Acid Strength

Acids can be described as concentrated or dilute. This is about how much water is used to make them up. They can also be described as strong or weak. This is about the concentration of hydronium ions. Concentration has some effect, but the extent to which an acid dissociates (turns into ions) is more important:

Chemical Minds

Check out this wikispace, set up by Michele McMahon at St Cuthbert's College.

Calculating pH of Bases

Calculating pH - Strong Acids

Strong acids fully dissociate - all of their hydrogen atoms react with water to become hydronium ions. We use the concentration of hydronium ions to calculate the pH:

pH = -log[H₃O⁺]

Likewise, we can use the pH to calculate the hydronium ion concentration:

[H₃O⁺] = 10^-pH

Acids and Bases - Moving Beyond Year 11

Equilibrium Constant

Mr Nicoll was unwell so left these instructions:

1. Work through the notes and exercises about Equilibrium Constant in Beginning Chemistry.
2. Do Question Two, in the 2013 NCEA paper (AS91166).

Here is a short video talking about Equilibrium Constant and going through the answers to the exam question:

Concentration and Equilibrium

Dynamic Equilibia and le Chatelier's Principle

Today was an introduction to these ideas including a demonstration of the nitrogen dioxide/dinitrogen tetroxide equilibrium.

Explaining Rates of Reaction

We looked at the main conditions that can increase reaction rates. It led to a discussion about depressants and psychedelics, but here is the actual Chemistry content from today: