polymers and life

Question 1

define amphoteric

Answer 1

when a compound exhibits both acidic and basic properties

Question 2

what is a zwitterion?

Answer 2

an overall neutral molecule that has both a positive and negative charge in different places on the molecule

Question 3

what is the isoelectric point?

Answer 3

the pH at which the charge on the amino acid is 0

Question 4

What is an enantiomer?

Answer 4

mirror images/non superimposable

Question 5

What is the difference between normal light and plane polarised light?

Answer 5

Normal light vibrates in all directions, whereas plane polarised light vibrates in one direction

Question 6

How do optical isomers affect plane polarised light?

Answer 6

One enantiomer rotates light in a clockwise direction, the other rotates it in an anti-clockwise direction

Question 7

Describe a test for an amine

Answer 7

Add small amount of acyl chloride -> white fumes of HCl = amine

Question 8

Which functional group do amides contain?

Answer 8

-CONH2

Question 9

Why do amides behave differently to amines?

Answer 9

The presence of carbonyl group pulls electrons away from the rest of the group

Question 10

Which type of amide hydrolysis results in a carboxylic acid and ammonium salt?

Answer 10

Acid hydrolysis

Question 11

What type of amide hydrolysis gives a carboxylate ion and ammonia?

Answer 11

Basic hydrolysis

Question 12

How are nylons made?

Answer 12

In a condensation reaction between a diamine and a dicarboxylic acid

Question 13

What do x and y represent in nylon-x,y?

Answer 13

X= number of carbons in diamine 
Y= number of carbons in dicarboxylic acid

Question 14

what monomers are polyamides made from?

Answer 14

dicarboxylic acid and diamine

Question 15

what monomers are esters made from?

Answer 15

dicarboxylic acid and diamine

Question 16

why does the M+1 peak exist?

Answer 16

small proportion of organic molecules in a sample will contain 13 C carbon

Question 17

what is a test for carboxylic acid?

Answer 17

carbonates

Question 18

what is the difference between a primary and secondary amide?

Answer 18

primary amide directly bonded to one carbon whereas a secondary amide has N bonded to more than one carbon

Question 19

what are DNA and RNA examples of?

Answer 19

condensation polymers joined from nucleotides

Question 20

how does the phosphate-sugar backbone in DNA form?

Answer 20

phosphate joins by condensation with deoxyribose

Question 21

how do the bases in DNA join to the phosphate-sugar backbone?

Answer 21

condensation with the deoxyribose

Question 22

explain how helices and sheets are held together in secondary protein structure

Answer 22

hydrogen bonds between NH groups on one peptide link and c=o groups on another

Question 23

how does the ethanedioate ion behave as a ligand?

Answer 23

• bidentate ligand

- uses two lone pairs to form co-ordinate bonds to a central metal

Question 24

name a bidentate ligand (not ethanedioate or water)

Answer 24

-1,2-diaminoethane

Question 25

how does a ligand bond to a metal ion in a complex?

Answer 25

level 3 orbitals are organised so that there are 6 new orbitals with equal energy

Question 26

why does water form six co-ordinate bonds when it behaves as a ligand?

Answer 26

by making the maximum amount of bonds, it is most energetically stable

Question 27

what type of ligand is EDTA?

Answer 27

hexadentate

Question 28

how do you calculate rate from a curved graph?

Answer 28

draw tangent from steepest point

Question 29

how do you calculate the concentration of the salt in a buffer?

Answer 29

Ka x weak acid/ H+