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Ask QuestionPosted by Bhoopendra Yadav 5 years, 8 months ago
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Posted by Shyam Kumar 5 years, 8 months ago
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Posted by Muhammad Sarfraz 5 years, 8 months ago
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Meghna Thapar 5 years, 8 months ago
5 chemistry discoveries that changed the world are:
1. The first discovery was penicillin. It was discovered on Friday, September 28 by Alexander Fleming. He discovered it by observing a mould that was mistakenly left out and was growing around a Petri dish.
2. The second discovery was the Haber-Bosch Process. In short, it is the combustion of atmospheric hydrogen with nitrogen to produce ammonia. This played a pivotal role when it was turned into a crop fertilizer, giving consumable plants the ability to intake nitrogen.
3. The third discovery is polythene. From hard hats to plastic bags, it's the most common plastic found in products today. In 1898, Hans von Pechmann discovered something waxy at the bottom of his tube. The funny thing is that he was studying something completely different, making the discovery accidental. He and his fellow scientists studied the substance and found out that it was composed of very long molecular chains. These chains were later termed polymethylene.
4. The fourth discovery would have to go to radiation. The study of radiation took many years. In 1896, Henri Becquerel began studying the properties of x-rays by using naturally fluorescent minerals. He then did an experiment using potassium uranyl sulfate on photographic plates in which he wrapped the plates in black paper and exposed them to sunlight. He originally thought that the uranium would absorb the sun rays in which they would be emitted as x-rays.
5. The final discovery that has played a role in all of our lives in the 21st century is the LCD screen. This dated back to the 1960s in Britain. The British Military wanted new flat screens in vehicles rather than the old bulky and rather expensive cathode ray tubes. This brought up the discussion of Liquid Crystal Displays, or LCDs.
Posted by Abhay Khajuria 5 years, 8 months ago
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Yogita Ingle 5 years, 8 months ago
It is the study of the chemical phenomena that occur at the interface of two surfaces which can be solid-liquid, solid-gas, solid-vacuum, liquid-gas, etc. Some applications of surface chemistry are known as surface engineering. There are various phenomena taking place on the surface of a substance and out of them some are:
- Adsorption
- Heterogeneous Catalysis
- Corrosion
- Crystallization
Posted by Madhu B 5 years, 8 months ago
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Posted by Nirupama Kannan 5 years, 8 months ago
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Bharti Rawat 5 years, 8 months ago
Yogita Ingle 5 years, 8 months ago
Semi-permeable Membrane: Some membranes appear to be continuous but they have minute pores through which small molecules can pass. Such a membrane is called semi-permeable membrane.
Madhu B 5 years, 8 months ago
Posted by Nirupama Kannan 5 years, 8 months ago
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Madhu B 5 years, 8 months ago
Posted by Nirupama Kannan 5 years, 8 months ago
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Yogita Ingle 5 years, 8 months ago
- At a given temperature liquids vaporize. At equilibrium the pressure exertedby the vapour of the liquid over the liquidphase is referred to as vapour pressure.
- According to Raoult’s law, vapour pressure of a volatile component in a given solution ca be defined by pi = pi 0 xi
- In an answer of a gas in a fluid one of the segments is volatile to the point that it exists as a gas and solvency is given by Henry's law which expresses that p = KH x
- Comparing both the equations we get that partial pressure of the volatile component or gas is directly proportional to its mole fraction in solution. Proportionality constant KH differs from p10
- Therefore, Raoult's law turns into a unique instance of Henry’s law in which KH get to be equivalent to p10.
Posted by Krishn Kant 5 years, 8 months ago
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Yogita Ingle 5 years, 8 months ago
(a) Catalyst have no effect on the value of Gibbs Energy (ΔG) of a reaction.
(b) Catalyst lower the value of activation energy (Ea).
