Chapter 21 - Fuels and Heats of Reaction Flashcards
Hydrocarbon
A compound that contains carbon and hydrogen only
Fossil fuels
Fuels that were formed from the remains of plants and animals that lived millions of years ago
Saturated compound
One in which there are only single bonds between the atoms in the molecule
Homologous series
A series of compounds of similar chemical properties
Showing gradations in physical properties
Having a general formula for its members
Each member having a similar method of preparation
Each member differing from the previous member by a unit
Structural isomers
Compounds with the same MOLECULAR formula but different structural formulas
Unsaturated compounds
One that contains one or more double or triple bonds between the atoms in the molecule
Aliphatic compound
An organic compound that consists of open chains of carbon atoms and closed chain compounds that resemble them in chemical properties
Aromatic compound
Compounds that contain a benzene ring structure in their molecules
Auto ignition
Premature ignition of the petrol-air mixture before normal ignition of the mixture by a spark takes place
Octane number
A fuel is a measure of the tendency of the fuel to resist knocking
Catalytic cracking
The breaking down of long chain hydrocarbon molecules by the action of heat and catalysts into short chain molecules for which there is greater demand
Heat of reaction
The heat change when the numbers of moles of reactants indicated in the balanced equation for the reaction react completely
Heat of combustion
A substance is the heat of change when one mole of the substance is completely burned in excess oxygen
Kilogram calorific value of a fuel
The heat of energy produced when 1kg of the fuel is completely burned in oxygen
Bond energy
The average energy required to break mole of a particular covalent bond and to separate the neutral atoms completely from each other
Heat of neutralisation
The heat change when one mole of H+ ions from an acid reacts with one mole of OH- ions from a base
Heat of Formation of a compound
The heat change that takes place when one mole of a compound in its standard state is formed from its elements in their standard states
Hess’s Law
If a chemical reaction takes place in a number of stages, the sum of heat changes in the separate stages is equal to the heat change if the reaction is carried out in one stage
Law of Conservation of Energy
Energy cannot be created or destroyed but can only be converted from one form of energy into another
Organic chemistry
The study of the compounds of carbon
Sources of hydrocarbons
Fossil fuels:
Coal
Methane
Crude oil
Methane
- Formed from materials of plant and animal origin, decayed manure (anaerobic bacteria)
- Heats the farm
- Contributes to greenhouse effect
