Educational Revolution

A simple solution is made of two substances: one is the solute and the other solvent. Mole fraction, X, of solute is defined as the ratio of the number of moles of solute and the total number of moles of solute and solvent.   Thus, If n represents moles of solute and N number of moles of solvent, Notice that mole fraction of solvent would be, Mole fraction is unit less and

                           It is the weight of the solute as a percent of the total weight of the solution. That is, For example , if a solution of HCl contains 36 per cent HCl by weight, it has 36 g of HCl for 100 g of solution.

The concentration of a solution is defined as: the amount of solute present in a given amount of solution. Concentration is generally expressed as the quantity of solute in a unit volume of solution. A solution containing a relatively low concentration of solute is called dilute solution . A solution of high concentration is called concentrated solution .                                                              Quantity of solute                               Concentration = -----------------------------                                                             Volume of solution WAYS OF EXPRESSING CONCENTRATION There are several ways of expressing concentration of a solution:      (a)  Percent by weight      (b)   Mole fraction      (c)  Molarity      (d)  Molality      (e)  Normality

The common solutions that we come across are those where the solute is a solid and the solvent is a liquid. In fact, substance in any three states of matter (solid, liquid, gas) can act as solute or solvent. Thus there are seven types of solutions whose examples are listed in Table 14.1. of the seven types of solutions mentioned in Table 14.1

A solution is a homogeneous mixture of two or more substances on molecular level. The constituent of the mixture present in a smaller amount is called the Solute and the one present in a larger amount is called the Solvent. For example, when a smaller amount of sugar (solute) is mixed with water (solvent), a homogeneous solution in water is obtained. In this solution, sugar molecules are uniformly dispersed in molecules of water. Similarly, a solution of salt (Na+ Cl–) in water consists of ions of salt (Na+, Cl–) dispersed in water. Types of Solutions (According to concentration or quantity of solute) 11.     Dilute solution (Low solute)          It is a solution which has a little bit of solute. 22.     Concentrated solution(High solute)                    It is a solution which has a lot of solute.                                                    33.     Saturated solution (High+ solute)             A stage of solution when the amount of solute is e

(1) Additive Property When a property of a substance is equal to the sum of the Corresponding properties of the constituent atoms, it is called an additive property . For example, molecular mass of a compound is given by the sum of the atomic masses of the constituent atoms. (2) Constitutive Property A property that depends on the arrangement of atoms and bond structure, in a molecule, is referred to as a constitutive property . Surface tension and viscosity and optical activity are examples of constitutive property. (3) Additive and Constitutive Property An additive property which also depends on the intermolecular structure is called additive and constitutive property. Surface tension and viscosity are such properties. (4) COLLIGATIVE PROPERTIES Colligative Properties (Greek colligatus = Collected together). A colligative property may be defined as one which depends on the number of particles in solution and not in any way on the size or chemical nature of

Forces:-    There are two types of forces between molecular. 1.       Intramolecular force 2.     Intermolecular force Intramolecular force:-                             A force within a molecular is called intramolecular force. I.       Ionic bond     II.    Covalent bond Intermolecular force:- Intermolecular forces in liquids are collectively called van der Waals forces . These forces are essentially electrical in nature And result from the attraction of charges of opposite sign. The principal kinds of intermolecular attractions are: (1) Dipole-dipole attractions (2) London forces (3) Hydrogen bonding. The relative size of these interactions is important so the relative effects are understood. Clearly normal covalent bonds are almost 40 times the strength of hydrogen bonds. Covalent Bonds are almost 200 times the strength of dipole-dipole forces, and more than 400 times the size of London dispersion forces. DIPOLE–DIPOLE ATTRACTION

             Anything that has definite volume but not definite shape is called a Liquid. “A collection of molecules held close to each other and executing random motion through intervening spaces.“ *  Properties of Liquid:-   (General) 1.        Definite volume  2.     Indefinite shape 3.      Contact on cooling 4.     Expand on heating                      5.      Incompressible 6.     Surface tension 7.      Viscosity 8.     Capillary action 9.     Vapour pressure 10.       Density 11.    Diffusion

Make a plan:- • Draw up a study timetable that takes into account your energy levels at different times of the day, and stick to it. • Divide your work into logical sections that have a beginning and an end. Our brains are holistic, so you’ll find it easier to work on something that forms a whole, rather than something that's left hanging midway. Set goals for each study session:- • Before you begin studying, take a few minutes to think about what you’ll achieve. • Write down your goals for the study period. For example: ‘Summaries pages 40-65 ’or ‘complete the outline of Assignment 1’. • Set yourself a time limit before you start. For example: 'I’ll summaries Chapter 2 in 40 minutes'. By doing this, you're setting yourself a goal and your subconscious mind will start working on completing the task in the time available. Collect revision materials before you begin studying:- Collect revision material before when you start studying is one of the