Full Lab Report - Calorimetry - CH 104 Full Lab Report Calorimetry Introduction The purpose of the Calorimetry experiment was to determine the heat of

# Full Lab Report - Calorimetry - CH 104 Full Lab Report...

• Assignment
• 3
• 85% (13) 11 out of 13 people found this document helpful

This preview shows page 1 - 2 out of 3 pages.

CH 104 Full Lab Report - Calorimetry Introduction The purpose of the Calorimetry experiment was to determine the heat of different solutions in exothermic and endothermic reactions. Using Hess’s law, we were required to calculate the enthalpy of each reaction. Calorimetry is a measurement of the energy evolved or absorbed as heat in a chemical or physical process. 1 This definition of calorimetry can be used to determine the enthalpy change of many, but not all, chemical processes. In reactions where a calorimeter cannot be used to determine enthalpy change, Hess’s law is a useful second option. Hess’s Law states that if a reaction is a sum of two or more other reactions, H for the overall process is the sum of the H values of those reactions. 2 Enthalpy refers to the amount of heat released or absorbed in a reaction. Upon completion of this experiment we found the enthalpy values for each endothermic reaction using Hess’s Law. The percent error was calculated using the measured H rxn value and the value obtained through Hess’s Law. It was discovered that the H rxn value of reaction 3 was -23.16 ± 0.905 KJ/mol with a percent error of 11%. Experimental Determination of molar enthalpy is a two-step process. First, the overall exchange of heat (q rxn ) must be found. This can be found using eq. 1 below; where m is the mass of the solution, C is the specific heat capacity of the solution (4.18 J/g in our experiment), and ∆T is the change in temperature. q rxn =− m solution ×C solution ×∆T (1) Eq. 1 shows the heat absorbed or released which is equal to the mass of the solution multiplied by the specific heat capacity and the change in temperature.