A student placed a small amount of baking soda in a watch glass. When 15 drops of vinegar were added, the solution began fizzing. The watch glass was placed on a warm hot plate to evaporate the liquid. The solid, white crystals remaining after evaporation were different in appearance than the baking soda.
Part A: Which observation most likely indicated that a chemical change had occurred?
Part B: Why were the remaining crystals in the watch glass different than the original baking soda crystals?

elements make up everything, and they combine to make compounds.

the answer is c

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.