c12-Org

Question 1

what are alkanes

Answer 1

alkanes are saturated hydrocarbons, containing only carbon and hydrogen atoms joined together by single covalent bonds

Question 2

how many bonds does an alkane have to other other atoms (what type of bonds)

Answer 2

each carbon atom is joined to 4 other atoms by single covalent bonds called sigma bonds

Question 3

what are sigma bonds

Answer 3

sigma bonds are the result of of the overlap of two S orbitals, one from each bonding atom, each C atom in an alkane has 4 sigma bonds

Question 5

what is the shape and bond angle of alkanes

Answer 5

-tetrahedral arrangement
-109.5 degree bond angle

Question 6

how is crude oil seperated into alkanes

Answer 6

fractional distillation

Question 7

how does the boiling point change as the size of the alkanes increases and why

Answer 7

-as size increases so does the boiling point
-this is because of intermolecular forces

Question 8

how do london forces affect the boiling point as th elength increases

Answer 8

molecules that have a large surface area will form more london forces with other molecules, therefore more energy is required to overcome these forces

Question 9

why do branched isomers have lower boiling points than straight chained isomers

Answer 9

-branched isomers have fewer surface points of contact between molecules of the branched alkanes, giving fewer london forces
-branches get in the way and prevent the branchged molecules from getting as close together as a triaght chain molecule

Question 10

why do alkanes no react with most common reagents

Answer 10

-sigma bonds are strong
-c-c bonds are non polar
- the electronegativity of carbon and hydrogen is so similar that the c-h bond can be considered to be non polar