petroleum and alkanes mini test

Question 1

are alkanes generally reactive

Answer 1

no

Question 2

whats the trend in boiling points with alkanes

Answer 2

the longer the carbon chain the higher the boiling point due to stronger van der waals forces between molecules

Question 3

whats the trend with boiling points and branched hydrocarbons

Answer 3

the more branches the lower the boiling point due to the molecules having weaker van der waals
forces

Question 4

how is crude oil and natural gas formed

Answer 4

the slow decay of
marine biodiversity over millions of years under heat and pressure in the absence of
air

Question 5

what physical property does fractional distillation work by

Answer 5

the different boiling points of the hydrocarbons

Question 6

whats the process of fractional distillation

Answer 6

• the crude oil is vaporised
  -the vapour enters the fractioning
  column (hottest at
  bottom - coolest at top)
  -the vapour rises through and different hydrocarbons condense
  at different levels
  -the larger the molecule the lower down it condense

Question 7

whats the trend in physical properties as the carbon chain gets
longer

Answer 7

-becomes more viscous
-less volatile
-harder to ignite
-higher boiling
points

Question 8

whats the order of fractions

from the top

Answer 8

Fancy    fuel gasses
Geese    gasoline
Nose       naptha
Ketamin  kerosene
Daily        deisel
Rad           residue

Question 9

what are the two kinds of crackig

Answer 9

thermal cracking and catalytic cracking

Question 10

what is cracking

Answer 10

the breakdown of long chain alkanes

into short chain alkanes

Question 11

describe the conditions

for thermal cracking

Answer 11

900 degress celsius
70 atm
produces alkenes

Question 12

describe the coniditions

for catalytic crackig

Answer 12

450degrees
1-2 atm
zeolite catalyst
motor fuelsare the product

Question 13

what is reforming

Answer 13

turning straight chain hydrocarbons into branches or cyclical so they can burn better and be used as more efficient fuels

Question 14

whats the complete equations for complete combustion

Answer 14

CH4 + 2O2 ——>CO2 + 2H2O

Question 15

whats the equation for incomplete combustion

Answer 15

2CH4 + 3O2 —-> 2CO + 2H2O