Organic Chemistry Flashcards
Organic
Compounds that are based on C, with other elements such as H, O, N
Homologous series
A group of chemicals with the same general formula, a pattern of physical properties, and similar chemical properties.
Hydrocarbons
Compounds consisting of only C+H atoms.
They are saturated because they onely contain single bonds.
Alkanes
Hydrocarbons with only single bonds
What is the suffix when organic chemicals?
Homologous series ending
e.g. In alkanes it would be -ane
What is the genergal formula for alkanes?
What bonding do alkanes have?
Covalent bonds
What happens to the mpt/bpt of alkanes as the molecules get bigger?
Mpt/bpt increase due to more IMFs.
Viscosity
Resistance to liquid flow (thicker or thinner liquid e.g. water vs. honey).
What happens to the viscosity of alkanes as the molecules get bigger?
Increases due to more IMFs and larger molecules inter-twine.
What happens to the valatility of alkane as the molecules get bigger?
Decreases due to to increasing bpt.
Valatility
Ease of turning into a gas.
What is empirical formula?
The lowest ratio of elements within a compound.
What is the molecular formula?
The number of atoms of each element in a molecule.
What is the structural formula?
The atoms connected to each C atom, listed in order.
What is the displayed formula?
The exact bonds connecting each atom in a molecule (simplified version of covalent bonding dot and cross diagram)
What is the bonding diagram?
The dot and cross diagram.
Isomers
Compounds with the same molecular formula but a different arrangement of atoms (diff. structural formula).
What does the root in naming chemicals represent?
The longest line of C atome you can go through without lifting your pen.
What is the prefix
When naming organic chemicals
Any additional atoms not yet included (that are connect)
NOTE: if there are 2 extra C atoms that do not connect to eachother than they will be considered dimeth… because it is 2 of 1.
Saturated
in organic chemistry
Hydrocarbon molecules in which all carbon-carbon bonds are single covalent bonds.
How reactvive are alkanes?
Alkanes are generally unreactive due to only containing strong single covalent bonds (saturates).
What is required to make alkanes react?
Energy in the form of:
* Light
* Heat
* Electricity
What types of reactions do alkanes undergo?
- Substitution
- Combustion
- Decomposition
How does substitution (halogens) work with alkanes?
One of the H atoms swaps with one of the halogen atom.
NOTE: keep in mind that several different types of haloalkanes could be made because the halogen swaps with a different positioned H atom.
What happens when there are multiple prefixes?
Arranged alphabetically
What happens when there are multiple numbers?
They are arranged numerically.
alkane + halogen =u.v. light=>
haloalkane + hydrogenhalide
What is the equation for a complete combustion reaction (alkane)?
alkane + oxygen => carbondioxide + water
What are the incomplete combustion equations?
- alkane + oxygen => carbonmonoxide + water
- alkane + oxygen => carbon + water
Write an equation which produces carbonmonoxide
alkane + oxygen => carbonmonoxide + water
Why is carbonmonoxide dangerous?
It is toxic, it replaces the oxygen in haemoglobin
What can you do to protect yourself from carbonmonoxide?
Have efficient ventilation to avoid incomplete combustion
Why is carbon dangerous?
It damages lungs and machinery
Write an equation which produces carbon
alkane + oxygen => carbon + water
Why does incomplete combustion occure?
It is a product of the incomplete combustion of hydrogen.
Why does incomplete combustion sometimes produce carbon (what does this do to the flame)?
Because the particles of carbon have not even reacted to produce carbon monoxide. it is these fine particles of carbon that can glow yellow in the heat of flame.
What is another word for decomposition (of alkanes)?
Cracking
Why would you want to decompose an alkane?
Because the larger alkane molecules are less flamable.
What is the equation for cracking?
Large alkane => smaller alkane + alkene
What is the smaller alkane used for in cracking?
fuel
What is alkene used for?
Making plastic
What reactions can alkanes undergo?
- substitution
- combustion
- decomposition
What is needed to do decomposition?
- Heat (to 300 clecius)
- Catalyst of Al2O or SiO2
What is the ending in alkenes?
-ene
How do you seperate the isomers created in substitution?
Fractional distillation.
Alkene
hydrocarbons with at least one (only 1 for IGCSE) carbon double bond.
General formula for alkenes
CnH2n
In alkenes, where does the number to indicate where the double bond is go?
after the root, before the suffix.
