Lab # 4: Le Chatelier's Principle
Lab 4: Le Chatelier’s Principle
Name: Cammey Mahowald
Lab Partners: None
Date of Experiment: March 16, 2015
Course: CHE 112
Abstract:
The purpose of this experiment is to understand the components of a reaction at chemical equilibrium and use Le Chatelier’s principle to predict the direction an equilibrium position will shift upon changes in the concentration, temperature, and pressure. It was determined that in the equilibrium of chromate and dichromate it is an exothermic reaction and in the equilibrium of ferrocyanide and ferric ferrocyanide that it is an equilibrium shift to the left after adding NaOH.
Experiment and Observation:
The purpose of this experiment was to observe the color change and the concentration to determine the …show more content…
Sources of error came from the drop sizes varying from the pipet and the droppers. When collecting the solutions in the empty pipet, we may have not collected all of the solution, however I do not believe this would make a huge different. Another source of error is not leaving the solution in the warm water bath and cold-water bath long enough to observe the change in reaction and or color. The thing I seemed to struggle with is noticing a huge color difference. It was apparent that chromate was yellow and dichromate was orange, although I did not see a darkening of the orange to indicate a change.
Questions for Exercise A:
A. Use your results to determine if the forward reaction in the potassium chromate/HCl reaction endothermic or exothermic. Explain your answer, using Table 1 to help construct your thoughts.
According to table, I would assume the reaction is exothermic. I would assume this because when the chromate/HCl were in warmer temperatures it was solid orange, then when adding the chromate/HCl in the ice bath it formed a precipitate. The precipitate forming shows that there is an addition of crystals, meaning a shift to the …show more content…
C. If the concentration of the reactant H2 was increased from 1.0 x 10-2 M to 2.5 x 10-1M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.
(1.0x10-4 mol/L)2 NH3 / (1.0x10-2) N2 (2.5x10-1 ) 3 H2=
.000000008= Q < K=.06
The reaction will shift to the right.
D. If the concentration of the reactant H2 was decreased from 1.0 x 10-2 M to 2.7 x 10-4M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.
(1.0x10-4 mol/L)2 NH3 /(4.0) N2 (2.7x10-4)3 H2 =
Q= 2.05x10-13 < K=.06
The reaction will shift to the right.
E. If the concentration of the product NH3 was decreased from 1.0 x 10-4 M to 5.6 x 10-3M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.
(5.6x10-3 mol/L)2 NH3/(4.0) N2 (1.0x10-2)3 H2 =
Q= 7.84x10-12 < K=.06
The reaction will shift to the right .
Questions for Exercise B:
A. From your observations and data collected in Data Table 3, describe the direction of the equilibrium position shift upon addition of
Name: Cammey Mahowald
Lab Partners: None
Date of Experiment: March 16, 2015
Course: CHE 112
Abstract:
The purpose of this experiment is to understand the components of a reaction at chemical equilibrium and use Le Chatelier’s principle to predict the direction an equilibrium position will shift upon changes in the concentration, temperature, and pressure. It was determined that in the equilibrium of chromate and dichromate it is an exothermic reaction and in the equilibrium of ferrocyanide and ferric ferrocyanide that it is an equilibrium shift to the left after adding NaOH.
Experiment and Observation:
The purpose of this experiment was to observe the color change and the concentration to determine the …show more content…
Sources of error came from the drop sizes varying from the pipet and the droppers. When collecting the solutions in the empty pipet, we may have not collected all of the solution, however I do not believe this would make a huge different. Another source of error is not leaving the solution in the warm water bath and cold-water bath long enough to observe the change in reaction and or color. The thing I seemed to struggle with is noticing a huge color difference. It was apparent that chromate was yellow and dichromate was orange, although I did not see a darkening of the orange to indicate a change.
Questions for Exercise A:
A. Use your results to determine if the forward reaction in the potassium chromate/HCl reaction endothermic or exothermic. Explain your answer, using Table 1 to help construct your thoughts.
According to table, I would assume the reaction is exothermic. I would assume this because when the chromate/HCl were in warmer temperatures it was solid orange, then when adding the chromate/HCl in the ice bath it formed a precipitate. The precipitate forming shows that there is an addition of crystals, meaning a shift to the …show more content…
C. If the concentration of the reactant H2 was increased from 1.0 x 10-2 M to 2.5 x 10-1M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.
(1.0x10-4 mol/L)2 NH3 / (1.0x10-2) N2 (2.5x10-1 ) 3 H2=
.000000008= Q < K=.06
The reaction will shift to the right.
D. If the concentration of the reactant H2 was decreased from 1.0 x 10-2 M to 2.7 x 10-4M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.
(1.0x10-4 mol/L)2 NH3 /(4.0) N2 (2.7x10-4)3 H2 =
Q= 2.05x10-13 < K=.06
The reaction will shift to the right.
E. If the concentration of the product NH3 was decreased from 1.0 x 10-4 M to 5.6 x 10-3M, calculate the reaction quotient (Q) and determine which way the equilibrium position would shift.
(5.6x10-3 mol/L)2 NH3/(4.0) N2 (1.0x10-2)3 H2 =
Q= 7.84x10-12 < K=.06
The reaction will shift to the right .
Questions for Exercise B:
A. From your observations and data collected in Data Table 3, describe the direction of the equilibrium position shift upon addition of