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Enthalpy Change of a Chemical Reaction

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CHE101 - Laboratory Report;Name: Francescia Housworth;Date: 9- -14;Title;Enthalpy Change of a Chemical Reaction;Purpose;This section consists of 1 or 2 sentences that describe the goals and benefits of the experiment.;Students should use complete sentences. You can find this by reading the Background;information in LateNite labs. Do not copy and paste any portion of the description.;Procedure;Experiment 1;Materials we will need;Erlenmeyer flask;100 mL of water;Calorimeter;Temperature bath;2 thermometers;First we take an Erlenmeyer flask and the temperature bath from the shelf. Set the bath;temperature to 600C. Now take the thermometer and attach it to the flask. Fill the flask with 50;mL of water and place it in the temperature bath. While the water is heating, remove the;calorimeter from the shelf. Fill the calorimeter with 50 mL of water and attach the other;thermometer to it. Record the temperature in your notes. When the temperature of the flask;reaches 600C, remove the flask. Record the temperature of the liquids combined in the;calorimeter. Then we need to clean up our work area.;Experiment 2;Materials we will need;Calorimeter;Thermometer;0.15g of magnesium;0.35g of magnesium;Balance;50 mL of 1.0 M hydrochloric acid;0.25g of magnesium;First we will need to take a calorimeter and a balance from the shelf. Next place the calorimeter;on the balance to weigh it. Record the mass of the empty calorimeter in your notes. Then;remove the calorimeter from the balance. Next we need to attach the thermometer to the;calorimeter. Record the temperature in your notes. Now we are going to add 50 mL of 1.0 M;hydrochloric acid to the calorimeter. Now also add 0.15 g of magnesium to the calorimeter.;Watch the thermometer and record the maximum temperature displayed on the thermometer.;Now measure and record the mass of the calorimeter and its contents on the balance. This was;trial 1.;Then for trial 2, we will repeat the steps with a new calorimeter. In this trial we will use 50 mL;of hydrochloric acid and 0.25 g of magnesium. Remember to record the maximum temperature;displayed by the thermometer in the calorimeter.;Then for trial 3, we will repeat the steps with a new calorimeter. We will use 50 mL of;hydrochloric acid and 0.35 g of magnesium. Then record the maximum temperature displayed;on the calorimeter. Now we need to clean up our work area.;Data;Chemistry;TheEnthalpyChangeofaChemicalReaction;Experiment1;1. Record the following;a;Initial temperature in the calorimeter (C);21.50C;b;Maximum temperature in the calorimeter from the reaction (C);35.30C;c;Calculate deltaT by subtracting (b) from (c);deltaT = Tinitial (C);13.8;2. What was the initial heat energy before mixing the cold and hot water? To calculate this you;need to use the formula;Qinitial = m1*Cp*T(of the hot water) + m2*Cp*T(of the cold water);where Q is the heat energy, m is the mass, Cp is the specific heat of water 4.184 J/g*C, and T is;the temperature.;3.3.Whatwasthefinalheatenergyaftermixingthecoldandhotwater?Tocalculatethisyouneedto;usetheformula;Qfinal = (m1+m2) * Cp * Tfinal;4. What is the heat energy of the calorimeter? You can calculate the calorimeter heat energy as;the difference between the initial and final heat energies.Choose the closest answer.;5.5.Whatisthecalorimeterconstant?Youcancalculatethecalorimeterconstant,Ccal,perdegree;changeofthecalorimeterbytakingthecalorimeterheatenergyanddividingitbythetemperature;changeundergonebythecalorimeter;Experiment2;1. Record the following for each of the three trials;Trial1;a;Mass of the empty calorimeter (g);18.6g;b;Initial temperature in the calorimeter;(C);21.50C;c;Maximum temperature in the;calorimeter from the reaction (C);35.20C;d;e;Calculate deltaT by subtracting (b);from (c);deltaT = Tmaximum - Tinitial (C);Mass of the calorimeter and its;35.20C21.50C=13.70C;68.738g;contents after the reaction (g);f;Calculate the mass of the contents of;the calorimeter (g): e - a;68.73g18.6g=50.138g;g;Calculate the moles of Mg reacted;(MW=24.305 g/mole);0.15g*1mole/24.305g=0.000617molesofMg;Trial2;a;Mass of the empty calorimeter (g);18.6g;b;Initial temperature in the calorimeter (C);21.50C;c;Maximum temperature in the calorimeter;from the reaction (C);44.30C;d;Calculate deltaT by subtracting (b) from (c);deltaT = Tmaximum - Tinitial (C);44.30C21.50C=22.80C;e;Mass of the calorimeter and its contents;after the reaction (g);68.829g;f;Calculate the mass of the contents of the;calorimeter (g): e - a;68.829g18.6g=50.229g;g;Calculate the moles of Mg reacted;(MW=24.305 g/mole);0.25gMg*1mole/24.305g=0.01029molesof;Mg;Trial3;a;Mass of the empty calorimeter (g);b;18.6g;Initial temperature in the calorimeter (C);21.50C;c;Maximum temperature in the calorimeter;from the reaction (C);53.40C;d;Calculate deltaT by subtracting (b) from;(c);deltaT = Tmaximum - Tinitial (C);53.40C21.50C=31.90C;e;Mass of the calorimeter and its contents;after the reaction (g);68.921g;f;Calculate the mass of the contents of the;calorimeter (g): e - a;68.921g18.6g=50.321g;g;Calculate the moles of Mg reacted;(MW=24.305 g/mole);0.35gMg*1mole/24.305g=0.0144molesofMg;2. Calculate the heat released into the solution for the 3 reactions, according to;q(reaction)= Ccal * Delta T + mass(contents) * Cp (contents) * deltaT;Cp is the specific heat (assume 4.18 J/goC);a;Trial 1(J);b;Trial 2 (J);c;Trial 3 (J);3. Find the molar heat of reaction for each experiment in units of KiloJoules / (mole of Mg) by;dividing the heat of reaction (converted to KJ by dividing by 1000) by the moles of Mg used.;a;Trial 1KJ/mol;b;Trial 2 KJ/mol;c;Trial 3 KJ/mol;4. Calculate and record the average molar heat of reaction from the three results.;It is important to include all the data from the experiment in your lab report. Data and;calculations are best organized and presented in tables. Copy and paste the Short answer;portion of the lab here. This has all of the tables, questions, and areas for calculations.;Conclusions;Your conclusion should include the following;What did you learn from this experiment? Base your conclusions on experimental;observations.;A proper conclusion connects the experiment (data, observations, and calculations);results back to key principle(s) stated in the background section. This should be a paragraph.

 

Paper#15997 | Written in 18-Jul-2015

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