Arenes - physical properties, naming and reactivity Flashcards Preview

A2 Chemistry D > Arenes - physical properties, naming and reactivity > Flashcards

Flashcards in Arenes - physical properties, naming and reactivity Deck (7)
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1
Q

How does the boiling and melting points of benzene compare the hexane?

A

benzene is a colourless liquid at room temperature

there is a 1 K difference in the boiling point of hexane (354 K) and benzene (353 K)

but its melting point (279 K) is much higher than hexanes (178 K)

2
Q

What causes the difference in melting point?

A

benzene’s flat, hexagonal molecules pack together very well in the solid state and are therefore harder to separate

this must happen for the solid to melt

3
Q

How are substituted arenes given a name?

A

named as derivatives of benzens

so benzene forms the root of the name

e.g. methylbenzene, C6H5CH3

4
Q

What happens if there is more than one subsituent? How is it named?

A

the ring is numbered

the first substituent in always given the number 1

e.g. 1,2-dimethylbenzene - C6H4(CH3)2

5
Q

How does the ring of delecolalised bonding affect the reactivity?

A

the ring is an area of high electron density

therefore it is attacked by electrophiles

6
Q

How does the ring almost always remain intact?

A

the aromatic ring is very stable

it needs energy to be put in to break the ring before the system can be destroyed

this is called the delocalisation energy

7
Q

How do arenes mostly react?

A

electrophillic substitution