PHYSICAL QUANTITIES Physics deals with numerous physical quantities in terms of which the laws of physics are expressed. Volume, speed, force, time, mass, density, temperature, electric current e.t.c are few examples of physical quantities. Physical quantities classified into two categories: BASE AND DERIVED QUANTITIES We can define the base quantities as the minimum number of those physical quantities in terms of which other physical quantities can be defined. Derived quantities are those whose definitions are based on other physical quantities, that is, the base quantities. BASE AND DERIVED UNITS Base quantities are said to have base units and derived quantities have derived units. For example, if displacement (length) and time are chosen to be base quantities, then velocity is a derived quantity
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UNIT OF CONCENTRATION OF SOLUTION Basic terminologies Phase: Every sample of matter with uniform properties and a fixed composition is called a phase. Examples: Sample of water at room temperature and normal pressure exists as a single liquid phase that is all the properties of water sample are same throughout this liquid phase. Mixture of water and small amount of sugar is also the example of phase. However this phase has different properties as compared to pure water sample. But properties of this new phase i.e., water and sugar mixture remains same throughout the sample. Solution: A homogeneous mixture of two or more than two substances is called solution. There are two components of solutions. Solvent: The substance which is present in large quantity in solution is called solvent. Solute: The substance which is present in small quantity in solution is called solute. Example: In aqueous solution of sugar, water is solvent and sugar is solute. Binary ...
STOICHIOMETRY The branch of chemistry which deals with the quantitative relationship of the reactants and the products as given in the balanced chemical equation. A statement that describes a chemical reaction in terms of symbols and chemical formulas is called a chemical equation. Limitations of a chemical equation: The limitations of a chemical equation are as follows: (i) Chemical equation does not show the rate of the reaction. (ii) It does not tell about the conditions necessary for the reaction. (iii) The chemical equation can even be written to describe a chemical change that doesn’t occur. Stoichiometric amounts: The amounts of the reactants or the products as given by the balanced chemical equation are called stoichiometric amounts. 2H 2 + O 2 2H 2 O (i) 2moles ...