Determination of enthalpy change of neutralization and combustion of a liquid G11 Nana, Lynn, Anne, Joesy, Eric January 24, 2024 Purpose: To determination of enthalpy change of neutralization and combustion of a liquid. Safety precautions: 1. lab coat 2. safety goggles Apparatus: Tripod, pipette, beaker, alcoholburner, thermometer, polystyrene cup, lid. Chemicals: 1. HCl- hydrochloric acid 2. NaOH- sodium hydroxide 3. Water Steps: 1. Add water to a flask, weight the water. 2. Clamp the flask to a stand at a suitable height, and put a spirit burner. 3. Weigh the spirit burner. 4. Record the initial temperature of the water by thermometer. 5. Extinguish the flame. 6. Record the final temperature of the water. 7. Re-weigh the spirit burner. 8. Calculate the enthalpy change of combustion. 1. Wear safety glasses and a lab coat. 2. Using a pipette fitted with a safety filler, place 25.0cm³ of 1.00 mol dm acid into an expanded polystyrene cup. 3. Measure the temperature of acid. 4. Using a pipette fitted with a safety filler, place 25.0 cm³ of the alkali into a beaker. 5. Measure the temperature of the alkali. 6. Add the alkali to the acid, stir with the thermometer and measure the maximum temperature reached. Calculation: volume of water heated 66.8cm^3 mass of ethanol burned 2.1g temperature change +303k 4.18 x 2.1 x66.8 = 0.5864KJ 2.1/46 =0.0457mol 0.5864/0.0457= 12.83KJ/mol volume of 1mol/dm^3HCl 25.0cm^3 volume of 1mol/dm^3NaOH 25.0cm^3 initial temperature of acid 11 initial temperature of alkali 15 maximum temperature reached 14 4.18 x (14-0.5(11+15)) x (25+25) = 0.209KJ -0.209/0.025= -83.6KJ/mol Errors: We made several mistakes in the experiment. First, we did not handle the alcohol lamp lightly at the beginning. Second, due to the lack of experimental equipment, the data is not accurate enough. For example, there is no copper beaker that can better conduct heat and a container that can reduce heat loss. Failure to measure the initial temperature value in time during the experiment may lead to inaccurate experiment. Then when the experiment was over there was no alcohol lamp covered twice. In the second experiment, when we used pipeet, we did not read the line of sight at the concave level, resulting in inaccurate readings. We don’t have draught shield. And for both experiment is not under standard condition. Improvements: 1. Becareful about alcohol burner. 2. Measure the temperature of water before the experiment. 3. Use a well conduct heat container and use a lid for reduce heat loss. 4. Use thermometer and pippet should be same with eye level.