energy. It is on this basis that enthalpy change of a system involved in a chemical reaction can be determined. In this case, the reaction is carried out in a calorimeter to minimize heat loss.
This experiment was intended for comparing the H of the reaction involving zinc and hydrochloric acid obtained when Styrofoam and market brand calorimeters are used. The experiment also sought to determine the specific heat capacity of Styrofoam.
Methods
Activity 1: Determining the specific heat capacity of Styrofoam cup
The following materials were used during this activity: Styrofoam cups, cardboard, glassware (250 mL beakers and Erlenmeyer flask, tongs), water, gloves, digital thermometer, scissors, market brand calorimeter, and hot plate.
During the activity, all the materials were first gathered at once. 60mL of water was then put in a beaker and heated to a temperature of C. The equation; mc∆t=Q was used to determine the quantity of heat (Q) gained by the water as a result of the heating. The water was then poured into the calorimeter and its temperature recorded immediately it became stable. The quantity of heat gained by the calorimeter was then determined using the equation shown below:
Qw=msCs∆t+heat gained by thesystem
Activity 2:
Results
Discussion
Conclusion
Research Connection
References
Brown, William H, Brent L. Iverson, Eric V. Anslyn, and Christopher S. Foote. Organic Chemistry. , 2014. Print.
