Spontaneity Of A Chemical Reaction Lab
INTRODUCTION
Thermodynamics is a branch of physical science in which deals with the relations between heat and other forms of energy. The ability to predict if a chemical reaction will occur spontaneously or non-spontaneously is an important aspect of thermodynamics. Spontaneity is determined from free energy, or Gibbs free energy. The equation (1) gives the relationship of how entropy (∆S) and enthalpy (∆H) along with temperature affects the amount of free energy, and henceforth the spontaneity. A spontaneous process may be quick or slow, and it is only affected by temperature and energy, therefore it is not related to kinetics or reaction rate. equation (1):
If entropy is less than enthalpy, the enthalpy term determines if the reaction …show more content…
And since AgNO3 is a one to one mole ratio the number of moles of Ag ions can be calculated. Then once more the moles of Ag ions equal moles of Cl- because once again there is a one to one mole relationship. From all of that the concentration of Cl- can be found by moles divided by liters which declined with every titration because less and less solution was needed. After the molarity of the Cl- is found the molarity of Pb2+ is half the molarity of Cl- since there is 2 Cl- ions for each Pb2+ ion. Then Ksp can be calculated from equation (3). Then a graph can be created to find free energy of the reaction by lnKsp vs. …show more content…
Enthalpy and entropy was determined from the equation of the best fit line located on the graph (1).
Graph (1)
equation (4): equation (5): The free energy was found to be around 1.931•10^4 or roughly 19.31kJ. This was determined by using both equations (4) and (5) of. The first equation gave the answer of 1.93375•10^4 J and the second produced 1.9296•10^4J. Since both calculated responses were very close, the average between the two was taken and found to be 1.931•10^4 or roughly 19.31kJ. Consequently, this makes the reaction nonspontaneous.
There are many sources of error that could have happened thought the progression of the experiment. For example, the uptake of solid PbCl2 into the pipet. A few pieces of solid PPT could be hard to detect especially if they were relatively small. Doing so could cause for the calculated Ksp to be larger because of all the extra AgNO3 that will then be needed to titrate the solution to the proper endpoint. Another error could be over titrating. Since it was the first time working with chemicals in this type of titration it’s hard to determine in the outcome was correct. If visible red precipitate is seen in the flask then over titration has occurred, thus too much AgNO3 was added. This again will cause for the Ksp value to be calculated at a larger magnitude than what it is. Lastly, another source of error could have come
Thermodynamics is a branch of physical science in which deals with the relations between heat and other forms of energy. The ability to predict if a chemical reaction will occur spontaneously or non-spontaneously is an important aspect of thermodynamics. Spontaneity is determined from free energy, or Gibbs free energy. The equation (1) gives the relationship of how entropy (∆S) and enthalpy (∆H) along with temperature affects the amount of free energy, and henceforth the spontaneity. A spontaneous process may be quick or slow, and it is only affected by temperature and energy, therefore it is not related to kinetics or reaction rate. equation (1):
If entropy is less than enthalpy, the enthalpy term determines if the reaction …show more content…
And since AgNO3 is a one to one mole ratio the number of moles of Ag ions can be calculated. Then once more the moles of Ag ions equal moles of Cl- because once again there is a one to one mole relationship. From all of that the concentration of Cl- can be found by moles divided by liters which declined with every titration because less and less solution was needed. After the molarity of the Cl- is found the molarity of Pb2+ is half the molarity of Cl- since there is 2 Cl- ions for each Pb2+ ion. Then Ksp can be calculated from equation (3). Then a graph can be created to find free energy of the reaction by lnKsp vs. …show more content…
Enthalpy and entropy was determined from the equation of the best fit line located on the graph (1).
Graph (1)
equation (4): equation (5): The free energy was found to be around 1.931•10^4 or roughly 19.31kJ. This was determined by using both equations (4) and (5) of. The first equation gave the answer of 1.93375•10^4 J and the second produced 1.9296•10^4J. Since both calculated responses were very close, the average between the two was taken and found to be 1.931•10^4 or roughly 19.31kJ. Consequently, this makes the reaction nonspontaneous.
There are many sources of error that could have happened thought the progression of the experiment. For example, the uptake of solid PbCl2 into the pipet. A few pieces of solid PPT could be hard to detect especially if they were relatively small. Doing so could cause for the calculated Ksp to be larger because of all the extra AgNO3 that will then be needed to titrate the solution to the proper endpoint. Another error could be over titrating. Since it was the first time working with chemicals in this type of titration it’s hard to determine in the outcome was correct. If visible red precipitate is seen in the flask then over titration has occurred, thus too much AgNO3 was added. This again will cause for the Ksp value to be calculated at a larger magnitude than what it is. Lastly, another source of error could have come