Chemical Reactions and Quantities
Unlock the foundational rules of chemistry by translating formulas, balancing chemical equations, and using the mole to predict reaction quantities with confidence.
Like Duolingo, but for Chemical Reactions and Quantities. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
A short one: 11 levels across 2 sections, about 22 minutes end to end, roughly 4 days at five minutes a day. It moves through Reading and Balancing Reactions and Quantities and Reaction Math. It starts from scratch.
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Key ideas in Chemical Reactions and Quantities
- Subscripts show the fixed ratio of atoms bonded inside every single unit
- Changing the amount of liquid changes the total number of molecules, not the ratio inside each molecule
- A missing subscript implicitly means a count of one atom
- Ionic compounds must have a net electrical charge of zero
- Multiple copies of an ion are added until positive and negative charges cancel out
- Equal and opposite charges cancel in a 1-to-1 ratio without extra subscripts
- Covalent compounds share electrons rather than balancing static charges
- Names of covalent molecules use numerical prefixes like mono-, di-, and tri- to tell you the exact count of each atom
- 'Di-' means two atoms of that element are present
- Polyatomic ions are clusters of atoms that travel and react together as one charged package
- Parentheses protect the identity of the cluster before applying an outside multiplier subscript
- Placing a subscript directly next to an existing number multiplies only that single element
- In chemical reactions, atoms only rearrange and are never created or destroyed
- Every single atom in the starting reactants must be accounted for in the final products
- Subscripts define the specific chemical identity of a compound (H2O is water, H2O2 is hydrogen peroxide)
- Coefficients in front change the quantity of molecules without altering what the substance is
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Chemical Reactions and Quantities the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
In a formula like H₂O, what does the little lowered number 2 tell you?
Get it right to open this lesson and 10 more in the app.
Where Chemical Reactions and Quantities takes you
- 1
Reading and Balancing Reactions
- Decoding Formulas and Compounds
- Balancing Equations Systematically
- 2
Quantities and Reaction Math
- The Mole: Counting by Weighing
- Stoichiometry and Limiting Reactants
2 sections · 4 units · 11 levels. Built to play, not to enroll.
You pick the voice
Chemical Reactions and Quantities is taught in the The Bestie style: your friend who just gets it. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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