Lab 8 Le Chatlier’s Principle

Results Sheet, Experiment 9

Part 1 Mg(OH)2(s)  Mg2+(aq) + 2 OH-(aq)

Observations:
Well Initial Observation
(Step 5) Step 6, 7, 9 or 10
(depending on the well) Step 12
C1 Turned pink 1 drop, removed most pink. 2 drops, pink gone
C2 Turned pink 4 drops started lightening. 10 drops pink nearly gone
C3 Turned pink Became thinner Became thicker
C4 Turned pink Became thicker Became thinner

Part 1. Questions:
When asked about a shift to an equilibrium, the reaction either shifts toward reactants or toward products (the reaction starts at equilibrium, something is done to the reaction; after the disturbance, the reaction proceeds in the reverse direction as written forming more reactants to relieve the stress or the reaction proceeds in the forward direction to form more product).

In Part I the reaction you observed was Mg(OH)2 (s) ↔ Mg2+ (aq) + 2 OH- (aq). Compare the colors you observed in the experiment and answer these questions:

Which way should the equilibrium shift when HCl is added? How do your results support your answer?

It should shift toward the reactants. It is shown by removing the pink color from the product.

B. Which way should the equilibrium shift when Na2 EDTA is added? How do your results support your answer?

It should shift toward the reactants. It is shown by removing the pink color from the product.

Is this reaction endothermic or exothermic? How do you know?
Endothermic. The reaction shifts to the left and it consumes heat.

Part 2. HSO4-(aq) + H2O(l)  H3O+(aq) + SO42-(aq)

Observations:
Well Step 3, 5, or 12
(depending on the well) Step 14
A1 Turns more of an orange color than pink
A2 (Control) None None
A3 Color turns darker
A4
Initial Temperature: 43 degrees C. No noticeable change
A5
Initial Temperature: 14 degrees C No noticeable change

Questions:
In Part II the