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                                                             1st Year Important Questions Q Define the Thermo-Chemistry ? The branch of chemistry which deal with the study of heat changes accompanying the physical or chemical reaction is called the thermochemistry. It deals with the amount of heat envolved or absorbed during the chemical reaction. Q Different between spontaneous and no spontaneous reactions. Spontaneous Reaction :                                     The natural irreversible and uni directional process taking place on its without external assistance moving from non equilibrium to equilibrium state Example Water flow from high level to the lower level. .  Non Spontaneous Reaction : The reverse of spontaneous process which does not take place on its own and hot occurring in nature. Example : Pumping of water uphill. Q Differentiate between the exothermic and endothermic reactions.  Exothermic Reaction:                                These are the thermochem

                                                         Important Questions Q Bond Distance Is the Compirising distance between the two atoms. Ans: When two atoms approach each other forces of attractions and repulsion operate simultaneously. When reached at a certain definite distance the forces o attraction are maximum and potential energy of the system is minimum. If they are brought further closer, the repulsive forces begin to increase and increase the potential energy of the system. Since they have a minimum energy at a certain distance called the bond distance at which they compromise with each other  to have the minimum energy and so bond distance is the compromise distance. Q Pi bonds are more diffuse than the sigma bond. Ans: Sidma bond is formed by the head to head overlapping of half filled atomic orbitals and the electronic density is smmetrical around the nuclear axis whereas the pi bond is formed by the side wise overlapping of two half filled atomic orbitals and

                                                        Important Questions Q Why it is necessary to reduce the pressure inside the discharge tube to get cathode rays ? Ans: The conductance of electricity trough discharge tube does not occur at ordinary pressure because the molecules gas inside the tube hinders the movement of electrons between the electrodes therefore the number of molecules inside the tube is reduced by decreasing the pressure to get the cathode rays. Q How positive rays are produced? Ans:  The positive rays are produced when high speed of cathode rays strike the molecules of a gas enclosed in the discharge tube. They knock out electrons from the gas molecules and positive ions are produced which start moving towards the cathode thus giving rise to the positive rays.                            M+ e-         ------------> M + 2e- Q Whichever the gas used in the discharge tube the nature of cathode rays remains the ame why ? Ans: Cathode rays are emitted fr