The Solid State .pptx Class 12 Chapter 1 Chemistry

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Diagonal Relationship between Beryllium and Aluminium || Relation between Beryllium and Aluminium

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  Diagonal Relationship between Beryllium and Aluminium The ionic radius of Beryllium (Be 2+) is estimated to be nearly 31 pm; the charge/radius ratio Or e/m ratio is nearly the same as that of the Al 3+ ion. Hence beryllium resembles aluminium in these ways. Some of the similarities are given below: » Like Aluminium, Beryllium(be) is not readily attacked by acids H+ donor because of the formation of an oxide film on the surface of the metal by reacting with oxygen, i.e. they are rendered passive by nitric acid. » Beryllium hydroxide[[Be(OH)4]2] dissolves in excess of alkali to give a beryllate ion, [ Be(OH)4]2– just as aluminium hydroxide[Al(OH)3] gives aluminate ion, [Al(OH)4] » The chlorides of metals beryllium and aluminium have Cl– bridged chloride structure in vapour phase. Both the chlorides are soluble in organic solvents and are strong as Lewis acids They are used as Friedel Craft catalysts. » Beryllium(Be) and aluminium(Al) ions have strong tendency to form complexes, (Be...
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A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of 5.0 m/s². Calculate the initial thrust (force) of the blast.

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Ques : A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of 5.0 m/s². Calculate the initial thrust (force) of the blast. Ans : Mass of the rocket, m = 20,000 kg Initial acceleration, a = 5 m/s2 Acceleration due to gravity, g = 10 m/s2 Using Newton’s second law of motion, the net force (thrust) acting on the rocket is given by the relation: F – mg = ma F = m (g + a) = 20000 × (10 + 5)  = 20000 × 15  = 3 × 10^5 N. 
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Changing Trends And Career in Physical Education || Physical education Chapter 1 || Chapter 1 Changing Trends And Career in Physical Education || Physical education || Notes ||

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1. Meaning and Definition of Physical Education Physical Education is composed of two words Physical and Education. ‘Physical’ means body and ‘Education’ means modification of behaviour thus means Education through the medium of physical Activities. It aims on overall development of human being through participating in various games and sports activities. Modern Physical Education was started in 18 century in Germany. Where Physical Education was an integral part of School Curriculum, Since then many changes have taken place and various aspects have emerged with time.  1.1 Definitions of Physical Education: In fact the basis of the physical education is difficult and very broad changing with time, its meaning also kept changing. Following time, its meaning: According to Charles A Bucher, "physical education is an integral sum part of  the total education process and has its aim in the development of physically, mentally, emotionally and socially fit citizens through the med...
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Why should a magnesium ribbon be cleaned before burning in air?

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Ques 1 : Why should a magnesium ribbon be cleaned before burning in air? Ans 1: Magnesium is very reactive metal like (Na, C a, etc.). When it expose to air it reacts with oxygen to form a layer magnesium oxide (Mg O) on its surface.                  Mg +  O 2 → 2 Mg O This layer of magnesium oxide is quite stable and prevents further reaction of magnesium with oxygen. The magnesium ribbon is cleaned by sand paper to remove this layer so that the underlying metal can be used for the reaction. «« Chapter 1 NCERT Solution                                            Next question »»
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Computer science MCQ questions Class 12 Python

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