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Edexcel International GCSE Chemistry
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Links for Chapter 23: Calculations from equations

Video clips and animations

Why do chemistry calculations? 1: Getting the proportions wrong.

This very short video shows a rocket made from a plastic bottle filled with a mixture of methane and oxygen in a 1:1 ratio by volume. You can see that it doesn't travel very far. From Mike Thompson's ChemPics on YouTube.

Why do chemistry calculations? 2: Getting the proportions right.

This repeats the last experiment, but this time getting the proportions right. Look at page 157 of the book to find the equation for the reaction. Notice that for every molecule of methane, you need two molecules of oxygen. According to Avogadro's Hypothesis (page 189), that means that to get the right reacting proportions, you need twice the volume of oxygen as of methane. That's what you have in this video. From Mike Thompson's ChemPics on YouTube.

I haven't been able to find anything else worthwhile. In truth, video and other web-based materials tend to be distracting when you are trying to learn to do chemistry calculations. The way to learn to do them is to sit down quietly with a book, a pencil, paper and calculator. If you do come across anything that you have found helpful, could you let me know via the address on the about this site page of Chemguide. It must, however, exactly match the approach to these calculations used in the chapter.

Instructions for practical work

I have referred to practicalchemistry.org as a reliable source of instructions for experiments. If you find anything really good from other sources, could you let me know via the address on the about this site page of Chemguide.

Chemical quantities menu

A limited number of experiments at the time of writing (June 2009), none of which I would personally use. Keep an eye on it, though.

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