The winners of this month’s puzzles will be published next month. For a chance to win a £25 book voucher, please send your completed puzzles to chemistryworld@rsc.org by 15 October.

Alternatively, you can send your answers to the address below:

Chemistry World
Royal Society of Chemistry
Thomas Graham House 
Science Park
Milton Road
Cambridge
CB4 0WF
UK

Please find the download link below.