Use the formula triangle: moles = mass ÷ molar mass. Write down what you know, identify what you need to find, and apply the correct equation. Always check units — mass in grams, molar mass in g/mol. Show every step of your work, including unit cancellation, to avoid careless errors.

Use a mnemonic to memorise the order, then learn the pattern: the higher the metal, the more reactive it is, the harder it is to extract, and the more vigorously it reacts with water and acid. Potassium is the most reactive, and platinum is the least reactive. Learn the extraction method for each group.

Count the atoms of each element on both sides, then add coefficients (big numbers in front of formulas) to make the numbers equal. Never change the subscripts within a formula. Start with the element that appears in the fewest compounds, and leave hydrogen and oxygen for last.

The most common mistakes are: not reading the question carefully, using the wrong units in calculations, confusing state symbols, writing incorrect chemical formulas, and not showing working in calculation questions. Most of these are avoidable with careful exam technique and targeted practice.

Learn the homologous series and their general formulas first, then practise naming and drawing structures for each family. Focus on alkanes, alkenes, alcohols, and carboxylic acids. Use flashcards for functional groups and reaction conditions. Practise past paper questions to see how organic chemistry is tested.

The most frequently tested practical skills include: heating substances, measuring temperature changes, collecting gases, titration, and filtration. Common experiments include electrolysis, rates of reaction, acid-base titrations, thermal decomposition, and displacement reactions. Know the apparatus names, safety precautions, and how to interpret your results.