E-Lecture - Important Points
- Chemical reactions are represented by chemical equations.
- The three basic laws of chemical reactions are: the law of conservation of mass, the law of definite proportion and the law of multiple proportions.
- A balanced chemical equation is an equation in which all the number of atoms of reactants and products are equal.
- Chemical reactions are classified into combination, decomposition, single displacement and double displacement reactions.
- Stoichiometry is the quantitative relationship between reactants and products.
- Mass-mass problems, mass-volume and volume-volume problems are the main types of stoichiometric calculations.
- Stoichiometry is the quantitative relationship between reactants and products.
- Mass-mass problems, mass-mole and mole – mole problems are the main types of stoichiometric calculations.
- The mole is the amount of a substance that contains the same number of particles as the number of atoms in exactly 12 g of carbon -12.
- A mole is Avogadro’s number (6.022 × 1023) of particles (atoms, molecules or ions).
- Molar mass is the mass of one mole of atoms, molecules or ionic compounds and expressed by the unit gram per mole (g/mol).
- Percentage composition of a compound is the number of parts by mass of each element in one hundred parts by mass of the compound.
- Molecular formula is the formula that shows the actual number of atoms of each element present in a compound.
- Empirical formula is the formula that shows the number of atoms of each element present in the compound in the lowest possible ratio.
- Some compounds have the same empirical and molecular formula.
- In case of some compounds, the molecular formula is a whole number multiple of the empirical formula.
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