Refer to the net ionic equation below to answer the following questions:
Co(H2O)6^+2 + 4Cl- <==> CoCl^-2 + 6H2O
1. In what direction was the equilibrium shifted by:
a. Addition of HCl
b. Addition of water
c. Addition of AgNO3
d. Increasing the temperature
e. Decreasing the temperature
2. How do you explain the results described in answers 1a and 1b?
3. Explain the results observed when AgNO3 was added. (Hint: The concentration of something was being lowed.)
4. Is the reaction shown above exothermic or endothermic? How do you know?
Net Ionic Equation is:
Co(H2O)6^2+ +4Cl- <--> CoCl4^2- + 6H2O
1. In what direction was the equilibrium shifted by:
a. Addition of HCl
b. Addition of water
c. Addition of AgNO3
d. Increasing the temperature
e. Decreasing the temperature
Le Chatelier's Principle tells us that when a system at equilibrium is disturbed that it will shift to undo what we've done to it. Therefore,
a. Adding HCl it will shift to the right BECAUSE the reaction wants to use the extra HCl.
b. Now you do this one based on a.
c. Notice that AgNO3(aq) + Cl^-(aq) ==> AgCl(s) + NO3^-(aq). This REMOVES Cl^- from the rxn; therefore, it will shift (left/right) to undo what we've done.
d and e. I don't know the answers to these since you don't have the information about the rxn being endothermic or exothermic.
The answers to the other questions are included in the explanations above.
Thanks! I got the other answers.
1. In what direction was the equilibrium shifted by:
a. Addition of HCl: The equilibrium will shift to the left. This is because HCl is a source of chloride ions (Cl-), and according to Le Chatelier's principle, when more chloride ions are added, the system will try to reduce their concentration by consuming them to form more CoCl2-, shifting the equilibrium to the left.
b. Addition of water: The equilibrium will not be affected. Water (H2O) is present on both sides of the equation, and its concentration does not change. Therefore, the equilibrium position remains unchanged.
c. Addition of AgNO3: The equilibrium will shift to the left. AgNO3 is a source of silver ions (Ag+), which reacts with chloride ions to form a precipitate of silver chloride (AgCl). This decreases the concentration of chloride ions (Cl-) on the right side of the equation, causing the equilibrium to shift to the left to produce more chloride ions and reestablish the balance.
d. Increasing the temperature: The equilibrium will shift to the left. This reaction is exothermic, meaning it releases heat. According to Le Chatelier's principle, increasing the temperature will favor the endothermic direction, which is the reverse reaction. The equilibrium will shift to the left to consume heat, reducing the temperature, and reestablish the balance.
e. Decreasing the temperature: The equilibrium will shift to the right. This reaction is exothermic, meaning it releases heat. According to Le Chatelier's principle, decreasing the temperature will favor the exothermic direction, which is the forward reaction. The equilibrium will shift to the right to produce more heat, increasing the temperature, and reestablish the balance.
2. The results described in answers 1a and 1b can be explained as follows:
a. Addition of HCl: The addition of HCl increases the concentration of chloride ions (Cl-), which shifts the equilibrium to the left. This results in a decrease in the concentration of the Co(H2O)6^+2 complex ion and an increase in the concentration of the CoCl^-2 ion.
b. Addition of water: The addition of water does not affect the equilibrium position since water is present on both sides of the equation and its concentration remains constant.
3. When AgNO3 is added, it reacts with chloride ions (Cl-) to form a precipitate of silver chloride (AgCl). The silver chloride precipitate lowers the concentration of chloride ions (Cl-) on the right side of the equation. To restore equilibrium, the system shifts to the left to produce more chloride ions by dissociating the CoCl^-2 complex ion. This explains the observed result when AgNO3 is added.
4. The reaction shown above is exothermic. We can determine this by examining the stoichiometry of the equation. The forward reaction involves the formation of Co(H2O)6^+2 and Cl- ions, while the reverse reaction involves the formation of CoCl^-2 and H2O molecules. Since the forward reaction consumes heat, it is the exothermic reaction.
To answer these questions, we need to understand what net ionic equation represents and how each factor affects the equilibrium position of the given reaction.
1. In what direction was the equilibrium shifted by:
a. Addition of HCl:
When HCl is added to the reaction, it increases the concentration of Cl- ions. According to Le Chatelier's principle, adding a species that appears on the left side of the equation will shift the equilibrium to the right. Therefore, the equilibrium would shift to produce more CoCl^-2 and H2O.
b. Addition of water:
Adding water to the reaction affects the concentration of water molecules, but since water appears on both sides of the equation, it does not change the equilibrium position. Thus, adding water does not shift the equilibrium in any direction.
c. Addition of AgNO3:
AgNO3 dissociates into Ag+ and NO3- ions. Since Ag+ ions can react with Cl- ions to form a precipitate (AgCl), adding AgNO3 increases the concentration of Ag+ ions. According to Le Chatelier's principle, adding a species that reacts with another species will shift the equilibrium away from that species. Therefore, the equilibrium would shift to the left to consume more Co(H2O)6^+2 and Cl- ions.
d. Increasing the temperature:
Increasing the temperature of an exothermic reaction favors the backward reaction, whereas for an endothermic reaction it favors the forward reaction. Since we don't know whether the given reaction is exothermic or endothermic, we cannot determine the direction of the shift.
e. Decreasing the temperature:
Decreasing the temperature of an exothermic reaction favors the forward reaction, whereas for an endothermic reaction it favors the backward reaction. Without knowing whether the given reaction is exothermic or endothermic, we cannot determine the direction of the shift.
2. How do you explain the results described in answers 1a and 1b?
In answer 1a, the addition of HCl increases the concentration of Cl- ions, which causes the equilibrium to shift to the right and produce more CoCl^-2 and H2O. This is because the added HCl reacts with Co(H2O)6^+2 and the excess Cl- ions push the equilibrium towards the right side.
In answer 1b, adding water does not affect the equilibrium position since water appears on both sides of the equation. Therefore, the addition of water does not cause any shift in the equilibrium.
3. Explain the results observed when AgNO3 was added:
The addition of AgNO3 increases the concentration of Ag+ ions. Ag+ ions can react with Cl- ions to form a precipitate of AgCl. As a result, the equilibrium shifts to the left to consume more Co(H2O)6^+2 and Cl- ions, reducing the concentration of Cl- ions and forming more AgCl precipitate. Therefore, the observed result is a decrease in the concentration of Cl- ions due to the formation of AgCl precipitate.
4. Is the reaction shown above exothermic or endothermic? How do you know?
Based solely on the given net ionic equation, we cannot determine if the reaction is exothermic or endothermic. The equation does not provide information about the energy change associated with the reaction. Additional information, such as enthalpy change (ΔH), is needed to determine whether the reaction is exothermic (negative ΔH) or endothermic (positive ΔH).