Chemistry Flashcards
Antacid
A weak base
Arrhenius Theory
Acid - proton donor
Base - hydroxyl donor
Brønsted-lowry theory
Acid - proton donator
Base - proton acceptor
Water is amphoteric
Strong acid- strong tendency to give up proton
Weak acid- weak tendency to give up proton
Lewis theory
Lewis acid - electron pair acceptor
Lewis base - electron pair donor
Both combine to make adduct
Uses valence electron (outer e-)
pH and [H3O+] equation?
pH= -log[H3O+] [H3O+]= 10-pH
Kw equation and what is it at 25°C?
Kw= [H3O+][OH-]
25°C kw is 1x10-14
Strong acids? Strong base?
HCL HBr HI H2SO4
NaOH KOH
Weak acid? Weak base?
Acetic acid (ethanoic acid) HF H2O
NH3 HS- H2O
Ka and pKa equation?
Ka= [H3O+][A-] ÷ [HA]
pKa= -logKa Ka= 10-pKa
Acid strength of pKa?
The stronget the acid the lower the pKa
The weaker the acid the higher the pKa
pH and pKa ionisation?
Acids pH = pKa 50% ionized pH = pKa +1 90% pH = pKa +2 99% pH = pKa +3 99.9%
Base pH = pKa 50% pH = pKa -1 90% pH = pKa -2 99% pH = pKa -3 99.9%
What is pKa?
Measure of how easily a molecule will release a proton
Electronegativity?
The ability of an atom to pull bonding electrons towards itself. F is most electronegative
Hybridization
Promoting an electron to an empty p orbital to form an sp3 orbital
2e- = linear = 180° = sp 3e- = trigonal planar = 120° = sp2 4e- = tetrahedral = 109.5° = sp3
Single bond is sigma
Double bond is one sigma and one pie bond
Buffer?
The ability to resist changes in pH upon the addition of small amounts of either acid or base
Equivalence point is when the pH and Base are at the same point
Henderson Hasselbalch equation
pH = pKa + log ([conjugate base] ÷ [acid])
Alkane pKa
> 50
Alkynes pKa
44
First law of thermodynamics
Energy can’t be created or destroyed, it can only be converted from one form to another
Energy equation
Change in energy = final - initial
Exothermic and Endothermic
A change that releases heat = decrease in enthalpy (negative number)
A change that absorbs heat = increase in enthalpy (positive number)
Heat capacity equation
Q= C x change in T
Rate equation and arrhenius equation
Rate = k[A]n[B]m
K = Ae^(-Ea/RT)
Alcohol pKa
15.5-18
Water is 15.7
How to prioritise atoms attached naming it R/S?
Drawn in 3D Prioritise using atomic number Make sure 4th atom at back Clockwise = R Anticlockwise = S
2 exceptions for enantomers?
Plane polarised light filters it
Optical activity
Meso stereoisomers
Molecules with 2 identical chiral carbon atoms have 3 stereoisomers
Separating enantiomers?
Resolution- separation from racemic mixture or enantiomerically enriched mixture. One crystallised and filtered and other evaporated
Chiral chromatography- racemic solution is passed over chiral stationary phase giving rapid and reversible diastereotopic interaction
Lipinski rule?
No more than 5 h bond donors
No more than 10 h bond acceptors
Molecular weight under 500 dalton’s
Partition coefficient log P less than 5
Used for assessing drug likeness and suitability for oral administration
Phenol pKa
10
Carboxylic acid pKa
4.8
Anomer
2 sugars that’s differ in configuration at the carbon that’s the C=O in the open chain form
Separation of amino acids?
pI separation by electrophoresis
By polarity - chromatography
In exchange chromatography
Amide pKa
Neutral 35
RCO2H 5
Semi-synthetic substance
Some compounds either can not be purely synthesized or can not be isolated from natural sources in low cost. Therefore, the natural intermediate of such drugs could be used for the synthesis of a desired product
HCl pKa
-7
Inductive effect
An atoms ability to polarise a bond
can cause polarisation
pH of abdomen
Stomach - 1-3
Small intestines - 6-7.5
Large intestines - 7-8
Colon - 5-7
Carboxylic derivative reactivity order
OH (carboxylic acid) Cl (acid chloride) OC(O)R' (anhydride) OR' (ester) NR2 (amide)
water pKa
15.7
H3O pKa
-1.7
Single, double and triple
Single - sigma
Double - 1 sigma, 1 pie
Triple - 1 sigma, 2 pie
SN1 vs SN2
SN1 forms and intermediate whereas SN2 doesn’t
Second law of thermodynamics
Entropy of the universe increases in a spontaneous process and remains unchanged in an equilibrium process
HLB
more soluble in water if more than 10