Fuels and Heats of reaction Flashcards
Hydrocarbon
A compound that contains only carbon and hydrogen
Saturated compound
a compound in which there are only single bonds between the atoms in the molecule
Unsaturated compound
One which contains at least one double or triple bonds netweem the atoms in the molecule
Structural isomers
Compounds with the same molecular formula but different structural formulae
Aliphatic (compound)
An organic compound that consists of straight (open) chains of carbon atoms and closed chain compounds with similar properties
Aromatic (compound)
An organic compound that contains a benzene ring structure in their molecules
Octane Number
Octane number of a fuel is a measure of the tendency of the fuel to resist knocking
Catalytic cracking
The breaking down of long chain hydro-carbon molecules into short chain molecules by heat and catalysts
Auto-ignition
Premature ignition (explosion) of the petrol-air mixture before normal ignition of the mixture by a spark takes place
Alkanes
These compounds are a family of hydrocarbons in which all atoms are linked by single bonds (saturated compounds)
Alkanes - formula
Cₙ H₂ₙ₊₂
Order
Meth Eth Prop But Pent Hex Hept Oct Non Dec
Alkane structual and condensed formulas
on hardback
Alkenes - formula
Cₙ H₂ₙ
Alkenes
- A homologous series of aliphatic hydrocarbons
- Lowest member of the series is ethene (2 carbon atoms)
- Each alkene molecule contains a carbon-carbon double bond
- Unsaturated compounds
Alkenes - methene
No methene due to double bonds
Alkynes endings
ends in -yne
Alkynes
Contain a carbon-carbon triple bond
Highly unsatured
Alkynes formula
Cₙ H₂ₙ₋₂
Ethyne
Name - Ethyne
Formula - C₂ H₂
Structural formula: H - C = C - H
Ethyne is the first of the series as you must have a carbon-carbon triple bond. (You need at least 2 carbons)
Endothermic reaction
Energy + reactants –> products
Activation energy
Activation energy is the maximum point on the reaction graph
Example of exothermic reaction and endothermic reaction
Exothermic reaction: Hydrochloric acid + magnesium
Endothermic reaction: water + ammonium nitrate
Bomb calorimeter
- use
- method
Used to find accurate values for heats of combustion
- Sample is ignited using electrically heated wire
- Excess oxygen ensures complete combustion of sample
- Heat produced by rapid + complete combustion of the sample heats, water + temperature is recorded
- Apparatus is well insulated to prevent heat loss
- Amount of heat used to start burning can be calculated and removed