Petro Chemicals and polymers

Question 1

What are Alkanes?

Answer 1

Alkanes are saturated hydrocarbons, connected by a single bond. C-C
General formula Cn H(2n+2)

Question 2

What are alkanes?

Answer 2

Alkenes are unsaturated hydrocarbons with a double bond. C=C

General formula is Cn H(2n)

Question 3

What are Alkynes?

Answer 3

Alkynes are unsaturated hydrocarbons with a triple bond.

General formula is Cn H(2n-2)

Question 4

What is hydrocarbon?

Answer 4

A compound of hydrogen and carbon.

There are two types of hydrocarbons; saturated and unsaturated.

Question 5

What are the three main fossil fuels?

Answer 5

• coal
• natural gas
• crude oil

Question 6

How is crude oil formed?

Answer 6

Crude oil is formed from prehistoric marine creatures that died and sank to the sea bed. They were covered with mud and with high pressure and temp the organic material turned into hydrocarbons, its then pressed out into the pores of rocks.

Question 7

How were all the fossil fuels roughly formed? And what are they made from?

Answer 7

They all formed from the earths crust from once living material.
Coal is from fossil plant material where as crude oil and natural gas come from once living marine micro-organisms.

Question 8

What does catalytic cracking do?

Answer 8

Large molecules are separated into smaller ones. All cracking reactions produce an alkane with a shorter chain than the original, and a short chain alkene.
Or two or more alkenes and hydrogen.

Question 9

How is coal formed?

Answer 9

Coal is made up of a mixture of naturally occurring compounds. Peat is the first step of coal forming.
Heat and and pressure over long periods form lignite the harder types of coals.

Question 10

How is natural gas or bio gas formed?

Answer 10

Methane is produced naturally under a range of circumstances. Anaerobic bacteria helped helped decompose organic matter under geological conditions to produce natural gas.

Question 11

What are all the alkanes?

Answer 11

Methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane.

Question 12

How is petrol obtained from crude oil?

Answer 12

When tectonic plates shift, earths crust folds, the crude oil builds up and oil wells are used to extract the oil.

Question 13

How can you test for an alkene?

Answer 13

The bromine test can be used to see if an alkene is present. Because of its double bond it will react with bromine and decolourise it, unlike alkanes that cannot.

Question 14

What colour are Alkanes?

Answer 14

Alkanes are usually colourless unless done deliberately. Industries will usually change the colour of alkanes for safety reasons. This can help distinguish leaded from unleaded petrols. Prevents mishaps from selecting the wrong fuel.

Question 15

How does the length of an alkane effect is viscosity and boiling point?

Answer 15

When swirling an alkane in a flask the faster it goes the shorter the alkane chain.

Question 16

What trend is evident in the viscosity of alkanes?

Answer 16

The viscosity of alkanes increases with molecule length. This happens for the same reason as the boiling point: there is a stronger attraction between atoms when they increase in size.

Question 17

WHy do longer length molecules have higher boiling points?

Answer 17

Longer chain molecules have higher boiling points because longer chain molecules become wrapped around and enmeshed in each other. More energy is needed to separate them than short chain molecules which have only weak forces of attraction for each other.

Question 18

Why are Alkanes insoluble in water?

Answer 18

Alkanes are nonpolar and water is polar. Nonpolar and polar do not mix, therefore water and alkanes do not mix.

Question 19

Why are alkenes more reactive than alkanes?

Answer 19

The double bond of alkenes allows for additional reactions to occur. This is also known as addition polymerization.

Question 20

What are Polymers made up of?

Answer 20

Made up of small repeating units called monomers.

A polymer with only one kind of repeating polymer is called a hyper polymer. Otherwise the are called copolymers.

Question 21

How does addition polymerization work?

Answer 21

The double bond of alkenes are broken and other atoms may attach to the carbon atoms. High temp, pressure and a catalyst needed.

Question 22

What is the process used to seperate crude oil?

Answer 22

Fractional distillation.

Question 23

What residue is left at the end of the fractional distillation process?

Answer 23

Bitchimen.

Question 24

How is petrol obtain from crude oil?

Answer 24

Distillation: Is heated at a temp (350-400c), then the crude oil vapours rise inside the column, depending on their boiling points and number of carbon atoms The lighter ones will stay at the top whereas the heavier ones will go to the bottom. This process breaks the bond from hydrogen and carbon chains.

Question 25

With all the cars producing extreme amounts of CO2, why is the levels of O2 and CO2 able to remain constant?

Answer 25

The levels of CO2 remain constant because plants and trees are continually converting CO2 into O2, via photosynthesis.

Question 26

Why is carbon monoxide dangerous?

Answer 26

With out the 2 oxygens present, the single oxygen attaches to human hemoglobin, its then transported around the body but the cell can no longer combust and will die.

Question 27

WHat harmful effects does sulphur dioxide have to the environment?

Answer 27

Its a pollutant from burning coal. It causes acid rain and accelerated corrosion of buildings.

Question 28

Which of the following hydrocarbons would rapidly decolourise bromine solution?

a) Propene
b) Propane
c) Cyclopropane

Answer 28

a) propene: because it is an alkene and they decolourise bromine.