Seneca 7.2 Flashcards
What is the formula for alkenes
A homologous series is a series of compounds with the same general formula.
Alkenes are a homologous series with the general formula CnH2n.
What are the properties of alkenes
. Unsaturated
. More reactive than alkenes
. Contain a double bond
Why are alkenes unsaturated
they contain a double bond between two of their carbon atoms (C=C).
This means that an alkane and alkene with the same length of carbon chain will have different numbers of hydrogen atoms - the alkane will have two more hydrogen atoms.
What are alkenes
Alkenes are hydrocarbons with the functional group C=C. This means that alkenes have a carbon-carbon double
bond.
Why are alkenes more reactive than alkanes
The presence of the C=C functional group means that alkenes have greater reactivity than alkanes.
What are the four shortest alkenes in ascending order
.Ethene C2H4
.Propene C3H6
.Butene C4H8
.Pentene C5H10
Addition reaction
When a double bond opens up allowing new atoms to bond.
Functional group
A collection of atoms that impact the reactions of an organic compound.
Alkenes and oxygen
Alkenes can be involved in combustion reactions with oxygen. The outcome of these reactions is similar to when other hydrocarbons react with oxygen
Ethene (C2H4) + oxygen (O2) → carbon monoxide (CO) + carbon (C) + water (H2O)
Because their combustion is incomplete, they burn with smoky flames.
Alkenes and halogens
Alkenes, unlike alkanes, will react if mixed with bromine water and shaken. This causes the solution to change color from orange-brown to colorless.
This is an effective test for distinguishing between alkenes and alkanes
Alkenes and hydrogen
When a nickel catalyst is present, alkanes can be formed by combining hydrogen with an alkene
Adding hydrogen atoms across a carbon-carbon double bond is called hydrogenation.
Ethene (C2H4) + hydrogen (H2) → ethane (C2H6)
Alkenes and water
When a phosphoric acid catalyst is present, alcohols can be formed by reacting alkenes with steam
Ethene (C2H4) + steam (H2O) → ethanol (C2H5OH)
What happens during an alkene addition reaction
A carbon - carbon double bond opens up
What is the functional group of alkenes
C=C
What do you need for alkenes to react with water
. The water to be in a gaseous state
. A phosphoric acid catalyst
What is the general series (homologous series) of alcohols
The homologous series of alcohols have the general formula
CnH2n+1 OH.
What is the functional group of alcohols
The functional group of alcohols is a hydroxyl group (-OH).
What are the 4 smallest alcohols in ascending size order
.Methanol CH3OH
.Ethanol CH3CH2OH
.Propanol CH3CH2CH2OH
.Butanol CH3CH2CH2CH2OH
What are the properties of alcohol
. Hydroxyl group
. General formula is CnH2n+1 OH.
What happens when alcohols and sodium react together
When alcohols and sodium react together, hydrogen is produced.
What happens when alcohols and water react together
When alcohols are added to water, they dissolve to give neutral solutions.
What happens when alcohols and oxidizing agents react together
When alcohols react with a strong oxidizing agent, a carboxylic acid is produced.
What happens when alcohols and air (and heat) react together
When alcohols react with air (and heat), carbon dioxide and water are produced.
What is fermentation
Fermentation is a common method for producing ethanol
What is the process of fermentation
The process of fermentation involves adding yeast to a sugar solution. The resulting reaction gives:
An aqueous solution of ethanol.
Carbon dioxide.
What are the conditions for fermentation
The ideal conditions for the fermentation of sugar using yeast are:
A temperature of 37°C.
A solution that is slightly acidic.
In the absence of oxygen (anaerobic).
What is the general formula for carboxylic acids
The general formula for the homologous series of carboxylic acids is CnH2n+1COOH.
What property do carboxylic acids have
Carboxylic acids only partially ionize (form an ion) in water, meaning they are weak acids.
What is the functional group of carboxylic acids
The functional group of carboxylic acids is a carboxyl group (-COOH).
What are the four smallest carboxylic acids in ascending order
. Methanoic acid HCOOH.
. Ethanoic acid CH3COOH
. Propanoic acid CH3CH2COOH
. Butanoic acid CH3CH2CH2COOH
What happens when a carboxylic acid reacts with carbonates
When carboxylic acids react with carbonates, the products are:
A salt
Carbon dioxide
Water
What happens when carboxylic acids react with water
When carboxylic acids react with water, they dissolve to give solutions with an acidic pH.
What happens when carboxylic acids react with alcohols ( and an acid catalyst)
When carboxylic acids and alcohols react together (using an acid catalyst), an ester and water are produced
What is needed for carboxylic acids to react and produce esters?
Alcohol
Acid catalyst
What is addition polymerization
Addition polymerisation is the joining of short-chain monomers to produce one long-chain polymer.
What are the monomers in addition polymerisation?
Alkenes are the monomers used in addition polymerisation.
This is because the carbon-carbon double bonds in alkenes can open up to allow multiple alkenes to join together.
What are the products of addition polymerization?
In addition polymerisation, the polymer is the only product of the reaction.
This means that the repeating unit has exactly the same atoms as the monomer.
How do we name addition polymers
Naming addition polymers is very simple. Start with ‘poly’ and then put brackets around the name of the monomer.
Poly(ethane)
When ethene monomers undergo addition polymerisation, poly(ethene) is the product.
Poly(propene)
When propene monomers undergo addition polymerisation, poly(propene) is the product.
Why are alkenes used in addition polymerization
This is because the carbon-carbon double bonds in alkenes can open up to allow multiple alkenes to join together.
What is condensation polymerisation
Condensation polymerization describes the joining together of monomers with 2 functional groups to produce larger polymers, as well as small molecule by-products
How is the simplest type of condensation polymer produced
The simplest type of condensation polymer is produced by combining 2 monomers that each have 2 identical functional groups
What are the products of condensation polymerization
. A small by - product
. A large polymer
What are the functional groups of amino acids?
Amine group (-NH2)
Carboxyl group (-COOH)
Polymerization of amino acids
Amino acids can be combined by condensation polymerization. The products of this reaction are a polypeptide and water.
What are the bonds that form to connect the amine and carboxyl groups of amino acids in polypeptides
Peptide links
What does DNA stand for
deoxyribonucleic acid
What is the role of DNA
DNA encodes (produces) the genetic instructions used in the development, functioning and reproduction of living organisms and viruses.
What is the shape of DNA
Most DNA molecules are made up of 2 polymer chains arranged in the form of a double helix.
What are the main components of DNA
The polymers are made from monomers known as nucleotides. Each nucleotide contains 1 of the following 4 nitrogenous bases
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
What are other naturally occurring polymers
. Proteins
. Starch and cellulose
