How to Learn the Common Chemistry Formulas
Chemistry is full of compounds you meet every day — water, salt, carbon dioxide — and each has a formula worth knowing by heart. Recognising them speeds up equations and lab work. This deck pairs common substances with their chemical formulas.
There are 14 cards in the deck below. You can read through them, practise them right here with the flip-card player, and then save the deck to study properly with spaced repetition — the method that makes them stick for months, not minutes.
Why the common chemical formulas is hard to memorize (and the fix)
The subscripts trip people up (is water H2O or H2O2?), and a few formulas are non-obvious (table salt is NaCl, not "salt"). Learning the compound-to-formula pair fixes both.
The fix is active recall plus spaced repetition. Instead of re-reading the list (which feels productive but barely works), you test yourself — pull each answer out of memory — and you review each card on a schedule that stretches over time. Every time you successfully recall a fact, the memory gets stronger and the next review is pushed further out. That's how you go from "I saw it once" to "I just know it."
The fastest way to learn the common chemical formulas
- Break it into small batches. Learn the everyday ones first (water, CO₂, salt, oxygen), then the acids and bases, then the rest.
- Test, don't re-read. Look at the question, say the answer out loud before flipping the card. The little struggle to recall is what builds the memory — a smooth re-read does almost nothing.
- Review on a schedule. Spaced repetition shows you each card right before you'd forget it. Get one right and it comes back in a few days, then a week, then a month. Miss one and it comes back sooner.
- Keep sessions short and daily. Five to ten minutes a day beats a two-hour cram every time. Consistency is the whole game.
One fact per card. The small subscript number tells you how many atoms of the element just before it — H₂O means two H and one O.
The full deck: the Common Chemistry Formulas
Here's every card in the set. Practise them above, or save the deck and let spaced repetition schedule your reviews automatically.
| Compound | Formula |
|---|---|
| What is the chemical formula for water? | H₂O |
| What is the chemical formula for carbon dioxide? | CO₂ |
| What is the chemical formula for oxygen gas? | O₂ |
| What is the chemical formula for table salt? | NaCl (sodium chloride) |
| What is the chemical formula for glucose? | C₆H₁₂O₆ |
| What is the chemical formula for ammonia? | NH₃ |
| What is the chemical formula for methane? | CH₄ |
| What is the chemical formula for hydrochloric acid? | HCl |
| What is the chemical formula for sulfuric acid? | H₂SO₄ |
| What is the chemical formula for sodium hydroxide? | NaOH |
| What is the chemical formula for hydrogen peroxide? | H₂O₂ |
| What is the chemical formula for baking soda? | NaHCO₃ (sodium bicarbonate) |
| What is the chemical formula for nitrogen gas? | N₂ |
| What is the chemical formula for ozone? | O₃ |
Save this deck and actually remember it
Create a free account, keep this 14-card deck, and we'll schedule every review at the perfect moment. First deck free forever — no credit card.
Study this deck free →FAQ: learning the common chemical formulas
How long does it take to learn the common chemical formulas?
Most people can lock in the common chemical formulas within one to three weeks of short daily sessions. With spaced repetition doing 10–14 cards a day, you'll recognise them within days and recall them reliably within a couple of weeks.
What's the best way to memorize the common chemical formulas?
Active recall plus spaced repetition. Test yourself instead of re-reading, and review on a schedule that spaces the cards out over time. Flashcards are built for exactly this — which is why the deck above is the fastest path.
Is this deck free?
Yes. You can practise all 14 cards on this page for free with no account. Sign up (also free) to save the deck and let spaced repetition schedule your reviews so it sticks long-term.