Short interactive lessons that ask a question before they explain. One session takes about ten minutes and ends with questions to check what you have understood.
Mixtures and pure substances, elements and compounds, and the physical methods that separate a mixture.
Class 11 · Chemistry Counting Atoms by Weighing FreeMeasured values carry units and a stated number of significant figures. Precision and accuracy differ.
Class 11 · Chemistry Counting Atoms by Weighing FreeFive patterns in the masses and volumes of reacting substances, explained by Dalton’s atomic theory.
Class 11 · Chemistry Counting Atoms by Weighing FreeThe mole is 6.022 × 10²³ particles, chosen so that the formula mass in grams is one mole.
Class 11 · Chemistry Counting Atoms by Weighing FreePercentage composition gives mole ratios, the empirical formula, and with the molar mass, the molecular formula.
Class 11 · Chemistry Counting Atoms by Weighing FreeA balanced equation gives mole ratios, which give the amounts formed and the limiting reagent.
Class 12 · Chemistry Solutions FreeMass percentage, mole fraction, molarity and molality. Only the volume-based measures change with temperature.
Class 12 · Chemistry Solutions FreeSolubility of solids depends mainly on temperature. For gases, solubility is proportional to pressure.
Class 12 · Chemistry Solutions FreeEach component’s partial vapour pressure is its pure vapour pressure times its mole fraction.
Class 12 · Chemistry Solutions FreeWeaker or stronger attraction between unlike molecules raises or lowers the vapour pressure. Azeotropes.
Class 12 · Chemistry Solutions FreeFour properties that depend only on the number of solute particles, each usable to find a molar mass.
Class 12 · Chemistry Solutions FreeDissociation and association change the number of particles. The van’t Hoff factor i corrects for it.
Noescio