6167652
Description
Flashcards by Monica Rodrigues, updated more than 1 year ago
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Created by Monica Rodrigues
over 7 years ago
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| Question | Answer |
| How are σ-bonds formed? | When orbitals overlap end to end directly between two nuclei |
| How are π-bonds formed? | When p-orbitals overlap sideways above and below direct line between the atoms |
| What are stereoisomers? | Have the same structural formula but different arrangement of atoms in space |
| What is a structural isomer? | Compounds with the same molecular formula but different structural formulae |
| Why is rotation not normally possible around a C=C double bond? | Rotation would break the π-bond (destroy the sideways overlap of the p-orbital) which requires too much energy at room temperature |
| What features must be present in a molecule if it can exist as a pair of E/Z isomers? | > A double bond > Each of the double bonded carbon atoms must also have different groups bonded to it |
| What does a curly arrow signify? | The movement of a pair of electrons |
| What is the meaning of the term electrophile? | Attraction of a pair of electrons. Electron pair acceptor |
| What type of bond-breaking occurs during electrophilic addition? | Heterolytic fission > Double bonds in alkenes are broken to enable other atoms to be added to the carbon atoms |
| The cheapest way of disposing decommissioned polybutylene is to bury it in landfill. What is the disadvantage of this? | > Landfills require space. Can be an eyesore as well as damage existing wildlife habitats > Alkene plastics are not biodegradable so more and more land will be needed |
| 3 alternative methods of dealing with the waste polybutylene, which are more sustainable than burial in landfill? | > Recycle/ reuse > Use as feed-stock for cracking to produce alkenes (for fuel) and alkenes (for making other polymers) > Combustion to give heat to generate electricity |
| What is the systematic name of PVC? | Poly(chloroethene) |
| PVC can be disposed of by combustion, provided precautions are taken to prevent pollution problems. Why? | > Chlorinated plastic such as PVC produce hydrogen chloride gas which is toxic as it produces hydrochloric acid when it dissolves in the moisture of the lungs > However, this can be removed by passing the waste gases through aqueous alkali |
| What does biodegradable mean? | Can be broken down by living organisms |
| What does photodegradable mean? | Can be broken down by exposure to light |
| What are the advantages of polymers being biodegradable or photodegradable? | The plastics would not accumulate in the environment (on land or at sea) where these may be eaten by animals or be an eyesore |
| Conditions for HALIGANATION with a HALOGEN? | > Halogen > Does not need UV light can occur in the dark |
| Conditions for HALIGANATION with a HYDROGEN HALIDE? | > Dissolve alkene in non-polar solvent > Bubble hydrogen halide through alkene |
| Conditions for HYDROGENATION reaction? | > Nickel catalyst > Heat around 60°C |
| Conditions for HYDRATION reaction? | > Steam > 300°C > 60atm > Phosphoric acid catalyst |
| What is Markownikoff's rule used for? | Find out the stability of carbocations which is used to predict the major product in an electrophilic addition mechanism |
| Primary carbocation | Has atleast 2 or more hydrogens attached |
| Secondary carbocation | Only has 1 hydrogen attached to it |
| Tertiary carbocation | Has no hydrogens attached |
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