alkanes

Question 1

sigma bonds

Answer 1

C-H and C-C bonds
electron orbitals overlap directly between two atomic nuclei
sigma bonds allow free rotation of atoms at either end

Question 2

C bond angles

Answer 2

every carbon makes four bonds
electron pairs will repel to be as far apart as possible
tetrahedral arrangement - 109.5 degree angles

Question 3

straight chain boiling points

Answer 3

bp increases with chain length
- opp for greater induced dipole-dipole interactions when aligned

Question 4

branched chain bp

Answer 4

branching reduces bp
reduced sa for alignment for induced dipole-dipole interactions

Question 5

reactivity

Answer 5

generally unreactive
high bond enthalpy (high energy required to break bonds)
sigma bonds reduce bond polarity
non polar- cannot form hydrogen bonds-do not dissolve

Question 6

combustion

Answer 6

complete= blue flame
produce CO2 and water
incomplete= orange smoky flame

Question 7

incomplete

Answer 7

pure carbon parties glowing orange
produce= co2, water, pure carbon, hydrocarbons and CO
more likely with longer chains (need more oxygen for complete combustion)

Question 8

effect of CO

Answer 8

binds to haemoglobin more than oxygen
stop body receiving enough oxygen
eventually leads to suffocation