| CATALYST | What is a substance that speeds a chemical reaction while remaining unchanged? (8) |
| ANTIGEN | What is a substance that triggers the production of antibodies? (7) |
| ALKALI | What is a substance that turns litmus paper blue? (6) |
| ALKALINE | What is a substance, able to turn litmus paper blue, with a a pH greater than seven? (8) |
| 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) |
| 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) |
| RETARDANT | A substance that prevents or inhibits a chemical reaction (9) |
| KERATIN | Karen, it is a substance found in nails (7) |
| SCEPTIC | Way to accommodate church's priest in charge, while remaining unconvinced (7) |
| OVERACTS | Exaggeratedly melodramatic while remaining with production of Cats (8) |
| IDEMPOTENT | Of an element or quantity in mathematics, remaining unchanged when multiplied by itself (10) |
| ASITIS | Remaining unchanged like its following (2,2,2) |
| PULSE | Runner, for example, that speeds up after exertion (5) |
| TIMELAPSE | ___ photography (filmmaking technique that speeds up slow activity): Hyph. |
| ACCELERATOR | The car pedal that speeds up the engine (11) |
| ATOM | What is the smallest part of an element that can take part in a chemical reaction? (4) |
| INITIATOR | In chemistry, a substance that starts a chain reaction (9) |
| INHIBITOR | A substance that interferes with a chemical or biological process (9) |
