Consider the balanced chemical reaction below. When the reaction was
carried out, the calculated theoretical
yield for iron was 365 grams, but the
measured yield was 278 grams. What
is the percent yield?
Fe2O3 + 3CO → 2Fe + 3CO2

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)

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.