Class 11 Chemistry

1.1 What matter is made of Mixtures and pure substances, elements and compounds, and the physical methods that separate a mixture. 1.2 Measuring, and significant figures Measured values carry units and a stated number of significant figures. Precision and accuracy differ. 1.3 The laws of chemical combination Five patterns in the masses and volumes of reacting substances, explained by Dalton’s atomic theory. 1.4 The mole The mole is 6.022 × 10²³ particles, chosen so that the formula mass in grams is one mole. 1.5 From mass to formula Percentage composition gives mole ratios, the empirical formula, and with the molar mass, the molecular formula. 1.6 Stoichiometry A balanced equation gives mole ratios, which give the amounts formed and the limiting reagent.