Free Chemistry Help

Why general chemistry grades actually slip

Chemistry grades usually break at stoichiometry, and they break for a reason that has nothing to do with chemistry: it is the first topic where you must hold a multi-step conversion in your head without the problem telling you the steps. Students who were fine through atomic structure hit mole conversions and conclude they are bad at chemistry. They are bad at dimensional analysis, which is a much smaller and more fixable thing.

The second break is thermodynamics and equilibrium, where the symbols multiply and sign conventions start to matter. A negative sign in an enthalpy problem is worth the same as the whole calculation, and sign errors are the single most common lost mark on those papers.

There is also a pure volume problem. Chemistry exams are long and most students do not finish. Speed on routine conversions is therefore worth marks directly, which makes drilling the boring part a legitimate exam strategy rather than a waste.

Free resources worth your time

Everything below is free to use without payment. The note on each one says when to reach for it, because the usual problem is not a shortage of material — it is picking the wrong kind of material for the stage you are at.

• Khan Academy — Chemistry Free course Good coverage and good practice. Start at the stoichiometry unit if you are already mid-term.
• The Organic Chemistry Tutor Video channel Despite the name, the general chemistry problem-walkthroughs are the strongest free resource for exam-style questions.
• OpenStax — Chemistry 2e Free textbook Free full textbook. Use the end-of-chapter exercises; that is where the value is.
• MIT OpenCourseWare — 5.111 Principles of Chemical Science Free course Complete course with exams and solutions. Harder than most intro courses, which makes it a good honesty check.

What to do with the time you actually have

If you have the rest of the term

Drill unit conversions until they are automatic — grams to moles to particles, in both directions, without thinking. This is the load-bearing skill for the entire course and it is pure practice.

If you have a week

Work past papers under exam time limits. Chemistry is a time-pressure exam and students who have only ever done untimed homework discover this too late.

If you have tonight

Rehearse the standard problem shapes: limiting reagent, percent yield, dilution, gas laws, pH. Write the first two lines of each from memory until the setup is reflexive.

Work out what you actually need first

Before you spend a weekend on this, get the number. If the final is worth 20% and you are sitting at 88%, an A needs 98% and a B needs 48% — those two facts call for completely different weeks. Run your real numbers through the final grade calculator, then come back and pick the plan that matches the gap. The finals-week triage guide covers how to split time across several courses at once.