general knowledge

Question 1

amylose

Answer 1

starch. a glucose, linear structure, rarely branches
C 1-4 glycosidic bonds

Question 2

amylopectin

Answer 2

starch. a glucose, highly branched (every ~24-30 units)
C 1-4 glycosidic bonds and C 1-6 for branching units

Question 3

cellulose

Answer 3

b glucose, unbranched, linear structure

Question 4

glycogen

Answer 4

a glucose, most branched (every ~8-12 units)

Question 5

glycosidic bond

Answer 5

bond between monosaccharides R-C-O-C-R’

Question 6

peptide bond

Answer 6

bonds between amino acids CONH

Question 7

empirical formula of monosaccharides

Answer 7

CH2O

Question 8

diff between a-glucose and b-glucose

Answer 8

rotation of carbon 1
a: hydroxyl below
b: hydroxyl above

Question 9

how to make a buffer solution

Answer 9

weak acid with a base as the limiting reagent

Question 10

when does an indicator change colour

Answer 10

when Pka = pH i.e. [HIn]=[In-]

Question 11

what are the properties of an ideal standard solution for titrations

Answer 11

needs: stable, high purity substance, highly soluble, high molar mass, known chemical formula, doesnt react with atmosphere

Question 12

more negative reduction potential means…

Answer 12

substance will be oxidised, acts as anode

Question 13

difference between cis and trans isomerism

Answer 13

cis: same side
trans: opposite side (cos they swap genders)
(both geometric isomers)

Question 14

a helix vs b pleated sheets

Answer 14

helix - H bonding within chains (intrachain)
pleated sheets - H bonding between chains (interchain)
helix - flexible
sheets - rigid, strong

Question 15

saponification

Answer 15

triglyceride + NaOH. glycerol broken off triglyceride and Na attached, condensation reaction.

Question 16

how do micelles work

Answer 16

soap has: hydrophobic tail (Carbon chain), hydrophilic head (COONa)

tails of soaps attracted to oil while head attracted to water, soaps align and cluster together forming a circular micelle which traps oils.

Question 17

why doesnt soap work in hard water

Answer 17

because Ca and Mg have a greater ionic charge (2+) than Na (1+), Na is taken off soap and replaced with Ca or Mg. this forms non-polar insoluble salts.

Question 18

how to tell between aldehyde and ketone using mass spectroscopy

Answer 18

if peak at m/z 29 -> COH therefore aldehyde

Question 19

how does gel electrophoresis work

Answer 19

separates molecules based on polarity, more polar molecules move further across gel.

Question 20

atom economy

Answer 20

(molar mass of desired product)/
(total molar mass of reactants)

Question 21

difference between LDPE and HDPE

Answer 21

LDPE: highly branched -> lower BP/MP
HDPE: minimally branched -> higher BP/MP

Question 22

syntactic vs atactic vs isotactic

Answer 22

alternating (sine wave) vs random vs same side

Question 23

henderson hasselbach equation

Answer 23

pH=Pka + log ([A-]/[HA])

Question 24

difference between spontaneous and non spontaneous redox reactions

Answer 24

spontaneous occurs in galvanic cell. cell potential is positive
non-spontaneous occurs in electrolytic cell. cell potential is negative.