Heat of Neutralization Formal Lab 1 PDF

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Heat of Neutralization Carlee Cassina September 15, 2020 Cara Savino CHE 121 80A

Purpose: The purpose of this experiment is to determine the heat of reaction for a neutralization reaction. For which acid, HCl, NaCl, or CH3COOH, is the greatest quantity of heat released per mole of H2O. Introduction In this experiment, various acids were combined to record results of heat neutralization and how many H2O moles were created as a product. A Calorimeter was used in this experiment which is a device for measuring the amount of heat involved in a chemical reaction or other processes. Equations that were used in this experiment: temp decrease x 50.0 g x 4.184 J/K-g, temp increase x 50.0 g x 4.184 J/K-g, heat gained by the calorimeter/ temperature increase, temp increase x 100g x 4.184 J/K-g, temp increase x heat capacity of the calorimeter, n=M x V, total joules released/ number of moles water produced. The first experiment was to heat 50 mL of distilled water and pour the heated water into the room temperature water to see how much enthalpy is occurring. The second and third was to see if 50 mL 1.0 M of NaOH mixed with 50 mL 1.0 M of HCl or CH3COOH(all room temp) and how much heat would be kept in the calorimeter when the chemical reaction would occur.

Procedure: A. Heat Capacity of Calorimeter Nest two styrofoam cups together. Slip a thermometer into a spit one-hole rubber stopper to where it won’t hit the bottom of the cup. Put the cardboard cover with a hole in the middle on top of the cup. Put the cup into a 400 mL beaker for stability. Place 50.00 mL of distilled water into the cup then place the thermometer in the cardboard hole. Wait for

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5 minutes then check the temperature of the room temp water. Next, take 50.00 mL of distilled water and place it in a clean and dry 250 mL beaker and heat the water with a low flame till 15 degrees above room temp and record the temperature. Now, pour as much of the heated water into the calorimeter as possible. Replace the lid and every 15 seconds for 3 minutes record the temperature of the water. B. Heat of Neutralization of HCl-NaOH Dry everything wet with a towel. Measure 50.00 mL of 1.0 M NaOH and add it to the calorimeter. Put the cardboard on without the thermometer. Measure 50.00 mL of 1.0 M HCl into a dry beaker. Let stand near each other for 3 minutes. Measure the temperature of the acid and rinse the thermometer with distilled water and wipe dry. Then do the same with NaOH. The temp shouldn’t be more or less than 0.5℃ . Adjust temp if needed then record temp. Carefully add HCl to NaOH and then stir gently and record temp for 3 minutes every 15 seconds. C. Heat of Neutralization of CH3COOH-NaOH Repeat the same process as in part B. Instead of HCl use 50.00 mL 1.0 M of CH3COOH and calculate heat. Results: A. Heat Capacity of Calorimeter 1. Temp of calorimeter and water before mixing: 24℃. 2. Temp of warm water: 91℃. 3. Max temp determined from your curve: 53℃. 4. Heat lost by warm water: 7949.6J

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B. Heat of Neutralization of HCl-NaOH 1. Temp of calorimeter and NaOH: 24℃. 2. Temp of HCl: 24℃. 3. ΔT determined for your curve after adding HCl to the NaOH: 29℃. 4. Heat gained by solution: 2092 J 5. Heat gained by calorimeter: 145 J 6. Total Joules released by reaction: 2,237 J 7. Complete: HCl+ NaOH= H2O + NaCl 8. The number of moles of HCl in 50 mL of 1.0 m HCl: .05 mol 9. The number of moles of H2O produced in reaction of 50 mL 1.0 M HCl and 50 mL 1.0 M NaOH: .05 mol 10. Joules released per mole of water formed: 121.336 kJ/mol C. Heat of Neutralization of CH3COOH-NaOH 1. Temp of calorimeter and NaOH: 23℃. 2. ΔT determined from cooling curve after adding CH3COOH to NaOH: 29℃ 3. Heat gained by solution: 9673.2 J 4. Heat gained by calorimeter: 2510.4 J 5. Total joules released by reaction: 12133.6 J 6. Complete: CH3COOH + NaOH: CH3COONA + H2O 7. The number of moles of H2O produced in reaction of 50 mL 1.0 M CH3COOH and 50 mL 1.0 M NaOH: .05 mol 8. Joules released per mole of water formed: 60.668 kJ/mol

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A. Heat capacity of Calorimeter

B. Heat of Neutralization of NaOH-HCl

C. Heat of Neutralization of NaOH-CH3COOH

Time- Temp(℃)

Time- Temp(℃)

Time- Temp(℃)

0-24

0-24

0-23

15-38

15-29

15-29

30-53

30-29

30-29

45-53

45-29

45-29

60-53

60-29

60-29

75-53

75-29

75-29

90-53

90-29

90-29

105-53

105-29

105-29

120-53

120-29

120-29

135-53

135-29

135-29

150-53

150-29

150-29

165-53

165-29

165-29

180-53

180-29

180-29

Sample Calculations: n= CxV The number of moles in HCl: 0.999 M x 0.05 L = 0.0499 moles = 0.05 moles The number of moles in NaOH: 0.907 M x 0.05 L = 0.0454 moles = 0.05 moles Discussion For the three parts of the lab especially part A there is a difference in heat as heated water is being added to room temp water having a more drastic change in temperature when combined compared to parts B and C as they only changed around 5-7 degree Celcius by chemical reaction where the water changed around 20-30 degrees as its the same properties just one is heated so

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nothing is chemically changing. The errors that could happen are pouring errors as too little or too much can be used for the chemical used, for part A the water could be boiled as stated not to as it could lose water, the beakers could have been cross-contaminated if not cleaned properly especially the thermometers, the HCl or the Ch3COOH could have been spilled and not added fully to the NaOH. Conclusion: This experiment shows how heat in each experiment can be determined as endothermic or exothermic based on using a calorimeter and how much energy can be needed or created to produce these reactions. Major errors can happen like when boiling the water for part A as the thermometer needs to really be watched. Another is not cleaning anything and adding other substances to it causing a reaction inside the beakers or calorimeter causing inaccurate temperature results. Somethings that could stop these are using 4 beakers (water, HCl, NaOH, and CH3COOH) to make sure a clean and dry beaker is being used. For the styrofoam cups swap those out for clean ones in case they’re not properly cleaned as the liquids are clear and not seen well in the cup.

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