Titration Curves - Introduction

This was a whirlwind introduction to Titration Curves. Tomorrow, we will look at the calculations to determine the initial and final pH. Next term, we will look at how to calculate equivalence point volume and pH, and in the buffer region.

pH of Weak Acids

This is a very difficult concept. Every student should be able to write a hydrolysis equation, base dissociation expression (K_B), and calculate K_B from pK_A or K_A (provided in the question). Beyond that, it will take a lot of practice:

Weak Acids

It is a bit trickier to calculate the pH of a weak acid. This is because they only partially dissociate. However, this means that these acids have an equilibrium constant (called the acid dissociation constant), which can be used to calculate the hydronium ion concentration:

The process for doing this is:

1. Write the balanced equation for the dissociation with water.
2. Write the acid dissociation expression.
3. Substitute and solve
• [hydronium] = [conjugate base] = x
• [acid] = original concentration stated in the question (only partially dissociated)
4. Calculate pH

Acids and Bases

This was a recap of last year. The videos are from the topic being taught to a Level 2 class.

Solubility Overview

Solubility and Solubility Product

The dissolving of a sparingly soluble solute can be represented by an equilibrium equation:

As this is an equilibrium, we can write an equilibrium expression, called the Solubility Product:

The smaller the Solubility Product, the less soluble a solute is.

Solubility is usually expressed in one of two units: grams per litre (g L^-1); or moles per litre (mol L^-1).

We can use the solubility of a solute to calculate the Solubility Product, and use the the Solubility Product to calculate the solubility of a solute. Once we master these two skills, we have a good understanding of solubility.

Ionic Product and The Common Ion Effect

Ionic Product is the same as Solubility Product, but when two solutions (of known concentration) are combined and the ions may form a precipitate. If Ionic Product is larger than Solubility Product, a precipitate does form. If they are equal, it is a saturated solution. If Solubility Product is larger, no precipitate will form.