Question | Answer |
What are the products of hydrolysis of Amides | Carboxylic acid and an amine. |
Why are Amides soluble in water? | Amides can form Hydrogen bonds with water (stronger H-bonds than Carboxylic acid with water) |
What type of reaction produces Amides from Carboxylic acid and an amine. | A condensation reaction |
Name CH3CH2CH2CONH2. | Butanamide |
What is the ph range of Amides? | 4–7 acidic to neutral. |
What is the ph range of Amines? | 8–12 Basic. |
What is the product of Amines react with acids? | An ammonium salt. |
Describe how you would convert an ammonium salt to an amine | Add a weak base to remove the extra H+ |
Explain why are amides not basic | Where the lone pair on the N on Amines accept the additional H from water and leave OH– in the solution, Amides do not. |
What happens to H3CNH2 in water? | H3CN+H3 forms (the positive charge is on the N) |
Why do Amides not undergo hydrolysis at room temperature? | They are very stable. |
How can hydrolysis of an Amide be promoted? | Through the addition of strong acid or a strong base. |
What are the products of acidic hydrolysis of Amides? | Ammonium salt and Carboxylic Acid ( because excess H+ ions allow ammonium ions (N+H4) to form instead of ammonia) |
What are the products of alkaline hydrolysis of Amides? | Amine and Carboxylate salt ( because Excess OH- will react with Carboxylic acid to form the carboxylate salt) |
What is the product of Acid chlorides react with Amines? | HCl and Amides without a salt being formed. |
How are peptides formed? | By the condensation reaction between amino acids, forming a long chain molecule. |
What is a polyamide? | Polymers resulting from the formation of amide bonds. |
Describe how to draw a condensation polymer | Draw two molecules, placing the COOH and teh NH2 in front of one another, remove H2O, join the C=O and the NH |
How would you name the –NH2 group in a compound? | amino |
Describe a Quaternary ammonium salt | Ammonium salt where all four groups attached to the nitrogen atom are hydrocarbon groups. |
What is the naming convention for amides | Count the number of Carbon for the “backbone”. Carboxylic acid name, with the –oic acid becoming –amide: ex: Ethanamide |
Are amides acidic, basic or neutral | Fairly neutral. They do not act as bases as strongly as amines, because their nitrogen is bonded to the carbonyl carbon, which influences the lone pair on the nitrogen and prevents it from accepting a proton. |
What is the product of a Carboxylic acid with ammonia? | a PRIMARY amide |
What is the product of a Carboxylic acid with CH3NH2? | a SECONDARY amide |
What is the product of a Carboxylic acid with a amine like (CH3)2NH? | a tertiary amide |
What are the condition for the reaction of a carboxylic acid and an amine? | high temperature/reflux |
Describe 3 features of addition polymerisation? | 1) there is no bi product 2) they are formed from the same monomers 3) it involves breaking a c=c |
Describe 3 features of condensation polymerisation? | 1) there is a bi product, eg. 2nH20\n2) they are formed from different monomers\n3) the monomers have two functional groups (di) |
What are the reactants to make polyester? | diol and dicarboxylic acid |
What are the reactants to make polyamide? | a diamine and a dicarboxylic acid |
What are the reactants to make polypeptide? | two AMINO-ACIDs |
Describe 3 features of Nylon (synthetic polyamide) | 1) it is stress resistance\n2) strong – due to H bonds\n3) H bonds cause long single chains to twist into fibers. |
Describe 2 features of Kevlar (synthetic polyamide) | 1) it is resistant to high pressure\n2) rigid due to benzene ring |
CHALLENGE: Evaluate the use of using a diacylchloride to form Nylon rather than a carboxylic acid | benefit: The reaction is faster, however disadvantage: the bi product if acidic fumes of HCl instead of h20 |
CHALLENGE: Why cant addition polymers biodegrade? | They have non–polar c–c and c–h bonds, hence they are very unreactive. They do not hydrogen bond with water. They cant be broken down by hydrolysis. |
Why can condensation polymers biodegrade? what are the conditions/ reagents for this breakdown process (x2) | They can be broken down by hydrolysis into their monomers, but the reaction is slow. \nReagents: NaOH conditions: aqueous \nOR \nReagents: add (2n)H20 conditions: hcl/h2so4 and heat |
Evaluate the benefits and problems of disposal by burying them (landfill sites) | good: this is useful when its difficult to separate the plastics/recycle and it is a cheap and easy method. bad: we are running out of landfill sites and some decomposed plastics/waste can release methane (ghg) which could contaminate water supplies |
Evaluate the benefits and problems of disposal by burning the plastics | good: the heat energy generated can be used to make electricity\nbad: it can release toxic gases such as hcl or waste gases such as co2 which contribute to global warming |
Evaluate the benefits and problems of disposal by recycling the plastics | good: it conserves non–renewable resources such as oil. The plastic can be cracked into its monomers or melted down and remoulded. Bad: plastics need to be sorted; some plastics are mixtures of polymers and can not be recycled |
Describe the synthesis of an aliphatic amine and why an excess of ammonia is required. | aliphatic amines prepared by nucleophilic substitution using a halogenoalkane and excess ammonia using heat and ethanol as a solvent. Excess ammonia is necessary to prevent further substitution occurring which would produce secondary or tertiary amines. |
Name a tertiary amine | any i.e. trimethylamine, (CH3)3N |
Explain the basicity of amines in terms of proton acceptance by the nitrogen lone pair | Amines are weak bases so they are proton acceptors. Each amine has a lone pair of electrons on the nitrogen atom so they can accept a proton. A dative covalent bond forms between the lone pair of the nitrogen atom and the proton. |
What is meant by an alpha-amino acid? | An amino acid in which the COOH group and the NH2 group are attached to the same carbon atom (the aplha-carbon). |
What is meant by a dipeptide? | A compound containing two amino acids linked together by peptide bonds (CONH). |
Alanine is the simplest alpha- amino acid, give its empirical formula. | C3H7NO2 |
Explain the difference between a condensation and addition polymer | An addition polymer is a monomer with a double bond that is removed to form a single bond polymer. A condensation polymer is the joining of 2 monomers with the removal of a small molecule (H20) |
How does CH3CH(NH2)CH2CH3 act as a base? | The NH2 can accept a proton due to the lone pair of electrons on the 'N' forming NH3+ |
Define alpha amino acid. | An alpha amino acid has an NH2 and OOH group on the same carbon atom |
How do you form aliphatic amines? | Heat a haloalkane with an excess of ethanolic ammonia under pressure. |
Describe the structure of DNA | |
What are the matching pairs of bases and how many hydrogen bonds can each pair for? | |