Are alkenes saturated?
No, alkenes are unsaturated because they contain a double bond.
How reactive are alkenes and why?
Alkenes are more reactive than alkanes because they are unsaturated (half of double bonds can break easily).
What 2 reactions can alkenes undergo?
- Adddition
- Polymerisation
- they can also undergo combustion (but it would be a waste of recourses)
What occures during addition reactions?
an alkene and a halogen react. The double bond in the alkene breaks, this creates 2 spaces for 2 more bond to be formed. The halogen bonds with the carbon. The product is an -ane because it has only single bonds.
What are the differences of addition compared to substitution?
i) only one product with addition of halogens
ii) no additional energy required for addition
iii) addition forms a dihalo product, substitution forms monohalo product.
iv) substitutionis only possible in alkanes.
What are 3 chemicals addition can occur with?
- Halogens
- Hydrogen halides
- Water
How is addition with hydrogen halides named?
The 2 spaces that are opened are filled with, one with an H atom and the other with a halogen atom. We write the position of the halogen atom in front of the whole name + its position
alkene + water =>
alcohol
ol = suffix for alcohol
(OH has joined in place of one of the bonds and other H taken other place)
We number the OH (goes after root before suffix)
Alkanes / alkenes test
Polymerisation
alkenes can undergo polymerisation to form plastics (polymers). This occures through addition.
What is a repeating unit?
How we display polymers
What are the physical properties of polymers?
- Low mpt (covalent, discrete), weak IMFs etc…
=> but higher than monomers due to large molecules - do not conduct electricity
- insoluble in water but soluble in oils
What are the chemical properties of polymers?
Unreactive (saturated)
same as alkanes
What are the enviornmental problems with polymers?
- If they are combusted than thst releases CO2 (global warming) and non-metal oxide which is an acid (acid rain)
- They are disposed of in landfills (non-biodegradable)
- Plastic escpaes into lakes/rivers (oceans)
Carboxylic acids
Organic chemicals that also contain oxygen. Acids which contain the group -COOH
What is the suffix of carboxylic acid?
-oic acid
How are carboxylic acids formed?
By oxidising alcohols using an oxidising agent
What oxidising agents can be used to make carboxylic acids?
- K2Cr2O7
- KMnO4
What is the color change of K2Cr2O7 when an alchohol is oxidised?
Cr^6+ (orange) ==> Cr^3+ (green)
What is the color change of KMnO4 when an alchohol is oxidised?
Mn^7+ (purple) ==> Mn^2+ (pink)
What is the strength of carboxylic acids?
They are week acids as the H (from COOH) partially dissociates to release H^+ ions.
What symbol represents oxidising agents?
Square brackt O Square bracket
What does an alcohol and a oxidizing agent make?
an aldehyde (a double bonded O and a H on the end)=> caboxylic acid (a double bonded O and a OH (additional O))
General formula:
ethanol ==oxidizing agent=>
apples => vinegar (these are used for food flavoring)
acid + metal =>
salt + hydrogen
acid + base =>
salt + water
acid + metalcarbonate =>
salt + water + carbondioxide
How do carboxylic acids react?
In the same way as inorganic acids
How do carboxylic acids react in the same way as inorganic acids?
During these reactions the H+ from the COOH is comparable to the H+ in HCl. The metal/base etc. switches with the H from the OH.
How do we name the salts produced from carboxylic acids?
The salts produced have the names based on the carboxylic acid, with the suffix -oate.
What types of salts does ethanoic acid form?
ethanoate salts
What are 2 methods of the manufacture of ethanol?
a. direct hydration of ethene
b. fermentation of sugars
Advantages of direct hydration of ethene
- continuous process
- product is pure (no seperation needed)
Disadvantages of direct hydration of ethene
- high energy demand (fossil fuel power stations)
- ethene comes from cracking (and alkanes need to be extracted from crude oils)
- alkanes are non-rewnewable
Describe the direct hydration of ethene
- ethene (double bond) and water make ethanol.
- This process requires a concentrated catalyst
=> H₂SO₄
=> H₃PO₄ - This process requires heat (600°C)
- This reaction makes 100% ethanol
What is 100% ethanol used for?
