Chem Lab #5 Report

Chem Lab #5 Report - Lab#5 Report Thermochemistry Sarah...

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Lab #5 Report: Thermochemistry Sarah Aistrup Sirus Saeedipour Michael Aldrighetti Hasan Naser Sec. 425 Cassie Ward

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INTRODUCTION: The purpose of this lab was to: 1. Determine the change in temperature that occurs when NaOH and HCl are combined in a calorimeter. 2. Preform variants of the first procedure for the specified reactions and calculate the heat of the reaction for each. Both of the experiments being investigated involve determining the amount of heat produced or consumed by a process which is measured through a device called a calorimeter being used for this investigation. The results of each test will be collected using the LoggerPro program. The process being observed today is a chemical reaction involving a form of energy: heat. When a change in the energy of a system results in a temperature difference, then that energy has been transferred as heat. A system is a specific part of the universe that is of interest, in our experiment an example would be the chemical reaction between NaOH and HCl. Now, recalling the Law of Conservation of Energy, stating, the total quantity of energy in the universe is assumed constant. From this definition we can conclude that energy can never be destroyed or created. To achieve this quality, all forms of energy can be converted from one form to another. In order for this to hold true, heat that is either lost or gained from the system must come from somewhere (Chang 230). Where you might ask? The surroundings, or the rest of the universe! The equation to express the heat released or absorbed from the system is: q = msDT For this equation, q corresponds to heat, m is the mass of the sample, s is specific heat, and finally DT represents the change in temperature. The specific heat refers to the amount of heat gained or lost when one gram of a substance changes temperature by one Celsius degree. The units for heat
are expressed in Joules (J), an equation to express Joules is: J = g * [J / (g * °C)] * °C Processes that absorb energy into the system are known as endothermic, for these DT holds positive values. During exothermic processes energy is given off by the system, so DT would have negative values. Thermochemistry seeks to study and understand heat changes that take place in chemical reactions. Now, taking a look back at the reactions being observed through this lab, water is the primary

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This note was uploaded on 04/14/2010 for the course CHEM 13891 taught by Professor Hierl during the Spring '10 term at Kansas.

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Chem Lab #5 Report - Lab#5 Report Thermochemistry Sarah...

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