YEAR 10 – Topic 10 – Oils, Alkanes, Alkenes and Alcohols Flashcards
What is a hydrocarbon?
A hydrocarbon is a molecule or a compound made from hydrogen and carbon ONLY.
What is an alkane?
An alkane is a saturated hydrocarbon compound, as it only has carbon - carbon single bonds. It can undergo substitution reactions. General formula: CnH2n+2
What is an alkene?
An alkene is an unsaturated hydrocarbon compound with a carbon - carbon double bond. They can undergo addition reactions and are a product of cracking. General formula: CnH2n
What is an alcohol?
Alcohols have a general formula of CnH2n+1OH. The functional group is OH. They can be oxidised to make carboxylic acids.
What is the general formula of an alkane?
CnH2n+2
What is the general formula of an alcohol?
C n H 2n+1 OH
What is the general formula of an alkene?
CnH2n
What is the order for the prefixes we use for alkanes and alkenes?
Meth- Eth- Prop- But- Pent- Hex- etc...
What is a functional group?
A functional group is an atom or a group of atoms that determines the main chemical properties of an organic compound. Eg. Alcohols = OH
What is an isomer?
An isomers are compounds with same molecular formula but a different displayed formula. (Can’t be flipped) this is easy to practice rather than flashcards… Ok
What is a molecular formula?
A chemical formula for a compound that gives the total number of atoms of every element in the molecule. Eg water = H2O
What is a structural formula?
A chemical formula for a compound which shows the arrangement of atoms in the molecule of the compound. Eg: CH3CH2CH3
What is the displayed formula?
The displayed formula is a structural formula that is drawn out. It shows how the atoms could be arranged in a 3D space.
What is an empirical formula?
A formula giving the proportions of elements present in a compound but not the actual numbers or arrangement of atoms. Eg: octane = C4H9
It is the simplest form of a compound
What is crude oil?
Crude oil is a fossil fuel and is made up of hundreds of different compounds, of which mainly hydrocarbons. It can be separated with fractional distillation.
What is fractional distillation?
Fractional distillation is a way of separating a mixture of liquids because of their different boiling points. An example is separating crude oil into it’s fractions.
Are the fractions pure substances or mixtures? Why?
They are a mixture as they boil over a range of temperatures (not like 100° exactly).
Properties of small hydrocarbons:
Small hydrocarbons:
- higher demand
- low boiling points (high up the fractioning column thingy)
- high flammability
- burns with a clean flame
- low viscosity (runny and easy to pour)
Properties of large hydrocarbons:
Properties of large hydrocarbons:
- lower demand
- high boiling points (lower in the fractioning column thingy)
- low flammability
- smoky flame
- light in colour
- high viscosity (thick and not easy to pour)
What is the order (from top to bottom) of the fuels produced in fractional distillation of crude oil?
Fuel gases (<40°c) Gasoline (petrol) (40-90°c) Naphtha (not sure what this is amz) (90-160°c) Kerosene (jet fuel) (160-250°c) Diesel (250-350°c) Residue/ Bitumen (>350°c)
What is a homologous series?
A homologous series is a series of compounds that:
- have the same functional group, so they have similar chemical properties
- show a trend (gradation) in physical properties
- can be described using the same general formula
- differ from the next by a -CH2- unit alkanes form the simplest of this series.
What is the difference between a saturated and an unsaturated hydrocarbon?
Saturated
– Only single C-C bonds
– Called alkanes
– General formula of CnH2n+2
Unsaturated
– Have double C=C bond/s (sometimes triple bonds)
– Called alkenes
– General formula of CnH2n
Short chain hydrocarbons have a _____ boiling point.
(Low/High)
What does this mean?
Low
They boil/ evaporate at lower temps.
Long chain hydrocarbons have a _____ boiling point.
(Low/High)
What does this mean?
High
They boil/ evaporate at higher temps.
Short chain hydrocarbons have a _____ viscosity.
(Low/High)
What does this mean?
Low
It means that they are more runny/pourable!!!
Long chain hydrocarbons have a _____ viscosity.
(Low/High)
What does this mean?
High
They are less runny/not pourable!!!
Short chain hydrocarbons have a _____ flammability.
(Low/High)
What does this mean?
High
They catch on fire more easily.
Long chain hydrocarbons have a _____ flammability.
(Low/High)
What does this mean?
Low
They don’t catch on fire easily.
Short chain hydrocarbons have a _____ volatility.
(Low/High)
What does this mean?
High
They turn into gases more easily.