All Flashcards
Hess’ Law
∆H is independent of the route it takes
Equilibrium
Rate of forward reaction + backward reaction is equal.
conc of R+P are constant
Henri Le Chatelier
In a closed system
If you inc/dec the T/P/C
It causes a shift in Equilibrium
To oppose the I/D in T/P/C
Increase Conc(R)
Equilibrium shift to RHS
Increase Pressure
Equilibrium shifts to side with less moles
Increase temperature (exothermic -∆H)
shift left
Endo
+∆H
Exo
-∆H
Enthalpy of Combustion
enthalpy change when 1 mole of a substance
is completely combusted in oxygen
and all R+P are in their standard states
Enthalpy of Formation
Enthalpy change when 1 mole of a substance
is formed from its constituent elements
and all R+P in their standard states
∆H Combustion
arrows towards box
∆H Formation
Arrows towards equation
Calorimetry
thermometer, copper can, water, spirit burner
Calorimetry Copper Can
Using a measuring cylinder, put 100 cm3 of water into a copper can
Measure and record the initial temperature of the water
Fill the spirit burner with test substance and measure and record its mass
Place the burner under the copper can and light the wick
Stir the water constantly with the thermometer and continue heating until the temperature rises by about 20 - 30°c and blow out the flame
Measure and record the highest temperature of the water
Measure and record the final mass of burner and remaining alcohol
Calorimetry equation
q=mcΔT
Electrophile
An electron pair acceptor
Nucleophile
An electron pair donor
Test for Alkenes
bromine water orange to colourless
Test for carboxylic acid
sodium hydrogen carbonate with effervescence of CO2
Test for aldehydes
Fehling’s (Copper sulfate and sodium hydroxide) blue to red, ketones NVC
Test for alcohols
Add acidified potassium dichromate, warm gently, under reflux
primary- orange to green (aldehyde)
secondary- orange to green
tertiary- X
Why don’t tertiary alcohols oxidise?
You would have to break a C-C bond which takes a lot of energy, too much energy+money
Carbocationes (CCN)
Positively charged organic ions
Most stable is the CCN with 3 R hydrocarbon chains, also major product
Minor product is CCN with least number of R chains
