Calculate the change in the standard molar entropy of sulfur trioxide gas, SO3, when it is cooled from a temperature of 100 °C to 10 °C at a constant pressure of 1 bar. The standard molar constant-pressure heat capacity of sulfur trioxide is 50.1 J K-1 mol-1.

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.