HALF LIFES CHEMISTRY PROBLEMS
1)How much of a 888lb sample of Radium-189 Remains after 3 half Lives?

2)If you start with 200g or Uranium-282,How much will remain of 4 half lives?

3)How much of a 750 gram sample of 42K is left after 12.4 hours?

4)How much of an 88 gram sample of 232Th of remains after 4.2x10^10 years?

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.