Sunday, May 15, 2011
Reflection on the term 2 science test
Ace on sulfuric acid.
Q: More Sulfuric acid, H2SO4, is made in the United States than any other chemical. Research on the production and uses of sulfuric acid and write a report on your findings.
What is sulfuric acid? Sulfuric acid is a extremely dangerous and oily acid. It has a melting point of -2 C and a boiling point of 327 C. When you are mixing acid to water stir it slowly, much heat is generated with Sulfuric acid. It is one of the cheaper acids in the world. Pure and concentrated sulfuric acid is does not occur naturally due to its affinity to water. It is also a part of acid rain that is formed due to atmospheric oxidation of sulfur dioxide in presence of H2O.
Sulfuric acid is the product of the U.S. chemical industry produced in largest quantity in terms of mass. About 40 million tons are produced annually. Sulfuric acid can be used in many places like removing rust. The following are some common uses.
Manufacture of Sulfuric acid:
There are two major processes (lead chamber and contact) for production of sulphuric acid, and it is available commercially in a number of grades and concentrations. The lead chamber process, the older of the two processes, is used to produce much of the acid used to make fertilizers; it produces a relatively dilute acid (62%–78% H2SO4). The contact process produces a purer, more concentrated acid but requires purer raw materials and the use of expensive catalysts. Some sulphuric acid is also made from ferrous sulphate waste solutions from pickling iron and steel and from waste acid sludge from oil refineries.
Lead Chamber Process
In the lead chamber process hot sulphur dioxide gas enters the bottom of a reactor called a Glover tower where it is washed with nitrous vitriol (sulphuric acid with nitric oxide, NO, and nitrogen dioxide, NO2, dissolved in it) and mixed with nitric oxide and nitrogen dioxide gases; some of the sulphur dioxide is oxidized to sulphur trioxide and dissolved in the acid wash to form tower acid or Glover acid (about 78% H2SO4). From the Glover tower a mixture of gases (including sulphur dioxide and trioxide, nitrogen oxides, nitrogen, oxygen, and steam) is transferred to a lead-lined chamber where it is reacted with more water. The chamber may be a large, boxlike room or an enclosure in the form of a truncated cone. Sulphuric acid is formed by a complex series of reactions It condenses on the walls and collects on the floor of the chamber. There may be from three to twelve chambers in a series. The acid produced in the chambers, often called chamber acid or fertilizer acid, contains 62% to 68% sulfuric acid. After the gases have passed through the chambers they are passed into a reactor called the Gay-Lussac tower where they are washed with cooled concentrated acid (from the Glover tower); the nitrogen oxides and unreacted sulphur dioxide dissolve in the acid to form the nitrous vitriol used in the Glover tower. Remaining waste gases are usually discharged into the atmosphere.
Sulfuric acid is prepared industrially by the reaction of water with sulfur trioxide, which in turn is made by chemical combination of sulfur dioxide and oxygen either by the contact process or the chamber process. The lead chamber process is used to produce much of the acid used to make fertilizers. It produces a relatively dilute acid (62% - 78%). The contact process produces a more concentrated acid but requires purer raw materials and the use of expensive catalysts. Some sulfuric acid is also made from ferrous sulfate waste solutions from pickling iron and steel and from waste acid sludge from oil refineries.
Use of Sulfuric Acid
The uses of sulfuric acid are so varied that the volume of its production provides an approximate index of general industrial activity. Its main use is in phosphate fertilizer production, both superphosphate of lime and ammonium sulfate. It is widely also used to manufacture chemicals, e.g., in making hydrochloric acid, nitric acid, sulfate salts, synthetic detergents, dyes and pigments, explosives, drugs, other acids, parchment paper, glue and wood preservatives. It is used in the purification of petroleum to wash impurities out of gasoline and other refinery products. Sulfuric acid is used in processing metals, e.g., in pickling (cleaning) of metal, electroplating baths, nonferrous metallurgy. Rayon is made with sulfuric acid. In one of its most familiar applications, it serves as the electrolyte in the lead-acid storage battery commonly used in motor vehicles (acid for this use, containing about 33% H2SO4 and with specific gravity about 1.25, is often called battery acid).
