| CATALYST | What is a substance that speeds a chemical reaction while remaining unchanged? (8) |
| ALKALINE | What is a substance, able to turn litmus paper blue, with a a pH greater than seven? (8) |
| ALGICIDE | Mixture of acid and gel containing iodine is a substance that destroys seaweed (8) |
| RESIDUUM | What is a substance left after chemical activity? (8) |
| ADHESIVE | What is a substance used for sticking things together? (8) |
| REACTANT | In chemistry, a substance that participates in and is altered by a chemical reaction (8) |
| OVERACTS | Exaggeratedly melodramatic while remaining with production of Cats (8) |
| AMETHYST | Maintaining speed, a van in York street is purple (8) |
| EMPHASIS | Energy and speed unchanged? Result: stress (8) |
| ANTIGEN | What is a substance that triggers the production of antibodies? (7) |
| ALKALI | What is a substance that turns litmus paper blue? (6) |
| SPACEAGE | Clever chap gathering speed - it started with rockets (5,3) |
| CATALYZE | Clay seat used to influence a chemical reaction (8) |
| FUELCELL | Producer of electricity from a chemical reaction |
| FUMES | Coming from the Latin meaning "touchwood", what is a substance, apart from food, that can transmit i |
| PLACEBO | What is a substance with no therapeutic effect, used as a control in testing new drugs? (7) |
| TESTTUBE | Piece of laboratory glassware used for in vitro studies or experiments with Bunsen burners such as a chemical reactions (4,4) |
| ENZYME | A biological catalyst, usually a protein, that speeds up specific chemical reactions in living organisms (6) |
| RIPENER | Chemical that speeds up a fruit's aging process |
| IDEMPOTENT | Of an element or quantity in mathematics, remaining unchanged when multiplied by itself (10) |
