Define Work Done.
Work done is defined as the product of force and displacement. The SI unit of work done is Joule.OR
When force is applied on a object then that covered some distance is known as work.
Work W=F*D
Define Aufbau Principle?
It state's that "the electrons occupy the orbitals of minimum energy first and then they occupy the orbitals of maximum energy".
Chemistry
Laboratory Preparation of Nitrogen Gas
Principle: In the Laboratory Nitrogen gas is prepared by Heating the mixture of sodium nitrite and ammonium chloride then they reacts together and produce nitrogen gas.
Apparatus Required: Round Bottom Flask, cork, stand, Delivery tube, Gas jar, pneumatic trough, Bee-hive shelf,burner.
Chemical Required: sodium nitrite and ammonium chloride.
Theory:
Take the mixture of sodium nitrite and ammonium chloride in the same proportion in the Round Bottom flask. Some water is added to make the solution of mixture. Then the delivery tube is fitted with a round bottom flask with the help of a cork. The apparatus is fitted as shown in figure. The flask is heated gently with a source of heat. After that the gas is produced by the reaction of the chemicals and is collected in the gas jar by download displacement of water. The nitrogen obtained from nitrogenous compounds is about pure which is call chemical nitrogen.
Test of Gas
1. Nitrogen gas is written as N2 and has two nitrogen atoms bonded together with a triple bond. It is the most abundant gas in the atmosphere. It is highly inert and nonreactive to other chemicals.
2. Chemists often use nitrogen gas to create an inert atmosphere for a chemical reaction in a reaction vessel. Due to this inertness, there is no true diagnostic test for nitrogen, but you can distinguish nitrogen from the other two most common atmospheric gasses (oxygen and carbon dioxide) with a couple of simple tests.
3. If a flaming wooden splint or piece of paper is inserted into a tube of gas and the flame immediately goes out, then the gas is nitrogen versus oxygen (oxygen would feed the flame). If a wet piece of pH paper is inserted into a tube of gas and shows no change, then the gas is nitrogen versus carbon dioxide. Nitrogen is pH neutral while carbon dioxide is acidic in water and would turn the paper red.
Finally class 9 First chapter measurement and Force pdf is here please click on the pop of your windows
Electron Sea model of Metals
We have studied that metals lose valence electrons to other
during a chemical reaction to become stable. What type of bond is formed when
two metal atoms are bonded together? How atoms are arranged in a piece of
metal? Why is the force of attraction explained by electron sea model?
Generally, metals have less number of valance electrons and
they have vacant outer electron orbitals. What does this mean for the metal
atoms? How atoms are arranged in a crystal piece of metal? Why does the force
of attraction take place between the atoms? To answer these questions, let's
consider electronic configuration of two metals: aluminium and calcium.
1 Comments
Good
ReplyDeleteIf you have any doubt please text me