Acid etilen diaminotetra acetic (EDTA) ký hiệu H4Y có các pK1 g pK4 lần lượt như sau: 2.0; 2.7; 6.3; 10.3. Tính pH của dung dịch khi Ca = 0.01 M.
Tính nồng độ cân bằng của tất cả các cấu tử với Ca = 0.01M ở pH = 10

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.

they are called fossil fuels