Use of Sulfuric Acid
Sulphuric acid is one of the most important industrial chemicals. More of it is made each year than is made of any other manufactured chemical; more than 40 million tons of it were produced in the United States in 1990. It has widely varied uses and plays some part in the production of nearly all manufactured goods. The major use of sulphuric acid is in the production of fertilizers, e.g., superphosphate of lime and ammonium sulphate. It is widely used in the manufacture of chemicals, e.g., in making hydrochloric acid, nitric acid, sulphate salts, synthetic detergents, dyes and pigments, explosives, and drugs. It is used in petroleum refining to wash impurities out of gasoline and other refinery products. sulphuric acid is used in processing metals, e.g., in pickling (cleaning) iron and steel before plating them with tin or zinc. Rayon is made with sulphuric acid. It serves as the electrolyte in the lead-acid storage battery commonly used in motor vehicles.
Ammonium sulphate
It is formed by reacting synthetic ammonia and sulfuric acid. It is an important nitrogen fertilizer. It is commonly used as an artificial fertilizer for alkaline soil. It is also used as agricultural spray adjuvant for water soluble insecticides, herbicides, and fungicides. As a flame retardant, it lowers the combustion of a material.
Removing rust
As it is very corrosive and cheap, it is commonly used with Hydrochloric acid in removing rust. However, since it is highly corrosive, it tend to corrode the metal together with the rust. Therefore, other acids like ethanoic acid are used as they are not so corrosive.
Hazards
Concentrated Sulfuric acid is very corrosive to everything, including skin. It can cause bad burns if you get it on yourself. Even tiny microdroplets that you can barely feel start itching until you get it rinsed off with water. It is very reactive with many chemicals. It is used to digest organic stuff down to elemental states, only the elemental ions are left. It reacts violently with water unless lots of water is used. It gets very hot very fast. When it becomes hot, it gives off a harmful gas that is corrosive to breathe or let it touch the skin.
http://ibchem.com/IB/ibnotes/full/ope_htm/sulphuric%20acid.htm
http://chemicalland21.com/industrialchem/inorganic/sulfuric%20acid.htm
Science for fun
I attended the science for fun course with Josiah and Pei Yu. At first i thought that it would be something like a lecture and we had to take notes or something like that. But after I entered the course, i realised it was doing experiments and other interesting stuff. The first experiment that we did was the Hand Boiler. When we squeeze the bulb containing a liquid, the liquid rises to the top of the bulb. Another experiment i like is the Oobleck. It is an example of a non-Newtonian fluid. It can act like a liquid when held loosely in your hand but it can also act like a solid if you apply force on it. When I slowly put my hand into the Oobleck, my hand sinks into it like a liquid. However when we apply force on it, it becomes as hard as a solid. I felt very fascinated with it as I have never encountered anything like that before.
Quicksand is also a non-Newtonian fluid. When undisturbed, it appears to be solid ("gel" form), but when it is disturbed like when a person attempts to walk on it, there is a sudden decrease in its viscosity (a measure of the internal resistance of a fluid). Then the water and sand in the quicksand separate and dense regions of sand sediment form; it is because of the formation of these high volume fraction regions that the viscosity of the quicksand seems to increase suddenly. Someone stepping on it will start to sink. To move within the quicksand, a person or object must apply sufficient pressure on the compacted sand to re-introduce enough water to liquefy it. The forces required to do this are quite large: to remove a foot from quicksand at a speed of 0.01 m/s would require the same amount of force as "that needed to lift a medium-sized car.”
Because of the higher density of the quicksand, it would be impossible for a human or animal to completely sink in the quicksand, though natural hazards present around the quicksand would lead people to believe that quicksand is dangerous. In actuality the quicksand is harmless on its own, but because it greatly impedes human locomotion, the trapped person is normally harmed by other factors like solar radiation or dehydration.