| why are unsaturated compounds more reactive that saturated compounds? | carbon atoms can bond to other atoms across the double bond in unsaturated compounds |
| what are the alkenes? | a homologous series of hydrocarbons that contain at least one carbon-carbon double bond |
| what is the first member of the alkene family? | ethene
there must be a minimum of 2 carbon atoms present to have a double bond present |
| what is the general formula for alkenes? | CnH2n |
| what are alkenes used for? | making plastics, ethanol and ethanoic acid, pesticides, medicine, toiletries and cosmetics |
| are alkenes soluble or insoluble in water | insoluble |
| what is a functional group? | an atom, group of atoms or types of bonds within a molecule that gives the compound its characteristic chemical properties |
| what is the functional group of an alkene | carbon to carbon double bond |
| what is an addition reaction | when two molecules combine to form a single molecule
it generally involves a multiple bond |
| what is hydrogenation? | the addition of hydrogen to a carbon to carbon multiple bond to form the corresponding alkanes |
| what happens when alkenes undergo addition reactions with halogens | halogenation
a halogenoalkane (dihaloalkane) is formed |
| what happens when alkenes undergo addition reactions with hydrogen halides? | a halogenoalkane (haloalkane) is formed |
| what is a hydration reaction? | an addition reaction where water is added to an alkene to produce an alcohol
this reaction is carried out using a catalyst and water in the form of steam |
| what is an isomer? | compounds with the same molecular formula but different structural formulae, may belong to
different homologous series and usually have different physical properties |
| cycloalkanes and alkenes with same number of carbon atoms are ___ of each other | isomers |
| name this molecule | 3-methylbut-1-ene |
| name this molecule | 2-methylhex-1-ene |
| define viscosity | a measure of how thick or runny a substance is
a viscous substance is thick and syrupy
a substance that isn't viscous is runny |
| what is flammability | a measure of how easily a substance will ignite
high flammability means the substance will ignite easily |
| what is volatility | a measure of how easily a substance will evaporate
low volatility means it will not evaporate easily |
| name 5 physical properties that show a trend as you go down a homologous | boiling point
volatility
flammability
viscosity
colour |
| describe the trend in boiling point as you go down a homologous series | boiling point increases down a homologous series because as the size of a molecule increases, (more carbon atoms, longer carbon chain) there are more intermolecular forces of attraction between molecules, thus requiring more energy to separate. |
| describe the trend in volatility as you go down a homologous series | volatility decreases as you go down a homologous series because as molecules get larger there are more intermolecular forces that need to break in order to evaporate, requiring more energy |
| describe the trend in flammability as you go down a homologous series | flammability decreases as you go down a homologous series because molecules have to evaporate and mix with oxygen before they can burn. Larger molecules require more energy to evaporate due to stronger intermolecular forces and are therefore less flammable. |
| describe the trend in viscosity as you go down a homologous series | viscosity increases down a homologous series as the longer chains become entangled, making it harder for the molecules to move past each other, and so they do not flow as freely as smaller molecules |
| why are unsaturated compounds more reactive that saturated compounds? | carbon atoms can bond to other atoms across the double bond in unsaturated compounds |
| what can alkenes undergo addition reactions with? | halogens
hydrogen
hydrogen halides
water |
| what happens in an addition reaction | the double bond is broken and a saturated product is formed
the molecule has added across the double bond |
| what happens to the halogen when naming carbon compounds containing halogen | the halogen becomes the functional group and the name endings change
fluorine - fluro
chlorine - chloro
bromine - bromo
iodine - iodo |
| how many products can a hydrogen halide give if the double bond is not in the middle of the alkene molecule? | two possible products, as it can add across the double bond in two different ways |
| name this compound | bromoethane |
| name this compound | 1,2-dichloroethane |
