Chemistry - Chains, Energy and Resources - F322 - Alcohols, Halogenoalkanes and Analysis (2) Flashcards
What are the two methods by which ethanol can be made?
Ethanol can be made by either the hydration of ethene or the fermentation of sugars.
What conditions are required for the hydration of ethene?
The hydration of ethene occurs at 300oC and 60 atm in the presence of a phosphoric acid catalyst.
In the hydration of ethene, what percentage of ethene is converted to ethanol?
5% of the ethene is converted to ethanol.
What enzyme catalyses the fermentation of sugars to produce ethanol?
Zymase
What are the strongest type of intermolecular forces?
Hydrogen bonds are the strongest type of intermolecular forces.
What makes alcohols less volatile than alkanes of a similar molecular mass?
The hydrogen bonds make alcohols less volatile than alkanes of a similar molecular mass.
Define volatiliy.
Volatility is the ease with which a liquid turns to a gas. Volatility increases as boiling point decreases.
Solubility of alcohols decreases as what increases?
Solubility decreases as chain length increases.
What is a primary alcohol?
In a primary alcohol the -OH group is attached to a carbon atom with no alkyl groups or bonded to one alkyl group.
What is a secondary alcohol?
In a secondary alcohol the -OH group is attached to a carbon which is bonded to two alkyl groups.
What is a tertiary alcohol?
In a tertiary alcohol the OH group is attached to a carbon atom bonded to three alkyl groups.
What is a suitable oxidising agent for primary and secondary alcohols?
Acidified dichromate ions are a suitable oxidising agent for primary and secondary alcohols.
What is a primary alcohol oxidised into?
A primary alcohol is oxidised to an aldehyde.
When making a carboxylic acid the reaction mixture is usually heated how?
When making a carboxylic acid the reaction mixture is usually heated under reflux.
Define reflux.
Reflux is the continual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling dry.
What are secondary alcohols oxidised to produce?
Secondary alcohols are oxidised to ketones.
What reacts together to form an ester?
An esterification reaction involves an alcohol reacting with a carboxylic acid.
When naming an ester, in what order is it named?
The alcohol forms the first part of the name, the alkyl part, and the carboxylic acid forms the -oate part of the name.
What is used as the acid catalyst in the formation of esters?
Concentrated sulphuric acid is often used as the acid catalyst in the formation of esters.
What is the general formula of the halogenoalkanes?
CnH2n+1X
What two factors can affect the rate of hydrolysis of halogenoalkanes?
The polarity and the bond enthalpy can affect the rate of hydrolysis of halogenoalkanes.
Which is more important at affecting the rate of hydrolysis of halogenoalkanes, the bond enthalpy or polarity?
Bond enthalpy is more important than bond polarity when it comes to the hydrolysis of halogenoalkanes.
What is the calculation for the percentage yield?
% yield = (actual amount, in mol, of product / theoretical amount, in mol, of product) X 100
Why are yields of 100% rarely obtained?
- the reaction may be in equilibrium
- other side reactions resulting in byproducts
- reactants may not be pure
- some reactant product may be left behind in the apparatus
- separation and purification may result in loss of some of the product
What is the equation for atom economy?
atom economy = (molecular mass of the desired product / sum of the molecular masses of all the products) X 100
What is the atom economy of addition reactions?
Addition reactions have an atom economy of 100%
Where do most organic molecules produce a peak on an infrared spectrum?
Most organic molecules produce a peak at about 3000cm-1 due to absorption by the CH bond.
What is the molecular ion, M+?
The molecular ion, M+ is the positive ion formed in mass spectrometry when a molecule loses an electron.
What is the most common method of ionisation in mass spectrometry?
Electron impact is the most common method of ionisation.
