Ch 1 covers the foundational concepts of chemistry — laws of chemical combination, dalton's atomic theory, mole concept, molarity, and stoichiometric calculations essential for all further chemistry.
Laws: conservation of mass (Lavoisier), definite proportions (Proust), multiple proportions (Dalton), Gay Lussac's law of gaseous volumes, Avogadro's law. Mole: 6.022 × 10²³ particles. Molar mass = mass of 1 mole in grams. Number of moles n = given mass/molar mass = given molecules/Avogadro number.
Molarity (M) = moles of solute/volume of solution in litres. Molality (m) = moles/kg of solvent. Mass percent = (mass of solute/mass of solution) × 100. Stoichiometry: mole ratios from balanced equations to calculate reactant/product quantities. Limiting reagent: consumed first, determines product amount.
Download: https://ncert.nic.in/textbook/pdf/kech101.pdf | Part I: https://ncert.nic.in/textbook/pdf/kech1ps.zip
The empirical formula gives the simplest whole number ratio of atoms (e.g., CH₂O). The molecular formula gives the actual number of atoms in a molecule (e.g., C₆H₁₂O₆ for glucose). Molecular formula is always a whole number multiple of the empirical formula. They can be the same (e.g., H₂O).
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