Safety
Home chemistry is safe when you respect a handful of habits. None of this is about fear — it is about working so that a mistake stays small. Read this once before your first experiment, and skim the per-page safety notes every time.
This page is general good practice, not a substitute for the specific hazard information on each chemical and experiment page. When they give a more cautious instruction, follow it.
Personal protective equipment (PPE)
- Eyes first. Splash-rated safety glasses or goggles for every experiment, no exceptions. Eyes do not heal from a base splash the way skin does.
- Gloves appropriate to the chemical — nitrile for most solutions; avoid latex. Gloves are not armour: if something gets inside a glove, remove it immediately.
- Skin and clothes. Long sleeves, closed shoes, and an apron or old clothing. Tie back long hair, especially near any flame.
- Lungs. Work near an open window or under a range hood. Anything that smells sharp (ammonia, acids, chlorine, sulfur) needs real airflow, not just “a cracked window in the next room.”
Working habits
- Keep food and drink out of the work area, and never use kitchen glassware you will later eat from for non-food chemicals.
- Add acid to water, never water to acid, and add concentrated solutions slowly with stirring — dilution can release surprising heat.
- Never mix chemicals that aren’t in the procedure. Bleach with acids or ammonia releases toxic gas; concentrated oxidizers with fuels can ignite.
- Label everything you store. An unlabeled jar is eventually a mystery hazard.
Storage and incompatibles
Store chemicals cool, dry, and out of reach of children and pets, in their own labelled containers. Keep these families physically separated so a leak or spill can’t bring them together:
- Acids (hydrochloric, sulfuric, acetic) away from bases (sodium hydroxide, ammonia) — together they react violently and generate heat.
- Oxidizers (hydrogen peroxide, potassium permanganate, nitrates) away from fuels, acids, and anything organic (sugar, alcohol, oils).
- Water-reactive or hygroscopic solids (calcium chloride, sodium hydroxide) in tightly sealed containers.
- Store liquids below solids, and corrosives low down, so a fall is short.
Spill response
- On skin or in eyes: flush with copious running water for 15 minutes. This is the universal first response. Do not try to “neutralize” a chemical on skin — the neutralization reaction releases heat and makes the injury worse. Water, and lots of it, is the answer.
- On the bench: contain small liquid spills with paper towels working from the outside in. For acid or base spills, dilute heavily with water first (a little baking soda can neutralize an acid spill on a surface — not on skin).
- Remove contaminated clothing while flushing. Seek medical care for anything affecting the eyes, or for burns larger than a coin.
Waste disposal by category
Most dilute, benign solutions (table salt, baking soda, citric acid, vinegar) can go down the drain with plenty of water. But some things never do:
- Heavy-metal solutions and precipitates — silver (Ag), copper (Cu), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), lead (Pb) — are never poured down the drain. Let solids settle or filter them out, dry or bag the solids, and put them in the trash sealed, or better, hold them for a household hazardous-waste collection. These metals poison waterways and treatment plants.
- Strong acids and bases: neutralize to near-neutral pH (carefully, with stirring and eye protection) and dilute heavily before drain disposal, or hold for hazmat collection if large.
- Organic solvents and oils: never down the drain — collect and take to hazardous-waste drop-off.
- When in doubt, keep it in a labelled container and ask your local hazardous-waste program.
Adult supervision
An adult should be present and engaged for any experiment involving open flame, heating, electricity in contact with liquids, corrosive acids or bases, toxic salts (cobalt, silver, lead), or the potential to produce a gas. Younger children can do the low-hazard, kitchen-chemistry experiments with an adult running the setup. Match the person to the hazard rating on each page.
Emergency contacts
- Poison Control (US): 1-800-222-1222 — free, confidential, 24/7. Program it into your phone before you start.
- For fire, difficulty breathing, or a serious burn, call your local emergency number (911 in the US) first.
- Fill in your regional poison-control and emergency numbers here if you are outside the US.