Chemistry Paper 2 Flashcards
chem: what is a monomer
a molecule that can bond to other monomers to make polymers
chem: what type of atom are monomers often
they are often alkenes (methane)
chem: in polymers what are the intermolecular forces of attraction
strong
Chem: why do polymers have higher melting and boiling points that smaller molecules
Because they have stronger intermolecular forces
Chem: why do polymers have higher melting and boiling points that smaller molecules
Because they have stronger intermolecular forces
chem: in polymers are covalent bonds weak or strong
they are extremily strong
Chem: what are the 2 principles of Le Chateliers Principle
- If the conditions change then the posision of equalibrium changes
- If the conditions change then the system responds to counteract the change.
Chem: what does equilibrium mean
The forward and reverse reactions occur at the same rate in a closed system
Chem: what does equilibrium mean
The forward and reverse reactions occur at the same rate in a closed system
Chem: for equilibrium, does the amount of products and reactants have to be equal
No the only must remain the same, individually
Chem: what is dynamic equilibrium
It is equilibrium where both froward and backward reactions are still happening, the rates of forward and reverse reactions are the same, concentrations of chemicals do not change and it only happens in a closed system
Chem: what is collision theory
A theory that for a reaction to occurr particles must collide with enough energy
Chem: what explains why reactions happen at different rates
Collision theory
Chem: what are alkanes
They all end in ‘ane’
They are hydrocarbons
There formula is CnH2n+2
Chem: what are hydrocarbons
They are molecules made up of hydrocarbons
Chem: what is crude oil found in
Rocks
Chem: what are the properties of hydrocarbons
- high boiling points
- higher viscosity
- less flammable
Chem: what happens to the position of equilibrium when you increase pressure
Shift in the direction of the reaction the produces the freshest gas molecules
Chem: what happens to the position of equilibrium when you decrease pressure
Shifts toward the reaction the produces the most gas
Chem: what happens to the position of equilibrium when you increase concentration of the reactant
Shifts the equilibrium position toward the products
Chem: what happens to the position of equilibrium when you decrease concentration of the reactants
Shifts towards the reactants
Chem: what happens to the position of equilibrium when you increase temp
Shifts to endothermic
Chem: what happens to the position of equilibrium when you decrease temp
Shifts to the Exothermic
Chem: what is crude oil made of
It is a mixture of lots of compounds, many hydrocarbons
Chem: what is fractional distillation in relation to crude oils
It is the process of separating crude oil into groups of hydrocarbons with similar numbers of carbon atoms, these groups of hydrocarbons are called fractions
Chem: what are hydrocarbons with lots of carbon atoms calles
Long chain hydrocarbons
Chem: what are hydrocarbons with little amounts of carbon atoms called
Short chain hydrocarbons
Chem: what do all organic compounds contain
Carbon
Chem: what is the equation for burning hydrocarbons when there is plenty of oxygen
- energy is released
- carbon dioxide and water is produced
Chem: what happens when there is not enough oxygen when burning hydrocarbons
Carbon monoxide is produced
Chem: what are the properties of heavy fractions of crude oil
- don’t ignite easily
- high boiling points
- low volatility
Chem: what is cracking
It is the process of breaking down long chain hydrocarbons into short chain hydrocarbons and alkenes that are more useful, it is thermal decomposition
Chem: what is catalytic cracking
Vaporised heavy hydrocarbons are passed over the top of a heated catalyst, this produces alkanes and alkenes, e.g. hexane -> butane + ethane, it is preferred in industry as it produces more useful petrol at lower tamps and pressures.
Chem: what is steam cracking
Vaporised heavy hydrocarbons are combined with steam at high temperatures, it produces alkanes and alkanes.
Chem: what are some uses of hydrocarbons
- being starting materials for chemicals like ethanol
- being combined to make polymers
Chem: how does fractional distillation of crude oil happen
- crude oil is vaporised and enters a fractioning column
- vapours condense at different points and are collected as fractions at these points
Chem: what is diesel oil used in
Cars and trains
Chem: what is kerosine used for
Jet fuel
Chem: what is heavy fuel oil used for
Fuel on ships and in power stations
Chem: what are liquified petroleum gasses used for
Fuels
Chem: what is a homologous series
It is a series of compounds that can be represented by a formula
Chem: why do alkanes have higher melting and boiling points the larger they are
They have more covalent bonds so there are more intermolecular forces to overcome to changed the state and so more energy is required
What are alkenes
They are unsaturated as they have a double carbon bond
Chem: what is a fractioning column
It a piece of equipment used in the fractional distillation of crude oils
Chem: what is the general formula of alkenes
Chem: are alkenes reactive
Their double carbon bond means they are more reactive that the alkanes
Chem: what are the 4 smallest alkenes, in order for smallest to largest
Ethene (2 carbon), propene, butene, pentene(5 carbon)
Chem: how many carbon atoms does pentene have
5
Chem: what is a functional group
A collection of atoms in an organic molecule that affects its reaction e.g. the functional group I alkenes is the carbon carbon double bond
Chem: what is a typical reaction for an alkene
Addition