Overview
Remember to show your calculations!
The change in temperature need to be in Kelvin. Please make sure to convert the data. Some of you did not measure the amount of NaCO3 used in their trial. Used the amount weight in those cases. The results will be slightly off. If you have different starting temperatures for your solutions on part 2, take the average temperature.
- Make a table showing the number of trials you did for each part.
- Calculate the enthalpy in kJ/mol for each trial performed.
- Calculate the average enthalpy for each reaction (If you have more than 1 trial)
- Use the three enthalpies to calculate the enthalpy of the reaction (4) in bold (page 53)
- I will send you the picture of my notebook and page 53.
- From part2 #2 and on where you see . Something it is a summary version of the first number of that table.
- page 53
the reaction heats of the three stages are given as x, y, and z joules, respectively. Thus:A →> D AH = w joules or A--> BB→> CC-> DAH = x joulesAH = y joules53Then, according to Hess's law, the heat of the reaction in going from A to D is the samewhether change is achieved directly or through a series of separate stages.Hess's law is important because it enables us to add and subtract heat changes algebraically and to calculate the enthalpy of a reaction which may be impossible to determine directly by experiment.PROCEDURERead the instructions below carefully before starting this exercise so that you know precisely what you have to do. You will determine the enthalpy change (4 H) for each process below.- NaCO3(s) + 2HClaq) → 2NaCkaa) + H20 (lia) + C02(g)
- NaOH(aq) + HCl (aq) → NaClaq) + H20 (lia)
- NazCO3(s) → NazCO3(aq)
- Use the same calorimeter for the entire experiment
- You are provided with 2.0 M hydrochloric acid, solid sodium carbonate (NazCO3), and
- Using a graduated cylinder, place 30.0ml of the hydrochloric acid into the calorimeter provided. After it has stood for several minutes, measure the temperature of the acid as precisely as you can.
- Place between 2.50 and 3.00g of sodium carbonate into a plastic weighing cup. Pour the solid into the calorimeter as quickly and completely as possible. Begin stirring immediately.