Knowledge in Physical Chemistry
Chemistry Notes
Chemistry notes for Btech first semester especially for Guru Gobind Singh Indraprastha University. Must have a look at it!
raghav gautam
Chemistry important questions
Important questions and their solutions for Chemistry subject for the course Btech first semester of Guru Gobind Singh Indraprastha University.
Fuel Chemistry Notes
Fuel notes for the subject of chemistry for first semester of Btech especially made for Guru Gobind Singh Indraprastha University.
Jee main 2019 chemistry paper of resonance
Yaar is the solution of JEE main 2019 chemistry paper by resonance
Soham Sengupta
Hardness of Water
Hardness of waterHardness of water is defined as the property which prevents the lathering or foam formation of soap. This is due to the presence of certain salts of calcium, magnesium and other heavy metals dissolved in water.Hardness is of two types:1. Temporary Hardness2. Permanent Hardness Temporary Hardness:Temporary hardness is caused mainly due to the presence of bicarbonates of calcium and magnesium ions Ca(HCO3 ) 2, Mg(HCO3 )2 will give temporary hardness.· It can be easily removed by boiling of water at 1000 C.· When bicarbonates are decomposed yielding insoluble carbonates which gets deposited as a crust at the bottom of the vessel, water is filtrated.· Temporary Hardness can be largely removed by the boiling of water on boiling bicarbonates converts into carbonates which are insoluble.· They can be removed by filtration.Ca(HCO3)2 → CaCO3 + H2O + CO2Permanent Hardness:Permanent Hardness is due to the presence of dissolved chlorides and sulphates of calcium, Magnesium and other metals. The salts responsible for permanent hardness are CaCl2, MgCl2, CaSO4, MgSO4· Permanent Hardness cannot be removed by boiling.· Permanent Hardness can be removed by using chemical agents.· Total hardness of water = Temporary hardness + Permanent hardnessCauses of Hardness of Water:With respective sources of water impurities found are different. Irrespective of sources water contains suspended particles and suspended solids. Solids may come from flowing water and it may contain organic materials coming from plants and animals.· Colloidal particles are because of traces of oils by flowing of water.· Disease causing micro-organisms are the biological impurities which are obtained from dead organisms and eggs of the insects.The major causes of hardness are :The natural water is usually contaminated by different types of impurities.1. Physical impurities2. Chemical impurities3. Biological impurities4. Colloidal impurities
Patri Divya Chandana
Water and its Importance
Water and its importanceSources of Water:1. Rain Water:Rain water comes from the clouds to the earth by dissolving some gases and minerals.2. Sea Water:Sea water mostly contains minerals and dissolved salts but it cannot be used for agricultural purpose. It can be used for industrial and household purposes.· In some countries sea water is used after desalination for drinking and domestical purposes.3. Underground water:One of the main source of water is underground water. It may contain many dissolved salts but it can be used for industrial, agricultural and household purposes.· It contains calcium, magnesium and in some cases silicon. These salts get filtered while penetrating into the soil by the layers of sand and rock.· The crust layers play a major role in purifying rain and river water.· Ground water is pure because water goes deep into the earth. It dissolves salts because of increase in temperature. It accumulate most of the water containing salts like calcium bi carbonate, magnesium bi carbonate, calcium chloride, magnesium chloride.4. Rivers, Lakes and Ponds:Rivers are the source of flowing pure water. The water from rivers penetrate into the earth’s crust to form underground water. River water doesn’t contain many impurities and it is considered as fresh water.Lakes and Ponds are the source of stable water used on regular basis. Many people depends on lakes and ponds for their survival like agriculture, fishing etc.Usage of Water:Water plays a major role in earth’s life style.Water is used for the following:1. Drinking2. Cleaning3. Domestic Purposes4. Agriculture5. Power Generation6. Fishing7. Aquaculture8. Salt Production9. Industrial usage:· Textile Industries· Paper Industries· Pharmaceutical Industries· Sugar Industries· Beverage IndustriesThe water is playing a vital role in our day to day life. Water covers 71% of earth’s surface mostly in seas and oceans. Small portions of water occur as ground water (1.7%). In the glaciers and ice caps of Antarctica and Greenland (1.7%), and in the air as vapor, clouds and precipitation (0.001%).Approximately 70% of fresh water used by human goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. But the availability of fresh water is only 17% on the earth. It should not be polluted and is used properly for preserving it to future generations.
Polymers
A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Due to their broad range of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life.
Arun Thomas
Corrosion
Corrosion is a natural process that converts a refined metal into a more chemically-stable form such as oxide, hydroxide, or sulfide. It is the gradual destruction of materials by chemical and/or electrochemical reaction with their environment
The Phase Rule
The phase rule is a general principle governing systems in thermodynamic equilibrium. If F is the number of degrees of freedom, C is the number of components and P is the number of phases, then { F=C-P+2. F=C-P+2.} It was derived by Josiah Willard Gibbs in his landmark paper titled On the Equilibrium of Heterogeneous Substances, published in parts between 1875 and 1878. The rule assumes the components do not react with each other.
Chemical Equilibrium
In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.
EneDiols
An enediol is an alkene enol with a hydroxyl group attached to both carbon atoms of the carbon double bond. An example: Catechol is an enediol. Two of the hydroxyl groups are attached to one of the carbon double bonds in the benzene ring
Surface Tension
Surface tension is the tendency of fluid surfaces to shrink into the minimum surface area possible. Surface tension allows insects, usually denser than water, to float and slide on a water surface.