Question

(Le Chatelier's Lab)

• Do your observations support your prediction based on Le Chatelier’s Principle? Explain clearly using your color observations as evidence.
• Explain the direction equilibrium shifted for each activity in this lab. Justify why the equilibrium shifted in that direction.
• Based on the color change you observe, is the equilibrium for the solution in the ice water shifting left or right?
• Based on the color change you observe, is the equilibrium for the solution in the hot water shifting left or right?
• Do your observations indicate that the reaction is exothermic or endothermic? That is, based on your observations, is heat a product or a reactant? How do you know?
• What is the net ionic equation of this reaction with heat included in the equation?
  
• Are equilibrium shifts reversible? Justify using evidence from the lab.

Answer 1

• If you change the \(\color{blue}{\text{concentration}}\) of a reactant then the position of the equilibrium will shift to counteract that change.

• If you change the \(\color{red}{\text{temperature}}\) of the reaction the equilibrium will shift to counteract that change.

• for blue when concentration was decreased equilibrium shift to left

• for red when concentration was decreased equilibrium shift to right

• for blue when concentration was increased equilibrium shift to right

• for red when concentration was increased equilibrium shift to left

• If the temperature is increased the equilibrium will shift to favour the reaction which will reduce the temperature. The endothermic reaction is favoured.
  
• If the temperature is decreased the equilibrium will shift to favour the reaction which will increase the temperature. The exothermic reaction is favoured.

Heat is Released for an exothermic reaction

CO(H₂O)$_6^{2+}$ + 4Cl$^-$ $\leftrightarrow$ COCl$_4^{2-}$ + 6H₂O

COCl$_4^{2-}$ (blue)

CO(H₂O)$_6^{2+}$ (red)

The reverse reaction is also favoured if the concentration of the \(\color{red}{\text{product}}\) is increased, so that product is used.