29 topics
Chemistry help, from moles to mechanisms
Nearly every quantitative chemistry problem is the same problem: get to moles, use the balanced equation, come back out. Students who see that pattern find the numerical half of the course collapses into one method with different units on either end; students who do not end up memorising a separate procedure per chapter.
Where students get stuck
Limiting reactant problems
The mistake is comparing masses, or comparing moles directly. Convert each reactant to moles, then divide each by its coefficient in the balanced equation. The smallest result is the limiting reactant — that division step is what accounts for a reaction needing three of one thing per one of another, and skipping it gives the wrong answer whenever the coefficients differ.
Le Châtelier — which way does it shift?
Treat the stress as something the system removes. Add a reactant, it shifts to consume it. Increase pressure, it shifts toward whichever side has fewer moles of gas. Temperature is the one that catches people: heat is a reactant in an endothermic reaction and a product in an exothermic one, so write it into the equation explicitly and it behaves like everything else. Adding a catalyst shifts nothing.
ICE tables and the x approximation
Set up initial, change, equilibrium as usual, and the change row is always the coefficients times x with signs from the direction of the shift. The approximation everyone forgets to justify: you can drop x from the denominator when K is small relative to the initial concentration — the usual rule is when the initial concentration divided by K exceeds about 500. If it does not, you solve the quadratic, and courses do test that case deliberately.
Organic mechanisms feel like memorisation
They are the opposite. Every mechanism is electrons moving from somewhere rich to somewhere poor, and every arrow starts at a lone pair or a bond and ends where there is room. Once you can identify the nucleophile and the electrophile, most arrows have exactly one sensible destination. Memorising fifty mechanisms is what happens when that step is skipped.
What's covered
Chemistry topics you can work through with a tutor, generate practice on, or turn into flashcards and a study plan.
Foundations
- Significant figures, units, and dimensional analysis
- Atomic structure and isotopes
- Electron configuration and orbitals
- Periodic trends
- Ionic, covalent, and metallic bonding
- Lewis structures, VSEPR, and molecular polarity
Reactions and stoichiometry
- Balancing equations
- The mole and molar mass
- Mass–mole–particle conversions
- Limiting reactant and percent yield
- Empirical and molecular formulas
- Solution concentration and dilution
- Precipitation, acid–base, and redox reaction types
Physical chemistry
- The gas laws and the ideal gas equation
- Thermochemistry, enthalpy, and Hess's law
- Entropy, Gibbs free energy, and spontaneity
- Reaction rates, rate laws, and activation energy
- Equilibrium, K expressions, and ICE tables
Acids, bases, and electrochemistry
- Strong and weak acids and bases
- pH, pOH, Ka and Kb
- Buffers and the Henderson–Hasselbalch equation
- Titration curves and equivalence points
- Oxidation numbers and balancing redox half-reactions
- Galvanic and electrolytic cells, cell potential
Organic chemistry
- Functional groups and IUPAC nomenclature
- Isomers and stereochemistry
- Substitution and elimination mechanisms
- Addition reactions of alkenes
- Reactions of alcohols, carbonyls, and carboxylic acids
Chemistry questions
Can I show it a structure or a mechanism I've drawn?
Yes — hold your page up to the camera or share your screen. Drawing organic structures in a chat box is painful enough that most students never get help with them, which is exactly the problem this removes.
Does it check my units and significant figures?
Yes, and it will flag them, because in chemistry those are marks. Dimensional analysis is also a genuinely useful check on your own setup — if the units do not cancel to what you want, the setup is wrong before the arithmetic starts.
Is organic chemistry covered, or just general chem?
Both. Nomenclature, stereochemistry, and the standard substitution, elimination and addition mechanisms are all in scope, with structures drawn out on the whiteboard as the electrons move.
Stuck on chemistry right now?
Talk it through out loud, share your screen, and watch it worked out step by step on a whiteboard.
Start free — no card