Chapter 12 - organic chemistry Flashcards
Why can carbon form so many compounds ?
- a carbon atom can form bonds with other carbon atoms to make chains and rings
- a carbon atom can form a single or double bond with another carbon atom
- a carbon atom can bond with other atoms e.g hydrogen , oxygen and chlorine
What are the features of a homologous series ?
- have the same general formula
- show similar chemical properties
- show gradation in their physical properties
- differ by a ‘CH2’ unit
What is the alkanes general formula ?
CnH2n+2
What is the colour and state of all the alkanes ?
they are all colourless gases
What is a hydrocarbon ?
A hydrocarbon is a molecule consisting of carbon and hydrogen atoms only
What does saturated mean ?
Saturated means that all the carbon-carbon bonds are single
What is the molecular formula for methane and propane ?
methane : CH4
propane: C3H8
What is a functional group ?
A functional group is a reactive group in a molecule
What are the alkanes functional group ?
The alkanes don’t have a functional group
What is the definition of combustion ?
combustion is the reaction of fuels with oxygen, forming oxides and releasing heat energy
What are the products when alkanes undergo complete combustion ?
water + carbon dioxide (energy is released)
orange flame observed
What are the products when alkanes undergo incomplete combustion ?
carbon monoxide + water ( energy released)
What is the formula for carbon monoxide ?
CO
What does carbon monoxide do to the body ?
Its a toxic gas that prevents the blood from carrying haemoglobin. Headaches, dizziness, nausea
How is soot formed and what problems does it cause?
Formed by incomplete combustion of fuels and the carbon particles pollute the air and cause lung damage
How is sulfur dioxide formed and what problems does it cause
Many fuels contain sulfur impurities which burn and produce acidic sulfur dioxide. It can damage buildings, damage vegetation and kill fish in lakes and rivers
What is the general formula of the alkenes
CnH2n
What is the functional group of the alkenes ?
The carbon to carbon double bond (C=C)
Due to this the alkenes are more reactive than the alkanes
What is the state and colour of all the alkenes at room temperature ?
all alkenes are a colourless gas at room temperature
What are the molecular formulas for all the alkenes?
ethene : C2H4
propene : C3H6
but-1-ene : C4H8
but-2-ene : C4H8
What are the products when the alkenes undergo in/complete combustion ?
incomplete : carbon monoxide + water
complete : carbon dioxide + water
What does the term unsaturated mean ?
Unsaturated means that the molecule contains one or more carbon-carbon double bonds.
What is an addition reaction ?
An addition reaction is one in which two molecules react to form one product
What is the test for the alkanes and alkenes ?
Shake the alkene or alkane with bromine water and if its and alkane it will stay orange and if it turns colourless it means it is an alkene.
What happens when an addition reaction occurs with hydrogen and an alkene ?
The hydrogen bonds across the C=C and it turns into an alkane
What are the conditions of the addition reaction between and alkene and hydrogen ?
150*C
catalyst of nickel
What is the name given when an addition reaction occurs with hydrogen and an alkene ?
hydrogenation
give one use of hydrogenation
Making unsaturated fats into saturated fats.
When alkenes react with steam what do they produce ?
alcohol
What is the process called when alkenes react with steam ?
hydration
What are the conditions for alkenes react with steam ?
high temperature and a catalyst
What is the definition of a polymer ?
A polymer is a long chain molecule made from joining small molecules together
What is the definition of a monomer ?
A monomer is a small molecule that combines with other monomers to make a polymer
What is the definition of an addition polymerisation ?
Addition polymerisation is the process of joining monomer molecules together to form a long chain molecule
What is the definition of non-biodegradable material ?
A non-biodegradable material is one which is not decomposed by natural bacteria in the environment
What are the (dis)advantages of the various methods of disposal of non-biodegradable materials ?
You know them
What is the general formula of alcohols ?
CnH2n+1OH
What is the colour and sate of all the alcohols at room temperature ?
they are all colourless liquids
What is the molecular formula for all of the alcohols ?
methanol : CH3OH
ethanol: C2H5OH
propanol : C3H7OH
What is observed when alcohol is burned in a plentiful supply of oxygen ?
A clean (non smoky) blue flame with an orange tip
What is the word equation when ethanol reacts with oxygen ?
ethanol + oxygen —–> carbon dioxide + water
What is the word equation when ethanol reacts with limited oxygen ?
ethanol + limited oxygen —-> carbon monoxide + water
What alcohol can not form a carboxylic acid ?
prop-2-anol
Name the three carboxylic acids formed when the alcohols get oxidised
ethanoic acid
methanoic acid
propanoic acid
Draw out the structure of methanoic acid
PLLLEEEAAASSE
What does acidified potassium dichromate solution do to alcohols ?
acidified potassium dichromate solution is an oxidising agent which oxidises some alcohols, on warming.
What are the observations and what are the conditions when acidified potassium dichromate solution oxidises an alcohol ?
the acidified potassium dichromate solution changes from orange to green
warm in a water bath
What is the definition of fermentation ?
Fermentation is the breakdown of sugars to produce ethanol and carbon dioxide
What are the conditions for fermentation ?
- the sugars are dissolved in the solution
- in the presence of yeast
- at a warm temperature (not above 37*C)
- in the absence in air
What is the colour and state of all the carboxylic acids at room temperature ?
all are colourless liquids
What is the molecular formula of all the carboxylic acids ?
methanoic acid : HCOOH
ethanoic acid : CH3COOH
propanoic acid : C2H5COOH
butanoic acid : C3H7COOH
What are the names of all the carboxylic acids and their symbols ?
methanoate: HCOO-
ethanoate: CH3COO-
propanoate: C2H5COO-
butanoate: C3H7COO-
How do carboxylic acids burn ?
they do not burn easily
What is crude oil ?
Crude oil is a mixture containing mainly alkane hydrocarbons
What are petrochemicals ?
petrochemicals are chemicals made from petroleum and natural gas
What is the method for separating hydrocarbons ?
- the crude oil is heated and vaporised
- the vaporised crude oil enters a fractioning tower which is hotter at the bottom
- the hydrocarbons cool as they rise up the tower and condense at different heights because they have different boiling points
- hydrocarbons with large molecules are collected at the bottom while those with small molecules are collected at the top
Name 5 uses for the fractions of crude oil :
- petrol used for fuel for cars
- kerosene as fuel for aircraft
- diesel as fuel for cars and trains
- fuel oils used for fuel for ships
- bitumen used for surfacing roads
What is the definition of cracking ?
Cracking is the breakdown of larger saturated hydrocarbons into smaller more useful ones, some of which are unsaturated.
Why is cracking used?
Shorter chain alkanes are in very high demand as fuels
How is cracking carried out ?
Cracking is carried out by heating. It is thermal decomposition reaction because the alkanes are broken down into smaller molecules using heat
