Le Chatelier's Mini-Lab
Amy Kaznica, Sabrina Antle, Kristen Martin, Tim Furrer
Activity 1 (Mg(OH)- ↔ Mg+2 + 2OH-)
We reduced the pressure by pulling the syringe out and reducing the amount of space in the container. This caused the equilibrium to shift left towards reactants because there are more moles of gas present. We know this because we saw the pH change from 4.4 to 4.2; the color changed from dark green to light green.
Activity 2 (OH- + H+ ↔ H2O)
We increased the concentration of the H+ ion by adding HCl which made the equilibrium shift to the right. We know this because we saw the pH change from 10 to 4; the color changed from purple to pink. Then we added OH- ions and increased OH- ions shift back to reactants which was a product making the equilibrium shift towards the left (reactants). We know this because we saw the pH change from 4 to 9; the color changed from pink to green to blue.