organic chemistry

Question 1

what is the general formula for an alkane?

Answer 1

CnH2n+2

Question 2

how is crude oil formed and where is it found?

Answer 2

formed over millions of years from the remains of plankton buried in mud, and is found in rocks

Question 3

viscosity

Answer 3

thickness of a fluid

Question 4

fluids with a high viscosity flow _____

Answer 4

slowly

Question 5

the molecules of hyrdocarbons become _____ viscous as they get _____.

Answer 5

more viscous
larger

Question 6

the boiling points of short chain hydrocarbons are

Answer 6

lower than room temperature

Question 7

short chain hydrocarbons are _____ flammable because

Answer 7

very

they have low viscosity

Question 8

fractional distillation of crude oil

Answer 8

1. the crude oil is heated to a very high temperature, causing it to boil
2. the hydrocarbons evaporate and become gas
3. the vapour is fed up the distillation column
4. the column is hotter at the bottom and cooler at the top, the vapours rise up it
5. they condense when they reach their boiling points and are removed once they do this
6. this continues for those that condense further up the column

Question 9

long chain hydrocarbons have _____ boiling points, so are removed from the _________

Answer 9

high
bottom of the column

Question 10

short chain hydrocarbons have very _______ boiling points, they do not ______ but are extracted as _____

Answer 10

low
condense
gases

Question 11

feedstock

Answer 11

a chemical that is used to make other chemicals

some hydrocarbons are used as this

Question 12

alkene

Answer 12

has at least one double bond between carbon atoms

Question 13

long chain hydrocarbons do not make good ______ because they are not very ______

Answer 13

fuels

flammable

Question 14

cracking

Answer 14

the breaking down of longer chain molecules to make smaller, more useful ones

Question 15

catalytic cracking

Answer 15

uses high temperature and a catalyst

Question 16

steam cracking

Answer 16

uses high temperature and steam

Question 17

why are alkenes useful?

Answer 17

they are used to make polymers, and as a starting material for other useful chemicals as well

Question 18

alkene test

Answer 18

uses bromine water, which is shaken and turns colourless if an alkene is present

Question 19

cracking equations must have…

Answer 19

must have the same number of hydrogen and carbon atoms on both sides