After this, 50.0 mL of 2.0 M HCl and 50.0 mL of 2.0 M NaOH are gathered. The temperatures of both solutions are first measured and recorded. Every time the thermometer is placed into a different solution, the thermometer is rinsed and dried. Then, 50.0 mL of 2.0 M HClare measured and put into the calorimeter, and then 50.0 mL of 2.0 M NaOH is also measured out. Then, it is added into the calorimeter, and the cover is quickly placed. After the thermometeris inserted, the temperature is recorded to the nearest 0.1 every 20 seconds for 3 minutes.℃Then, the same process is repeated again two more times. The second time, 2.0 M NH4Cl and 2.0 M NaOH are used, and for the third reaction 2.0 M NH3and 2.0 M HCl.
Results and Analysis:Data Table 1. Find the Heat Capacity of the Calorimeter SubstanceTemperature ()℃Room Temperature H2O23.5Hot H2O59.0Data Table 2. Temperature of Combination of the Hot Water and Room Temperature WaterTime (seconds)Temperature ()℃20 40.54040.16039.68039.510039.512039.514039.516039.5 18039.5Using this data, the heat capacity of the Styrofoam cup calorimeter can be calculated. First, a graph of the data in Data Table 2. can be created to estimate the instantaneous temperature of the solutions as soon as the hot water was added to the room temperature water. The line does not cross the points past the time of about 60 seconds because the linear relationship of continuous decreasing temperature does not continue that far.
Tmixwas estimated to be about 40.9 ℃.Then, the average temperature of the hot and cool water of Tavgwas calculated, and this is because the difference between the average temperature and the instantaneous temperature isΔTfor calculating heat absorbed by the calorimeter and lost from the water.Calculation of Tavg of the hot and cold water combined togetherCalculation of the heat lost from the waterCalculation of the heat absorbed by the calorimeterThe heat absorbed of something is just the negative of the heat evolved from some other thing giving the heat to that something.
Calculation of the heat capacity of the calorimeterThe heat capacity of the calorimeter is the heat that the calorimeter absorbs each time the temperature of the solution changes by 1 degree Celsius.Data Table 3. Initial Temperatures of the HCl and NaOHSubstanceTemperature ()℃50.0 mL of 2.0 M HCl23.550.0 mL of 2.0 M NaOH24.0Since the initial temperature of the HCl and NaOH are not agreeing ±0.2, the values are ℃averaged.Calculation of Average Temperature between Initial Temperatures of HCl and NaOHData Table 4. Temperature of the reaction between HCl and NaOHTime (seconds)Temperature ()℃20 26.04026.0
6025.58025.510025.512025.514025.516025.518025.5Data Table 5. Initial Temperatures of the NH4Cl and NaOHSubstanceTemperature ()℃50.0 mL of 2.0 M NH4Cl23.550.0 mL of 2.0 M NaOH27.5Since the initial temperature of the NH4Cl and NaOH are not agreeing ±0.2, the values are ℃averaged.Calculation of Average Temperature between Initial Temperatures of NH4Cl and NaOH
Data Table 6. Temperature of the reaction between NH4Cl and NaOHTime (seconds)Temperature ()℃20 23.54024.06024.08024.010024.012024.014024.016024.018024.0Data Table 7. Initial Temperatures of NH3and HClSubstanceTemperature ()℃
50.0 mL of 2.0 M NH322.050.0 mL of 2.0 M HCl23.0
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