It is used as a disinfectant/solvent
Advantages of fermentation of sugars
- sugar and fruit provide flavor
- renewable recources
- low energy demand
Disadvantages of fermentation of sugars
- batch process (slow)
- product is a mixture
=> ethanol produced needs to be separated if a higher conc. is desired
Describe the fermentation of sugars
- sugar makes ethanol and carbondioxide
- Reaction requires yeast
- uses sugar (from fruit)
- the max. concentration of the result is 15% because:
=> fruit is not 100% sugar
=> ethanol will kill yeast, stopping the process
=> distillation can produce more concentrated ethanol
What is the general formula for the directy hydration of ethene?
ethene + water ==600°C==H₂SO₄/H₃PO₄==>
ethanol
What are the 2 catalysts which can be used for the direct hydration of ethene?
H₂SO₄
OR
H₃PO₄
What is the general fromula of the fermentation of sugars
sugar =yeast=> ethanol + carbon dioxide
What is the general symbol formula of the fermentation of sugars?
C₆H₁₂O₆ =yeast=> C₂H₅OH + 2CO₂
Ester
A chemical with a specific foprmula:
* any group (R) bonded to…
* a carbon…
=> double bonded to a oxygen
=> bonded to a oxygen…
* bonded to any group (except H)…
* bonded to some hydrogens
What is a esterfication an example of?
esterfication is a example of a condensation reaction.
How do you make an ester?
Using esterfication
What is the general equation fro esterfication?
alcohol + carboxylic acid => ester + water
What happens during esterfication?
The H (attached to the OH) from the alcohol and the OH from the carboxylic acid break apart from the (acid/alcohol) and bond together to make acid. The left over atoms from the acid and the alcohol bond to form an ester.
What are esters used for?
Food flavoring
How do you write a repeating unit of esters (if we use dialcohols and dicarboxylic acid)
—(–The ester without any of the H that were connected to the OH–)–n + (2n - 1) H2O
How fast is esterfication
Very SLOW (days)
How can the rate of esterfication be increased?
- adding a concentrated catalyst (H2SO4)
- increase temp. (~70ºC)
=> low bpt. - constant stirring
=> several of these chemical are imiscible so stiring forces them to come in contact with one another.
What is a catalyst for esterfication (to increase rate)?
Concentrated H2SO4
General formula for carboxylic acids
CₙH₂ₙ ₊₁COOH
Where can ethanoic acid be found?
In vinegar
Where can methanoic acid be found?
In stinging ants and nettel
Amine
-NH2
Prefix of polyamides
amino
How do you form a polyamide?
diamine + carboxylic acid => Polyamide + water
What is a polyamide reaction very similar to?
An esterfication reaction
hat are polymides used for?
- Nylon
=> ropes/threads
=> fishing ropes/leggings
Amiade group/link
HWhat is crude oil?
A mixture of hydrocarbons (alkanes). Which are miscible liquids with diff. boiling pints.
How do we seperate crude oils?
We seperate them into fractions using fractional distillation.
Why do we not seperate each individual substance in crude oils?
Because there are so many diff. chemicals that is would take WAY too long.
Fraction
A group of chemicals with a similar bpt.
What are the steps of the industrial seperateion of oils?
- particles enter column annd most evaporate
- some particles have higher bpt. and remain as liquid, they sink to bottom of column.
- As particles rise through column they cool down and condence.
- the particles condence at diff. heights depending on there bpt.
=> the higher bpt, the sooner they condence. - fractions are collected as liquids
Why are oil plants dangerous?
Because, the oils are seperated at a high pressure and high temp (300 degrees celcius) and alkanesare higly flammeble. This is prone to explode.
What fractions are in higher demand?
Lighter substances (smaller molecules) because they are more flammable.
State the fractions of the seperation of crude oils (in order)
- Natural gas/refinery gas
- Petrol/gasoline
- Naptha
- Paraffin/kerosene
- Diessel
- Fuel oil
- Lubricating oil
- Bitumen
Use of bitumen
Road surfacing
What is an acranym for the order of the fractions of crude oils?
Never Pass Nasty Pests During Fall Lunch Break
OR
Never Grow Natural Kale Directly From Lakes and Burrows
Uses of lubricating oil
Lubrication
Uses of fuel oil
fuel in boats/ships
Uses of diesel
fuel in trucks/lorries
Uses of paraffin/kerosene
fuel in airplanes
Uses of naptha
chemical feedstock
Uses of petrol/gasoline
fuel for cars
