The molar heat of fusion of iron(II) sulfide (FeS) is 20.9kJ. What mass of melted FeS at its melting point must solidify to release 150.0 kJ of energy?

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.

answeridentity;