last min organic

empirical vs molecular formula

An empirical formula is the simplest ratio of atoms of each element in the compound

A molecular formula is the actual number of atoms of each element in the compound

shape names of the following bps and lps:

3,0 + 3,1 + 5,0

trigonal planar, trigonal pyramidal, trigonal bipyramidal

standard enthalpy change of formation

enthalpy change when 1 mole of the compound is formed from its elements under standard conditions (298K and 100kpa), all reactants and products being in their standard states

standard enthalpy of combustion

enthalpy change that occurs when one mole of a substance is combusted completely in oxygen under standard conditions. (298K and 100kPa), all reactants and products being in their standard states.

if temp increases in calorimetry experiment, is rxn endo or exo?

exo so the value is negative

mean bond enthalpy def

enthalpy needed to break the covalent bond into gaseous atoms, averaged over different molecules

x and y axis of MB graph?

x - energy

y - number of molecules

features of dynamic eqm

1. Forward and backward reactions are occurring at equal rates

2. The concentrations of reactants and products stay constant

structural, chain, position, functional group isomerism defs

Structural isomers: same molecular formula different structural formula

Chain isomers: Compounds with the same molecular formula but different carbon chain lengths

position isomers: Compounds with the same molecular formula but have different positions of the same functional group on the same carbon skeleton

Functional group isomers: Compounds with the same molecular formula but different functional groups

petroleum fraction def

mixture of hydrocarbons with similar bps

economic reason for cracking

fractions w shorter C chains are in shorter supply and larger demand (cracking helps supply meet demand)

thermal vs catalytic cracking conditions

thermal: high pressure, high temp (600-900)

catalytic: moderate pressure, 450, zeolite catalyst

what can soot cause

global dimming

plasticiser function

weakens imfs in polymers, makes them more flexible

disadvantages of fermentation to make ethanol

batch process - slow + high production costs

less pure than direct hydration (which is a continuous process) so needs purifying by frac. dist.

why KCN better than HCN in nuc. add.

KCN strong acid - higher conc of CN- ions as KCN fully ionises

HCN is toxic gas + hard to contain

acid ester hydrolysis: eq, reagent, conditions

CH3CH2COOCH2CH3 + H2O → CH3CH2COOH + CH3CH2OH

dilute HCL, heat under reflux

reversible rxn

alkali ester hydrolysis

CH3CH2COOCH3+ NaOH → CH3CH2COO-Na+ + CH3OH

dilute NaOH, heat under reflux

non-reversible - anion resistant to nucleophilic attack

can add strong acid (HCL) to carboxylic acid salt to make it a carboxylic acid

terylene, nylon 6,6 monomers

benzene-1,4-dicarboxylic acid + ethane-1,2-diol (polyester)

hexanedioic acid + haxane-1,6-diamine (polyamide)

what happens when substrate is chiral?

only one enantiomer will have correct stereochemistry in the stereospecific active site of the enzyme so only one isomer will be catalysed

column chromatography

column is packed with a solid and solvent moves down column

stationary phase is silica/alumina as a powder to increase SA

mobile phase is polar/non-polar solvent

gas chromatography

column packed with solid OR solid coated by a liquid, and a gas is passed through the column under pressure at a high temp

mobile phase is inert gas like N2, He, Ar - wont react with components being separated

stationary phase is a high bp liquid on inert solid

factors affecting retention times in GC

temp of GC column, column length, flow rate