Organic Chemistry Nov 2018 Flashcards
What is crude oil?
Crude oil is a fossil fuel that is found underground in rocks. It has formed over millions of years by sea creatures (mainly plankton) being squashed and buried in mud.
What are alkanes?
Alkanes are a homologous series of saturated hydrocarbons with a general formula of CnH2n+2.
What is a hydrocarbon?
A molecule made up of only hydrogen and carbon.
What does it mean by saturated?
It is a molecule that contains only single covalent bonds.
What is a homologous series?
A family of compounds with the same general formula, the same functional group and similar chemical properties.
What is the displayed formula?
A drawing of a molecule showing all atoms and bonds.
What is a fraction?
A mixture of molecules with similar boiling points.
What is fractional distillation?
A method used to separate miscible liquids with different boiling points.
What is a fractionating column?
The apparatus used is the process of fractional distillation.
What are the 4 alkanes you need to know?
Methane, Ethane, Propane, Butane
Meth = 1 carbon, Eth = 2 carbons, Prop = 3 Carbons, But = 4 carbons
How does fractional distillation work?
Crude oil enters a fractionating column at the bottom. It is then heated. The alkanes found in crude oil are all different lengths which means they have different boiling points. Due to the fractionating column decreasing in temperature the higher it goes, smaller alkanes with lower boiling points condense further up with larger alkanes condensing lower down and some not boiling at all and forming bitumen at the bottom.
What are the properties of alkanes?
Long alkanes - High boiling points, Viscous, Hard to
ignite & Burn with a smoky flame.
Short alkanes - Low boiling points, Runny, Easy to ignite
& Burn with a clean flame.
What is complete combustion? Incomplete combustion?
Complete combustion - When a substance burn with a
good supply of oxygen.
Incomplete combustion - When a substance burns with
a poor supply of oxygen.
What is cracking?
The thermal decomposition of long alkanes into shorter alkanes and alkenes.
What is an alkene?
A homologous series of unsaturated hydrocarbons with the general formula CnH2n.
What does it mean by unsaturated?
A molecule that contains one or more double covalent bonds.
What are the 4 alkenes you need to know?
Ethene, Propene, Butene, Pentene
Eth = 2 carbons, Prop = 3 Carbons, But = 4 carbons, Pent = 5 carbons
What is the functional group in alkenes?
C = C (= is double covalent bond)
Functional group - Atom or group of atoms responsible
for most of the chemical reactions of
a compound.
What is an addition reaction?
A reaction in which atoms bond to the atoms in a C = C double bond to form a saturated molecule.
What is hydrogenation? Hydration?
Hydrogenation - Addition of hydrogen
Hydration - Addition of water
Why are alkenes very valuable?
Alkenes can be used to polymers or they can be used as a starting material for many other chemicals.
Why do you not normally burn alkanes in oxygen?
They burn with a smoky flame due to incomplete combustion.
