Karteikarten
Chemistry As Unit 2 FLASHCARDS
Karten in diesem Stapel (18)
- 1two factors that affect the contribution of a greenhouse gas to global warming1.atmospheric concentration
2.ability to absorb I.R. radiation - 2two methods developed to achieve carbon capture and storage1.storage of carbon dioxide under pressure on the sea bed.
2.reaction of carbon dioxide with metal oxides to form stable carbonate minerals
3.liquefy the carbon dioxide and pump it into old gas wells in the North Sea - 3two ways in which the use of catalysts helps chemical companies to make their processes more sustainable.1.catalysts allow for the reaction to proceed in lower temperature which makes it cheaper->les fuel is used up so less pollution
2.catalysts are used but not used up in the reaction
3.different reactants can be used ith better atom economy due to the specific nature of catalysts which increases efficiency - 4two reasons why there is still concern about ozone depletion->CFCs are still being used
->takes many years for the ozone to recover - 5why 1-iodopropane is hydrolysed faster than 1-bromopropane->C-I bond is longer and weaker than C-Br so is more easily broken so 1-iodopropane is hydrolysed faster
- 6two ways in which polymers are procesed usefully rather thsn just dumped in landfill sites1.Combuston for energy production
2.separation into type followed by recycling - 7suggest why the average bond enthalpy of a C=C bond is not twice the bond enthalpy of a C-C bond->because sigma bonds are stronger than pi bonds
- 8problem aused by dispoing of PTFE and PVC in this way?->they produce toxic gases
- 9describe two way in which chemists can reduce this enviromental damage1.developing biodagradable polymers
2.developing methods of storing and recycling - 10homologous seriesis a group of organic compounds with the same general formula and te same functionalgroup.
- 11fuctional groupis a group of atoms in a compoud that are responsible for the characteristic properties of that compound
- 12standard enthalpy change of reactinethalpy change tha takes place when the amounts of reactants shown in the equation react under standard conditions
- 13standard enthalpy change of forationenthalpy change when 1mole of a compud is formed under standard conditions
- 14standard entalpy change of combustionenthaly change when 1mole of an elementor compound is burned in excess oxygen under standard conditons
- 15the mean(averae)bond enthalpyis the mean amount of energy required to breack one mole of a particular type of covalent bond in the gaseous state
- 16why linear molecules have higher boiling points than branched moleculesthe arrangment of linear molecules means there are more areas of surface contact so more intermolecular forces which makaes the bonds harder to breack hence the boiling point is higher
- 17exothermic...
- 18activation energyis the minimum energy needed on collision for a reaction to take place
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