3 - Organic Chemistry Flashcards
What are hydrocarbons?
Chains of carbon and hydrogen atoms only
What is an alkane?
Saturated hydrocarbons (only one carbon - carbon bond)
CnH2n+2
Methane, ethane, propane, butane, pentane
What does saturated mean?
That no more atoms can join onto the carbon atoms as all their bonds are already used
What is a homologous series?
A group of compounds:
- That can all be represented by the same general formula
- Similar chemical properties
- Gradation in physical properties
- Families of organic compounds
What is a homologous series?
A group of compounds:
- That can all be represented by the same general formula
- Similar chemical properties
- Gradation in physical properties
- Families of organic compounds
What is the equation for complete combustion?
alkane + oxygen –> carbon dioxide + water (+ energy)
What is the equation for incomplete combustion?
alkane + oxygen –> carbon + carbon monoxide + carbon dioxide + water (+energy)
What happens when a halogen reacts with an alkane?
- Must be in the presence of UV light
- Makes a haloalkane
- Substitution reaction
What is an alkene?
- Hydrocarbons with a double bond between the carbon atoms
- Unsaturated because they can make more bonds (double bone opens up)
- CnH2n
What is an isomer? Give an example
- Two molecules that have identical molecular formulas but different structures
- Butene
What happens when a halogen reacts with an alkene?
- Makes haloalkanes (double bond opens up)
- Bromine + ethane –> dibromoethane
- Addition reaction
How can you test for alkenes?
- Shake an alkene in orange bromine water
- Turns colourless because the bromine molecules react with the alkene to make a dibromoalkane
How can you test for alkenes?
- Shake an alkene in orange bromine water
- Turns colourless because the bromine molecules react with the alkene to make a dibromoalkane
How can you make ethanol?
- Ethene (from crude oil) reacts with steam to make ethanol
- Temperature = 570*C
- Pressure = 60 - 70 atmospheres
- Catalyst = phosphoric acid
- Cheap and not much is wasted
- It will become expensive as crude oil is non-renewable
How can you make ethanol by fermentation?
- Raw material = sugar (e.g. glucose)
- Converted into ethanol using yeast
- Temperature = 30*C
- All renewable resources
- Not very concentrated so needs to be distilled to increase strength
- Needs to be purified