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
Posts
CONCENTRATION UNITS OF SOLUTIONS There are various types of concentration units of solutions. They are as following: (1) Percentage composition (2) Molarity (M) (3) Molality (m) (4) Normality (N) (5) Mole fraction (X) (6) Parts per million (ppm) (1) PERCENTAGE COMPOSITION The parts of solute dissolved in 100 parts of solution is called percentage composition of solution. The amounts of solute and solvent can be expressed in percentage composition by four different ways. (a) Percentage weight / weight (b) Percentage weight / volume (c) Percentage volume / weight (d) Percentage volume / volume. (a) Percentage Weight / Weight: It is the weight of a solute dissolved per 100 parts by weight of solution. or number of grams of solute dissolved per 100g of solution is called %W/W. Example: 5% w/w sugar solution means 5 g of sugar is dissolved in 95g of solvent say water. Total mass of solution is 100 g. Formula: % by weight ...