Introduction to Organic Chemistry - Alkanes

I'm not a fan of teaching this topic the way Beginning Chemistry does. The following blog posts will be how I taught this in 2014. Hopefully this will complement the work being done in class with our student teacher.

I prefer to "get into it" with the functional groups and cover types of reactions, nomenclature and isomerism over and over again, in context. So, we jumped straight into using MolyMods to make as many isomers of C₅H₁₂ as possible.

Here are the questions we tried at the start of the next lesson:

Revision Lesson: Equilibrium

Revision Lesson: Energy Changes

Revision Lesson: Molecule Polarity

Revision Lesson: Solid Types

Today we did a brief overview of the one of the topics that will be in an Achievement Standard in our upcoming exam:

pH Overview

Today, I taught Mrs Naseem's class and we did an overview of pH and pH Calculations. Here are the whiteboard notes that I gave them. They may be useful to complement the work we did in class:

pH of Strong Bases

One of the more difficult skills is calculating the pH of a strong base. To do this, we need to know how to find the hydronium ion concentration from the hydroxide ion concentration:

Acids and Bases Videos

Here are some videos of the key concepts being taught in previous years:

2013

2014



2013


2013


2014

Acids, Bases, Conjugates and Amphiprotic Species

There is a very useful definition of acids and bases worth remembering:

Acids = "proton donors"
Bases = "proton acceptors"

Then, we looked at the pH of some salts and tried to justify the results. For example:

To clarify, ammonium chloride was acidic and sodium ethanoate was alkaline.

Acid-Base Introduction

This was a short overview of the acid-base aspect of the topic. There are a few new things added to what we were expected to know from last year:

1. How to calculate pH from the hydrogen (actually hydronium) ion concentration.
2. How to calculate the hydronium ion concentration from the pH
3. How to link pH, hydronium ion concentration and properties, such as rate of reaction

We also found out a couple of "lies" from last year:

1. pH goes below zero and above 14
2. hydrogen ions in solution are actually hydronium ions (H₃O⁺)
3. Salts are not always neutral - they may be acidic or alkaline (basic)

Equilibrium Homework Answers