Author: Elizabeth Bramhall
Balancing equations is one of the most fundamental skills in chemistry and when mentioned in class is, more often than not, met with the phrase “I can’t balance equations”. I developed this method to help those students who couldn’t get their heads around lowest common multiples and multi step mental processes. All my students can confidently apply this method to a range of examples, and the method works up to A-level standard questions too.
The one key point to emphasise is that compounds or molecules cannot be changed by the addition of “little numbers”. Rather than talk about water being a molecule so can’t change I tend to refer to as a “clump” of atoms and draw a small diagram showing these atoms stuck together. They can only add whole new “clumps” not part of them. (This terminology is extremely unchemical and so I would not suggest using with students who may take the subject further than GCSE, but it gives the impression of a group of atoms which are stuck together).
The idea of using new rows every time a new molecule is needed allows the nifty trick of being able to count up the rows to come up with stoichiometry (or balancing numbers). This tends to get a bit of a “wow” from the students who have been introduced to other methods previously.
The video works alongside the worksheet to talk you through the first worked example. You can then look through the harder worked example and have a go at the scaffolded question as a class and then allow students to choose which examples they want to try from the differentiated examples.
With huge thanks to Arsh and Mohammed (Y10) from Bolton School for their hours of help in producing the video.
Download the files below:
RSC Ed Tech Group 