In the chemical closet, you found an unlabeled vial with a solid piece of an unknown element inside (element Z) You decided to put it in the mass-spec to figure out its atomic mass. The results showed that it has two naturally occurring isotopes, Z-85, and Z-87. Z-85 has a natural abundance of 72.17% and a mass of 84 912 amu Z-87 has a natural abundance of 27 83% and a mass of 86 909 amu. Calculate the average atomic mass and determine the identity of mystery element Z

85.4678

It is Rubidium

Explanation:

A natural abundance of 72.17% and a mass of 84 912 amu

A natural abundance of 27 83% and a mass of 86 909 amu.

Average atomic mass

= 84.912 x .7217 + 86.909 x .2783

= 61.28099+24.18677

= 85.46776

=85.4678

It is Rubidium .

the answer is c

tell me if wrong

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.