Limiting Reagent

The reactant which reacts completely in the reaction is called limiting reactant or limiting reagent. The reactant which is not consumed completely in the reaction is called excess reactant . Question : 3 g of H2 react with 29 g of O2 to form H20.Which is the limiting reagent ? Answer : Thus O2 is…

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Balancing Of A Chemical Equation

Balancing of a chemical equation means making the number of atoms of each element equal on both sides of the equation. The methods of balancing equation are: 1)Hit and Trial Method: The simplest method to balance a chemical equation is by hit and trial method. Step 1 : Write down the correct formula of the reactants…

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Empirical and Molecular Formula

Calculation of percentage composition The percentage of any element or constituent in a compound is the number of parts by mass of that element or constituent present in 100 parts by mass of the compound. Step 1 : Calculate the molecular mass of the compound from its formula by adding the atomic masses of the…

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Dimensional analysis

Any calculations involving the use of the dimensions of the different physical quantities involved is called dimensional analysis. It is used for any one of the following purpose: 1)To convert a physical quantity in one type of units into some other units:The method used is called factor label method or unit factor method. a)First determine…

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Mole concept

Mole Concept | Some Basic Concepts of Chemistry | Class 11      One gram atom of any element contains the same number of atoms and one gram molecule of any substance contains the same number of molecules. The value was found to be 6.022137 × 1023 The value generally used is 6.022 × 1023 . This is called…

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Mole concept in solutions

A solution is defined as a homogeneous mixture of two or more chemically non reacting substances, the relative amount of which can be varied up to a certain limit. If a solution consist of only two components it is called a binary solution. The component present in smaller amount is called solute while the other…

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Atomic and Molecular mass

​As an atom is so small a particle that it cannot be seen or isolated ,therefore it is impossible to determine the actual mass of a single atom by weighing it. The problem was finally solved by Avogadro’s hypothesis.If equal volumes of two different gases are taken under similar conditions of temperature and pressure and…

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Avogadro’s hypothesis

​Berzelius a Swedish chemist, gave a hypothesis called Berzelius hypothesis which states that : Equal volume of all gases under similar conditions of temperature and pressure contain equal number of atoms. For Ex: Hydrogen + Chlorine —————-> 2 Hydrogen chloride gas 1 vol                1 vol      …

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Dalton’s Atomic theory

​John Dalton in 1808 put forward theory known as Dalton’s atomic theory. The main points of this theory are: 1)Matter is made up of extremely small indivisible particles called atoms. 2)Atoms of the same element are identical in all respect i.e. shape ,size and mass. 3)Atoms of different elements have different masses, sizes and also…

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Laws of chemical combination

​Law of conservation of mass This Law was studied by French chemist Antoine lavoisier in 1789 This law states that In all physical and chemical changes ,the total mass of the reactants is equal to that of the products. Or Mass can neither be created nor destroyed. This law is also called as the law…

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Significant figures

​The accuracy of any measurements depends upon the a) accuracy of the measuring device used b) the skill of its operator. If the average value of different measurements is close to the correct value ,the measurement is said to be accurate. If the values of different measurements are close to each other and hence close…

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Physical quantities

​Physical properties are those which can be measured or observed without changing the identity or composition of the substance. For example :Mass ,volume, melting point ,boiling point. Chemical properties are those in which a chemical change in the substance occurs. The measurement of any physical quantity consists of two parts: a)The number b)The unit For…

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Classification of matter

​Matter is defined as anything that occupies space and possesses mass. Classification of matter 1)Physical classification a)Solid b)liquid c)Gases                  Solid                 Liquid                    Gases 1)They have fixed shape and volume They do not have fixed shape but have fixed…

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Importance of chemistry

​Chemistry is defined as that branch of science deals with the study of composition, structure and properties of matter and the changes which the matter undergoes under different conditions and laws which govern these changes. Importance of chemistry 1)Supply of food 1)It has provided chemical fertilizers such as urea ,calcium superphosphate, sodium nitrate, Ammonium Sulphate…

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