A beaker contains 500 ml of 2.40M KNO3 the beaker is left uncovered so that all of the water evaporates. What mass of KNO3 crystals will remain in the beaker when the beaker is dry.

242.4 g

Explanation:

RAM of KNO3=39+14+(16×3)=101

Mass=morality×RAM

101*2.4=242.4

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.