Developing Fuels Flashcards
What are standard conditions?
298K, 1atm, concentration of 1moldm-3
Define standard enthalpy of combustion.
One mole of a substance burnt completely in oxygen.
Define standard enthalpy of formation.
One mole of a compound formed from its elements.
Define standard enthalpy of neutralisation.
One mole of hydrogen ions react with one mole of hydroxide ions to form one mole of water.
Describe homogeneous catalysts.
Reactants and the catalyst are in the same physical state.
Describe heterogeneous catalysts.
Different physical states.
Reactants are adsorbed onto the surface, bonds are weakened and break. New bonds form. Products diffuse away.
Describe catalyst poisoning.
Poison molecules are adsorbed more strongly than the reactants. The catalyst becomes inactive.
What are the conditions of electrophilic addition for HBr, H2O and H?
HBr: room temperature.
H2O: high temperature, high pressure, phosphoric acid catalyst.
H: nickel or platinum catalyst.
Define structural isomerism.
Same molecular formula, bonded in a different order.
Define stereoisomerism.
Same structural formula, arranged differently in the same space.
How is photochemical smog formed?
Ozone is a secondary pollutant, formed from a mixture of primary pollutants (oxides of nitrogens, hydrocarbons), oxygen and water vapour.
Describe catalytic converters.
Platinum or rhodium catalyst.
Air-petrol mixture must be carefully controlled.
240°C.
Poisoned by lead.
Particulates are removed by diesel particulate filters.
Describe aromatic hydrocarbons.
Higher CO, hydrocarbons and nitrogen oxide emissions.
Describe natural gas.
Mainly methane, not under pressure. Cooled to -160°C. Less CO and nitrogen oxides.
Describe ethanol as a biofuel.
Crops are fermented.
Too volatile to be used alone.
Carbon neutral.
