amines and amides

Question 1

define a ligand

Answer 1

a molecule or ion with a lone pair of electrons which can make a dative covalent bond with a metal cation forming a complex ion

Question 2

what state are short chain primary amines at room temp

Answer 2

gas

Question 3

why are short chain primary amines soluble in water

Answer 3

H bonds are possible between the amine H+ attached to the electronegative N atom and lone pair on H2O. also between RN:H2 and +H20

Question 4

define a base

Answer 4

a proton acceptor

Question 5

how does ammonia react with water to produce a basic solution (equation)

Answer 5

N:H3 +H20 –> NH4+ + OH-
(OH- makes the solution alkaline)

Question 6

order of base strength (from lowest to highest)

Answer 6

phenylamine < NH3 < primary < secondary < tertiary

Question 7

why is butylamine a stronger base than ammonia

Answer 7

alkyl group is weakly electron donating to lone pair on N. increases the electron density of the lone pair and makes it more available to a H+ ion

Question 8

why is phenyl amine a weaker base than ammonia

Answer 8

N lone pair overlaps with the delocalised ring of the benzene group. this increases the electron density of the ring, reduces the electron density of the N lone pair. It is now less attractive to H+ ions.

Question 9

which kind of mechanism is the preparation of amines with halogenoalkane and ammonia

Answer 9

nucleophilic substitution

Question 10

why can ammonia act as a nucleophile

Answer 10

lone pair on the N

Question 11

reaction details of ammonia and halogenoalkane (reagents and conditions)

Answer 11

reagents: halogenoalkane + excess conc ammonia dissolved in ethanol
conditions: heat in a sealed tube

Question 12

what are the two steps of preparing amines from a halogenoalkane and ammonia

Answer 12

step 1: ammonia acts as a nucleophile
step 2: acts as a base releasing the free amine

Question 13

what kind of reaction is the preparation of amines with a nitrile

Answer 13

reduction

Question 14

what are the two ways of producing an amine from a nitrile

Answer 14

1 using hydrogen gas and a nickel catalyst

2 using LiAlH4 in dry ether followed by dilute acid

Question 15

equation for reduction of nitrobenzene to phenyl amine

Answer 15

C6H5NO2 +6[H] -> C6H5NH2 + 2H2O

Question 16

What is the reducing agent for the reduction of nitrobenzene to phenyl amine

Answer 16

Tin and concentrated HCl

Question 17

step 1 of reduction of nitrobenzene to phenyl amine

Answer 17

add tin to nitrobenzene
add conc HCl with cooling
heat on a boiling water bath to complete the reduction

Question 18

step 2 of reduction of nitrobenzene to phenyl amine

Answer 18

sodium hydroxide added
collect phenyl amine by steam distillation
shake with NaCl solid
separate organic layer
dry with K2CO3 solid
redistill using an air condenser

Question 19

what is the functional group of an amine

Answer 19

R-NH2

Question 20

what is the functional group of an amide

Answer 20

R-C=ONH2

Question 21

which intermolecular forces do amides contain

Answer 21

London forces and H bonding

Question 22

are amides soluble in water

Answer 22

yes due to H bonds

Question 23

why are amides less basic than amines

Answer 23

in amides the lone pair is delocalised between the nitrogen and the oxygen due to resonance. This reduces the electron density on the nitrogen atom.

Question 24

what kind of reaction is the preparation of amides

Answer 24

nucleophilic substitution

Question 25

what are the 2 ways of preparing an amide

Answer 25

1 acyl chloride + ammonia
2 acyl chloride + amine