A) which are the things you should take care of before, while and after running your analyses? b) what do you need control reactions for? what do you use for a good control reaction? c) sample homogeneity is important for running most of the analyses. why? in which situation might it be advantageous to exploit a sample inhomogeneity? d) why is it useful to read any type of label that comes with an 'unknown' or suspicious substance? e) which information can you find in the pharmacopoeia?

it's c. elements are placed in rows based on how may valencies electrons have.

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.