4916931
Description
Flashcards by reegan.oravecz, updated more than 1 year ago
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Created by reegan.oravecz
about 8 years ago
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| Question | Answer |
| What is a halogenakane | they have an lake skeleton with one or more halogen atoms replacing a hydrogen atom. |
| What is the general formula for haloalkanes | CnH2n+1X |
| what is the formula shortened too | R-X |
| What are the prefix which tells us which halogen is present | fluoro, chloro, bromo, and iodo |
| what do we use to tell us where the halogen is present ? | numbers showing which carbon it is on |
| what prefixes are used to show how many of each halogen there is | di, tri, tetra |
| When a compound contains different halogens how are they ordered | in alphabetical order |
| what bond does halogenalkanes have | C-X bond |
| the C-X bond is polar. What does this mean | halogens are more electronegative than carbon. (delta -) on halogen. (delta +) on the carbon |
| as you go down the halogen group what is the trend in polarity? | they get less electronegative |
| Why aren't halogenalkanes not soluble in water? | because the polar bonds aren't polar enough to make it soluble in water |
| what is the main intermolecular forces of attraction? | dipole-dipole attraction and Van der waals forces |
| why can halogenalkanes be used as dry cleaning fluid to remove oily stains | because they mix with hydrocarbons and oil is a mixture of hydrocarbons |
| what does the boiling point of haloalkanes depend on | the number of carbon atoms and the number of halogen atoms |
| What 2 factors increase the boiling point? | with an increased chain length and increases going down the halogen group. |
| What are these boiling points effects caused by and why | an increase in Van der waals forces because the larger the molecule the greater the number of electrons |
| What tends to lower the melting point | increased branching of the carbon chain |
| why do halogenalkanes have higher boiling points than alkanes with similar carbon chain lengths? | because halogenlakanes have higher relative atomic masses and are more polar therefore there is an increase in Van der waals |
| when haloalkanes react what is most likely to break | C-X bond |
| what two factors determines how readily the C-X bond reacts? | bond polarity bond enthalpy |
| Why can the bond polarity be attacked by nucleophiles? | because it is electron deficient so nucleophiles which are electron pair donors can easily attack the carbon bonded to the halogen as it has a slight positive charge. |
| Thinking about bond polarity only, what would we predict to be the most reactive and least | C-F most C-I least |
| Whats the trend in enthalpies | bonds get weaker going down the group as bond enthalpies gets lower. |
| What is the smallest atom of the halogens | fluorine |
| why do bonds get weaker going down the group | because the shared electrons get further away from the nucleus |
| what would bond enthalpies predict with reactivity | iodo compounds would be most reactive n and fluoro compounds would be the least reactive |
| what is the actual reactivity trend and what does this mean | reactivity increases going down the group therefore bond enthalpy is a more important factor than bond polarity |
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