saturated and unsaturated hydrocarbons

Question 1

why are saturated hydrocarbons called saturated?

Answer 1

because the molecule has reached the maximum carrying capacity for containing hydrogen atoms

Question 2

why are unsaturated hydrocarbons called unsaturated?

Answer 2

because the molecule has not reached the maximum carrying capacity for containing hydrogen atoms (they have double, triple bonds around carbon atoms)

Question 3

what molecular geometry makes up a saturated hydrocarbon?

Answer 3

a tetrahedral arrangement around each carbon atom

Question 4

what molecular geometry makes up an unsaturated hydrocarbon

Answer 4

tetrahedral arrangment and also trigonal planar around each carbon atom

Question 5

why are saturated hydrocarbons less reactive than unsaturated carbons?

Answer 5

saturated hydrocarbons contain only sigma bonds while unsaturated hydrocarbons contain pi bonds as well as sigma bond. with the maximum capacity of hydrogen atom, this makes the saturated hydrocarbon’s molecular geometry symmetrical so the dipole moments cancel each other out (non polar). with the addition of pi bonds, this causes the shape of the unsaturated hydrocarbon to become unsymmetrical therefore would be polar as the dipole moments wouldn’t cancel each other out.

Question 6

why are saturated hydrocarbons solid at room temperature?

Answer 6

the straight shape of the saturated hydrocarbon allows for the chains’ stacking, therefore more intermolecular bonds can be formed (and are stronger, especially dispersion forces).