Posted by Vivek Chaurasia 5 years, 8 months ago
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Posted by Sunam Kundal 5 years, 8 months ago
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Posted by Sammit Bhoi 5 years, 8 months ago
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Posted by Sabari Rani 5 years, 8 months ago
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Posted by Gaurav Singh 5 years, 8 months ago
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Posted by Totaram Gurjar 5 years, 8 months ago
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Bharti Rawat 5 years, 8 months ago
Yogita Ingle 5 years, 8 months ago
Raoult’s law
- Raoult’s law establishes a quantitative relationship between the partial vapour pressure and mole fraction of a solution.
- This law is only for liquid-liquid solution.
- The law states that for a solution of volatile liquids, the partial vapour pressure (p) of each component in the solution is directly proportional to its mole fraction (x).
- Mathematically, p ∝ x
Or p = p 0x
Where p0 is the vapour pressure of pure component at the same temperature.
Posted by Ssksham Agnihotri 5 years, 8 months ago
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Posted by Kunal Nandal 5 years, 8 months ago
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Yogita Ingle 5 years, 8 months ago
Wohler Synthesis is the conversion of ammonium chunate into Urea .
- This chemical reaction was discovered in 1828 by Friedrich Wohler in an attempt to synthesis ammonium cyanate .
- Ammonium cyanate decomposes to ammonium and cyanic acid which in turn react to produce Urea in nucleophilic addition followed by tautomeric isomerization .
- The Wohler Synthesis is of great significance because for the first time an organic compound was produced from inorganic compound.
Posted by Technical Agnihotri 5 years, 8 months ago
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Posted by Malhaar Mlhr 5 years, 8 months ago
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Meghna Thapar 5 years, 8 months ago
Osmosis is the diffusion of a fluid through a semipermeable membrane. The osmotic pressure of a solution is the pressure difference needed to stop the flow of solvent across a semipermeable membrane. The osmotic pressure of a solution is proportional to the molar concentration of the solute particles in solution.
Posted by Diksha Y 5 years, 8 months ago
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Posted by Madhu B 5 years, 8 months ago
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Yogita Ingle 5 years, 8 months ago
As discussed in the introduction, the Rosenmund reduction is a reaction where acid chlorides are converted into aldehydes by employing hydrogen gas over palladium poisoned by barium sulfate. An example for this catalytic hydrogenation of acyl chlorides forming aldehydes
Posted by Uma Neogi 5 years, 8 months ago
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Vidushi Chaudhary 5 years, 8 months ago
Posted by Sardeep Kumar 5 years, 8 months ago
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Vidushi Chaudhary 5 years, 8 months ago
Tanveerkaurbirring Tanveer Kaur 5 years, 8 months ago
Posted by Tarun Ch 5 years, 8 months ago
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Pawni Chaudhary 5 years, 8 months ago
Tannu Sharma 5 years, 8 months ago
Yogita Ingle 5 years, 8 months ago
Osmotic pressure: The external pressure that must be applied to the solution side to stop the passage of solvent into the solution through a semi- permeable membrane is known as osmotic pressure. It is denoted by π.
π = iCRT
Where,
- π is the osmotic pressure
- i is the van’t Hoff factor
- C is the molar concentration of the solute in the solution
- R is the universal gas constant
- T is the temperature
Posted by Tarun Ch 5 years, 8 months ago
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Madhu B 5 years, 8 months ago
Yogita Ingle 5 years, 8 months ago
The amount of dissolved oxygen in water decreases with rise in the water's temperature. Cold water has more dissolved oxygen per unit area than warm water. This the reason why aquatic animals are more comfortable in cold water than warm water.
Posted by Madhu B 5 years, 8 months ago
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Posted by Armaan Khan 5 years, 8 months ago
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Yogita Ingle 5 years, 8 months ago
Halogens can acts as Strong oxidizing agents because of high electronegativity and high electron affinity which makes them to take electrons very much readily takes electrons from other elements and oxidise other elements.
Decreasing order of Oxidising strength among halogens is : F > Cl > Br > I
Posted by Neha R Gowda 5 years, 8 months ago
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Vidushi Chaudhary 5 years, 8 months ago
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Bhavya ? 5 years, 8 months ago
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