Enthalpy of Various Reactions - Lab 3

# Enthalpy of Various Reactions - Lab 3 - Introduction...

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Introduction: Enthalpies of various types of reactions will be calculated by performing a number of different experiments. To calculate the enthalpy, the following equation is used: E = mcΔT; where ‘E’ stands for heat energy gained or lost by the system, ‘m’ represents the mass of the substance, ‘c’ represents the specific heat capacity of the substance, and ‘ΔT’ represents the change in temperature of the substance. If the heat energy we were to calculate happens to be negative in sign, it would be exothermic (heat released by reaction); however, if it were positive it would be an endothermic reaction (heat absorbed by reaction). In these experiments we are assuming that the heat absorbed by the Styrofoam calorimeter and the heat lost to the surroundings is negligible. *ADD IN OTHER REFERENCE FOR THEORY SECTION* Procedure: As described in General Chemistry CHM 1301/1311 2009 Lab Manual . Observations: Part 1: Specific Heat Capacity of a Metal (Zinc) Table .0: Various Measurements Data Trial 1 Trial 2 Mass of Empty Calorimeter (g) 5.1029 5.4501 Volume of Water in Calorimeter (mL) 20.0 20.0 Mass of Calorimeter with Water (g) 24.7478 24.6148 Temperature of Boiling Water (°C) 100.0 100.0 Mass of Zinc Metal (g) 11.88 11.78 Time (s) Temperature(°C) Trial 1 Temperature (°C) Trial 2 0 22.3 22.4 30 22.3 22.4 60 22.3 22.4 90 22.4 22.5 120 22.4 22.5 150 22.4 22.5 180 22.4 22.5

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Time (s) Temperature (°C) Trial 1 Temperature (°C) Trial 2 10 26.5 26.3 20 26.5 26.4 30 26.7 26.5 40 26.6 26.5 50 26.6 26.5 60 26.5 26.4 70 26.6 26.5 80 26.5 26.5 90 26.6 26.4 100 26.5 26.4 110 26.5 26.3 120 26.5 26.3 140 26.5 26.2 160 26.5 25.6 180 26.4 26.3 200 26.4 26.0 220 26.4 25.6 240 26.4 25.4
Qualitative Observations: Once heated metal was added to water in calorimeter, the heat of the water increased particularly fast and in a drastic fashion. Part 2: Enthalpy of Neutralization Data Trial 1 Trial 2 Trial 3 Trial 4 Volume of 1.1M HCl (mL) 50 50 ----------- - ----------- - Volume of 1.1M HNO 3 (mL) ----------- - ----------- - 50 50 Concentration of NaOH (M) 1.0 1.0 1.0 1.0 Volume of NaOH (mL) 49.5 49.5 49.5 50 Mass of Calirometer + Lids + Solution (g) 106.4301 106.4426 107.0275 107.5777 Temperature Time (min.) Trial 1 Trial 2 Trial 3 Trial 4 0 22.0 21.8 22.2 21.6 1 21.9 21.9 22.2 21.7 2 22.0 21.8 22.2 21.7 Time (s) Temperature (°C) Trial 1 Temperature (°C) Trial 2 Temperature (°C) Trial 3 Temperature (°C) Trial 4 10 29.0 28.8 28.6 28.8 20 29.2 28.9

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## This note was uploaded on 01/17/2010 for the course CHM BIO1130 taught by Professor Houseman during the Fall '09 term at University of Ottawa.

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Enthalpy of Various Reactions - Lab 3 - Introduction...

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