SOME IMPORTANT DEFINITION IN CHEMISTRY

 These can be further sub-divided as shown below(a)Mixtures :  A mixture contains two or more substancespresent in it (in any ratio) which are called itscomponents. A mixture may be homogeneous orheterogeneous.Homogeneous mixture- in homogeneous mixture thecomponents completely mix with each other and itscomposition is uniform throughout  i.e it consist of onlyone phase. Sugar solution and air are thus, the examples ofhomogeneous mixtures.Heterogeneous mixtures- In heterogeneous mixture thecomposition is not uniform throughout and sometimes thedifferent phases can be observed. For example, grains andpulses along with some dirt (often stone) pieces, areheterogeneous mixtures.Any distinct portion of matter that is uniform throughoutin composition and properties is called a Phase.(b)Pure substances :- A materialcontaining only onesubstance is called a pure substance.In chemistry, a substance is a form of matter that hasconstant chemical composition and characteristicproperties.  It cannot be separated into components byphysical separation methods, i.e. without breakingchemical bonds. They can be solids, liquids or gases.Pure substances can be further classified into elementsand compounds.Element- An element is defined as a pure substance thatcontains only one kind of particles. Depending upon thephysical and chemical properties, the elements are furthersubdivided into three classes, namely (1) Metals (2) Non-metals and (3) Metalloids.Compound- A compound is a pure substance containingtwo or more than two elements combined together in a fixedproportion by mass. Further, the properties of a compoundare completely different from those of its constituentelements. Moreover, the constituents of a compoundcannot be separated into simpler substances by physicalmethods. They can be separated by chemical methods. 4. PROPERTIES OF MATTEREvery substance has unique or characteristic properties.These properties can be classified into two categories –physical properties and chemical properties.4.1 Physical PropertiesPhysical properties are those properties which can bemeasured or observed without changing the identity or thecomposition of the substance. Some examples of physicalproperties are color, odor, melting point, boiling point,density etc.4.2 Chemical propertiesChemical properties are those in which a chemical changein the substance occurs. The examples of chemical propertiesare characteristic reactions of different substances; theseinclude acidity or basicity, combustibility etc.  5. MEASUREMENT5.1 Physical quantitiesAll such quantities which we come across during ourscientific studies are called Physical quantities. Evidently,the measurement of any physical quantity consists of twoparts

6. SOME IMPORTANT DEFINITION

 The mass and weightmass of a substance is the amount of matter present in the same load, which is the force exerted by gravity on an object.  The mass of a substance is constant, while its weight varies from one place to another, the change in gravity.  The SI unit of mass is kilogram (kg).  The SI derivative (unit derived from SI base units) is the newton by weight. The 2 volume volume is the volume of a three-dimensional space, surrounded by some closed boundary, for example, the space that is disjoint (solid, liquid  , Gas or plasma) or in shape.  Businessmen are involved.  Volume is often determined numerically using an SI derived unit, cubic meter.3.3.  The mass density or density of a material is defined as its unit volume.  The most frequently used symbol is (lower case Greek letter rho).  The density of SI unit is iskg m-3.6.4 Temperature Temperature is a physical property of matter that expresses the general assumptions of hot-edge.  There are three common scales for measuring temperature - ° C (° C), ° F (° F) and K (Kelvin).  The temperature on the two scales is related to each other.  The following relation: ° F = 9/5 (°) C) + 32 K = ° C + 273.157.  Law of chemical composition. 1 Law of conservation of mass "In a chemical reaction the mass of the products that form the mass of the reactants is the same mass, that is, the mass is isosceles."  This is a direct consequence of the law of atoms.  This law was put forward by Antonilavioire of constant / fixed ratio in 1789.7.2.  A ratio in which there is a combination of two or more elements, which remains fixed to make the shiver and is independent of the source of the compound.  This law was given by Joseph Proust.7.3 Multiple Ratio Law, a French chemist.  To make two or more compounds of two elements of two elements, the ratio of the mass of one element that combines the Vitha fixed mass of the other element in two compounds is the whole number ratio.  This law was proposed by Daltonin 1803.7.4.  Law of reciprocal ratios When three elements combine with each other's combination of two and form three compounds, the ratio of the mass of the two elements together with the fixed mass is the third and the ratio in which they combine with each parent.  Huh.  Simple whole number ratios for each other.  ThisLaw was given by Richter in 1792.7.5.  Gay Lussac's rule of gaseous volume This law was given in 1808 by Gay Lussack.  He observed that when a combination of gases occurs or is generated in a chemical reaction, they are available in a simple proportion, provided that the algas is at the same temperature.  And pressure.7.6 Avogadro Law.  In 1811, Avogadro proposed that the same amount of gases are at the same temperature and that the molecules must be equal in pressure.