WHY CANT I

Thursday, September 08, 2005 , 6:15 PM

ha.. life is neva easy.. tats wat they all say.. well its true.. i have been studyin for the past few hours alreadi.. Ai!!! lets see wat i can recall.. okay.. how do we carry out fractional distillation of the air.. hmmm...1st.. we cool the air.. den freeze the water vapour and the carbon dioxide.. den removed it.. next.. the compressed air is allowed to expand suddenly... thus, the air cools. this principle is used to liquidify the air.. the air is compressed with huge pumps and allowed to expand several times... the liquid air is den distilled in a fractional distillation.. nitrogen with the lowest boiling pt will come out at the top.. followed by argon, oxygen krypton and xenon.. haha.. i managed to remember. ohhhh.. its a good sign..wat abt water purification.. 1st the water is collected from the reservoirs den it is treated with chemicals such as aluminium sulphate ( alum) to make most of the small solid particles suspended in the water to lump together to form larger lumps... other chemicals like calcium hydroxide is also added to react with metal ions to form insoluble metal hydroxide.. the water is den pass through the sedimentation tank to allow the larger solid particles to settle down and be removed.. it is den filter to remove the remainin solid particles... chlorination is den carried out to kill harmful bacteria and to keep the water sterile.. tiny amt of fluorine is also added to protect our teeth frm decay..