FAQs and help

I would like people to enjoy chemistry as much as I do and don’t see why you should pay me.

GCSEs are the main qualification taken by students aged 15 to 16 in England, Wales and Northern Ireland. Science and Chemistry GCSEs are designed as two-year courses, assessed by written examinations at the end of the course. Scottish National courses have similar content. 

GCSEs are graded from 9 to 1 (grade 9 is the highest) in England, and from A* to G in Wales and Northern Ireland.

As part of the National Curriculum, the Department for Education publishes Science programmes of study showing the content that must be covered. The examination boards base their specifications on this content, with some differences in approach and with varying additional content.

A Levels are examinations taken by students at around the age of 18. A Level Chemistry courses normally take two years to complete, with all the examinations taken at the end in the summer. They are usually required for university entry.

A Level teaching content is divided in two, which I have identified as Core and Further on the web site. It is possible to take an AS Level examination based on the Core content. Some students may choose to do this at the end of their first year of studies, then either drop the subject or continue on to study the Further content.

AS Levels are graded from A to E (grade A is the highest), and A Levels from A* to E (grade A* is the highest).

The Department for Education publishes the required skills, knowledge and understanding required by all Chemistry AS and A Level courses. The examination boards base their specifications on this content, with some differences in approach and with varying additional content.

Check you that have a PDF reader such as Adobe Reader installed. Some of the worksheets are quite large and you might have not allowed enough time for the file to completely download.

Try right-clicking as an alternative method for your downloads (which gives you a progress bar to see how much has downloaded). You will then have to load the pdf file from Acrobat separately.

Do you have a pdf reader installed? If you do, check that the installation is not corrupted. Check to see if the problem occurs with other pdf files. For example, try to open Help files and manuals for software on your computer as these may be pdf files. Try installing or re-installing Adobe Reader or another pdf reader.

No plugin is needed to view these, but you must allow sufficient time for the required files to download. The second and subsequent loading of the molecules should be faster if you have allowed your browser to cache the files.

There may, of course, be no resource on the site containing your keyword. However, do check your spelling carefully – you’re unlikely to get a response to a misspelled word like “chemestery”.

Avoid looking for a phrase with common words like atheto, and so on. Don’t be wildly ambitious. For example, is there a diagram of a fractionating column with the names of each fraction? will yield a lot of unexpected results.

Maybe, but not yet. There is still a lot to do.

A4 paper measures 21.0 cm × 29.7 cm (roughly 8¼ in × 11¾ in). This is slightly larger than US letter size (8¼ in × 11 in). The diagram explains the A range of International Paper sizes. Wherever A4 paper is mentioned on the site, US letter paper can be used instead if A4 is not available to you.


I am British, so you will see words like analyse, centre, colour, dived, licence and travelled (rather than analyze, center, color, dove, license and traveled). I use ‑ise endings rather than ‑ize endings (both are okay in British English but I prefer to apologise rather than to apologize).

Chemical names are spelt using IUPAC recommendations. This means you will see aluminium instead of aluminum (sorry USA), but sulfur instead of sulphur (sorry UK).

I use SI units for quantities, sometimes called metric units. For example, you will see metres, kilograms and cubic decimetres (but not feet, pounds and gallons).