Test 1 – Organic Chemistry Flashcards by Grace McGeechan

Finite resources are

no longer being made or are being made much more slowly then they are being used. This means that they will run out

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Fossil fuels were formed from

biomass ( plankton and other living organisms) that sink to the sea flooor when they die. They are compressed over millions of years under layers of sediment and mud and form fossil fuels; coal, oil and natural gas

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feedstock

a raw material used to supply or fuel a machine or industrial process

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General formula of alkanes

CnH2n+2 where n is the number of carbon atoms in the molecule.

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Crude oil
is

a
finite
resource that is found in the Earth’s crust. It is the remains of
organisms
that lived and died millions of years ago - mainly plankton which was buried in mud.

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Crude oil is a ( structure wise)

complex
mixture
of hydrocarbons. The carbon atoms in these molecules are joined together in chains and rings

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Crude oil is an important source of:

fuels
such as petrol, diesel, kerosene, heavy fuel oil and liquefied petroleum gases

feedstock
for the
petrochemical
industry

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Other useful substances made from compounds found in crude oil include:

solvents

lubricants

detergents

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The
alkanes
form a

homologous series

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Like all homologous series, the alkanes:

have the same
general formula
differ by CH2 in
molecular formulae
from neighbouring
compounds
show a gradual variation in physical
properties
, such as their
boiling points
have similar chemical properties

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homologous series

A ‘family’ of organic compounds that have the same functional group and similar chemical properties.

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The alkanes are saturated hydrocarbons:

ydrocarbons
, because they are compounds containing hydrogen and carbon only

saturated
, because their carbon atoms are joined by C-C single bonds

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fractional distillation
is used

to separate
crude oil
into simpler, more useful
mixtures
. This method can be used because different
hydrocarbons
have different
boiling points
.

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During the fractional distillation of crude oil:

heated crude oil enters a tall
fractionating column
, which is hot at the bottom and gets cooler towards the top

vapours
from the oil rise through the column
vapours
condense
when they become cool enough
liquids are led out of the column at different heights
different liquids will all have different bpts so will evaporate at different temperatures the liquid with lowest bpt evaporates first

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Naming thing

my elephant poos bricks
methane
ethane propane and butane

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key points for small molecules in a fraction-ating column

low boiling points
very volatile
flows easily
ignites easily

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key points for big molecules in a fraction-ating column

high boiling points
not very volatile
doesnt flows easily
does not ignites easily

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Bitumen is used for

roads and roofs

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Heavy fuel oil is used for

fuel for some ships and power stations

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Diesel is used for

fuel for some cars and trains

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kerosene is used for

fuel for some air-crafts

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petrol is used for

fuel for cars

liquified petroleum gases used for

fuel for domestic heating and cooking

One way to remember the names of the fractions is:

Lazy Penguins Keep Drinking Hot Beer.
liquified petroleum
petrol
kerosene
Diesel
Heavy fuel oil
Bitumen

Each crude oil fraction contains a mixture of -------------- . The ---------- in a fraction are mostly ---------- called -----------

hydrocarbons repeat alkanes

Alkanes have similiar but not identical :

numbers of hydrogen and carbon atoms in their molecules boiling points ease of ignition viscosity

Hydrocarbon fuels can undergo-------- combustion or ------- combustion depending on the amount of -------available.

complete incomplete oxygen

Complete combustion of a hydrocarbon fuel happens when there is a andproduces

good supply of oxygen in air. Carbon and hydrogen atoms in the fuel react with oxygen in an exothermic reaction fuel+O2-to co2 plus h20

In complete combustion of a hydrocarbon fuel :

carbon dioxide and water are produced the maximum amount of energy is given out

In a Bunsen burner,complete combustion occurs when

the air hole is fully open.

complete combustion general word equation

hydrocarbon + oxygen → carbon dioxide + water

Incomplete combustion happens when the supply of air or oxygen is -----. ------- is still produced, but -------------- and ---------- are produced. --------- energy is released than during complete combustion. In a Bunsen burner, incomplete combustion occurs when ---------------------------

poor water carbon monoxide carbon less the air hole is closed.

Cracking is a reaction in which

larger saturated hydrocarbon molecules are broken down into smaller, more useful hydrocarbon molecules, some of which are unsaturated:

explain the starting reactants and products of cracking

the original starting hydrocarbons are alkanes the products of cracking include alkanes and alkenes , members of a different homologous series

Various methods can be used for cracking,;

eg catalytic cracking and steam cracking:

Catalytic cracking :

uses a temperature of approximately 550°C and a catalyst known as a zeolite which contains aluminium oxide and silicon oxide

Steam cracking

uses a higher temperature of over 800°C and no catalyst

Reasons for cracking Cracking is important for two main reasons:

1. It helps to match the supply of fractions with the demand for them. 2. It produces alkenes, which are useful as feedstock for the petrochemical industry.

The supply is------------------------------------------------------------------ The demand---------------------------------------------------------------------------Very often of crude oil produces more of the--------------- than can be -----, and less of the -----------------than ------------------------------------

how much of a fraction an oil refinery produces. is how much of a fraction customers want to buy. larger hydrocarbons sold smaller hydrocarbons customers want

How does cracking solve the supply and demand problem

Smaller hydrocarbons are more useful as fuels than larger hydrocarbons. Since cracking converts larger hydrocarbons into smaller hydrocarbons, the supply of fuels is improved. This helps to match supply with demand.

Alkanes and alkenes both form -------------------------- of hydrocarbons, but:

homologous series alkanes are saturated their carbon atoms are only joined by C-C single bonds alkenes are unsaturated they contain at least one C=C double bond

alkanes are saturated their carbon atoms are only joined by C-C single bonds alkenes are unsaturated they contain at least one C=C double bond as a result :

As a result, alkenes are more reactive than alkanes. Alkenes can take part in reactions that alkanes cannot. For example, ethene molecules can react together to form poly(ethene), a polymer because alkenes have a double bond which can break

What is the order for complicated balancing equation questions?

MINHO: This is the order of how to balance equations that are complicated M Metals I Polyatomic Ions N Non Metals H Hydrogen O Oxygen

Combustion of alkenes

- burn with a smokier, yellow (luminous) flame than alkanes - Incomplete combustion is more common with alkenes -less energy efficient than alkanes, so do not make such good fuels - do burn completely too

viscosity

(how easily it flows) increases as the chain length increases-flows less easily

Flammability

(how easily it burns) increases as chain length increases

Test for unsaturation explained

if there is as an alkene there will be a positive test for unsaturation because the water will turn from colourless to orange showing that the unsaturated alkene has bonded with the bromine if there is an alkane there will be a negative test for unsaturation because the water will remain colourless because the alkane is already saturated and thus cannot bond with the bromine water

Thermal decomposition

is a chemical reaction that happens when a compound breaks down when heated.

Thermal decomposition reactions usually occur at-----------------this ------ breaks the -------- down into ---------------------------

very high temperatures , heat, substance, two or more substances

thermal decomposition is an example of an --------- reaction this means that it ------------------------- so -------------- must constantly be supplied ----------- reaction -------

endothermic gains energy from the surroundings thermal energy to keep going

naming thing for polymerisation

put the word poly in front of the monomers namr

testing for alkenes

bromine turns from orange- to colourless

why is carbon monoxide bad

toxic gas that binds to red blood cells oxygen cant reach around the body

viscosity and flammabiity

first increases as chain length increases second decreases