AS preperation final notes Flashcards
When asked for definition involving mass?
Weighted mean mass of…
In comparison to 1/12th of the mass of an atom of C 12
First IE=
Energy required to remove
1 electron from each atom
In 1 mole of gaseous atoms
To form 1 mole of +1 ions
Orbital=
Region of space which can hold up to 2 electrons with opposite spin
Order of subshells
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6
Acid=
Releases H+ ions in solution
Proton donor
Base=
Compound which neutralises an acid, to form a salt
Proton acceptor
Alkali=
A soluble base, which releases OH- ions in solution
Silver ion
AG+
Ammonium ion
NH4+
Zinc ion:
Zn 2+
Carbonate ion
CO3 2-
Sulfate ion
SO4 2-
Nitrate ion
NO3 -
Phosphate ion
PO4 3-
Silver chloride =
White precipitate
Soluble in dilute and conc ammonia
Silver Bromide =
Cream precipitate
Soluble in conc ammonia, not dilute
Silver Iodide =
Yellow precipitate
Not soluble in ammonia
Writing an ionic equation:
Balanced equation with states
Split all aqueos solutions into ions
Cancel out anything which is aqueous on both sides
Rewrite
Sulphate ions test
Add Barium chloride
If present white precipitate forms
Carbonate ions test:
Add dilute Nitric acid, and bubble gas through limewater
If present goes cloudy
Ammonium ions test
Heat
Damp litmus paper goes blue
Ionic bonding=
Electrostatic attraction between positive and negative ions
Covalent bond=
Strong electrostatic attraction between
Shared pair of electrons
And nuclei of bonded atoms
Average bond enthalpy=
Average enthalpy change that occurs when:
Breaking by homolytic fission of 1 mole of a given type of bond
In molecules of a gaseous species
2 BP around central atom:
Linear
180
3BP around central atom:
Trigonal planar
120
4 BP around central atom
Tetrahedral
109.5
2 normal bonds and 2 different types of wedges
3 BP and 1 LP around central atom:
Pyramidal:
107
1 normal bond, 2 different types of wedges
2 BP and 2 LP around central atom
V shaped
104.5
2 normal bonds
6 BP around central atom:
Octahedral
90
2 normal, 2 of one type of wedge, 2 of other type of wedge
Electronegativity=
Ability of an atom to attract the bonding electrons in a covalent bond
Number of particles=
6.02x10^23 x moles
Formula involving mass molar mass and moles
Moles = mass / molar mass
Finding ratio in water of crystallisation
Find moles of solid
Find moles of water
Find ratio
Percentage error=
(Total uncertainty/ value measured) x 100
Formula for moles with conc and volume
Moles = concentration x volume
How to find volume of gas at rtp
Volume = 24dm^3 x volume
Ideal gas equation:
Pressure (Pa) x Volume (M^3) = moles x 8.314 x temp (kelvin)
Atmostpheres to pascals =
multiply by 100,000
Chlorine features:
Gas, green
Bromine features:
Liquid, brown
Halogens colour in water:
Cl = colourless/pale green Br = orange I= Orange
Halogens colour in hexane:
Cl = Green Br = Orange I = purple
Disproportionation reaction =
Oxidation and reduction of the same element
Homologous series =
A series of organic compounds having the same functional group
But each successive member differing by CH2
Functional group=
A group of atoms responsible for characteristic reactions of a compound
3 steps in radical substitution?
Initiation:
Br2 = 2Br@
Homolytic splitting via UV light
Propagation:
Br@ + CH4 = HBr + CH3@
CH3@ + Br2= CH3Br + Br@
Termination:
CH3@ + Br@ = CH3Br
Br@ + Br@ = Br2
CH3@ + CH3@ = CH3CH3
Describe Carbon single bond
End on overlap of atomic orbitals, producing a sigma bond
Describe a Carbon double bond
Second bond produced by sideways overlap of P orbitals to form a pi bond
Electrons above and bellow plane of atom
Stereoisomer=
molecules that have same structural formulae but different arrangements of atoms in space
When can E/Z isomerism occur?
Restricted rotation around double bond
Each C of double bonds has different groups attached
How to name E/Z isomerism
Functional groups on opposite sides=E
On same side= Z
Put these in front of name
Functional group= one with highest mass, includes everything bonded directly to nearest atom
How to name cis/trans bonding?
When 1 of the groups attached to each side of the double bond is the name
Same side= cis
Different sides= trans
Ethene + Hydrogen reaction
= Ethane
Requires 150 degrees and Ni catalyst
Ethene + Bromine=
Di-Bromoethane
Ethene + Hydrogen Bromide=
Bromoethane
Ethene + H2O=
Ethanol
Water is steam
Phosphoric acid catalyst
Electrophile=
An atom (or group of atoms), attracted to an electron rich centre, where it accepts electrons to form a new covalent bond
Drawing electrophilic addition
Draw Alkene with Hydrogen bromide bellow, with hydrogen being closer
Hydrogen is delta positive, bromide is delta negative
Draw curly arrow from double bond to hydrogen
Draw curly arrow from covalent bond in Hydrogen bromide, to the Bromide
Draw alkane, but one carbon is missing a hydrogen and C has a positive charge
Draw Bromide ion with lone pair, and a negative charge
Draw curly arrow from lone pair to positive Carbon
Draw molecule
Markownikoffs rule
Most likely product of electrophilic substitution is where Hydrogen bonds to C which is attached to the least amount of Carbons
Primary alcohol=
Carbon OH is attached to bonded to 1 Carbon
Secondary alcohol=
Carbon OH is attached to bonded to 2 Carbons
Tertiary alcohol=
Carbon OH is attached to bonded to 3 Carbons
Reflux=
Continues boiling and condensing of a mixture, to prevent loss of volatile components
Nucleophile=
An electron pair donor
How to draw nucleophilic substiution
Draw Halkoalkane, with C being delta + and Halogen being delta -
Draw an OH group with a lone pair and a negative charge
Draw curly arrow from lone pair to delta positive C
Draw curly arrow from Bond between Halogen and C to the halogen
Halogen replaced by OH producing a halide ion
Measuring reactivity of haloalkanes
Reagant= silver Nitrate solution
Conditions= Hot water bath and Ethanol as co solvent
Observe time for silver halide precipitate to form
Ionic equations for both steps
Trend iodoethane fastest, chloroethane slowest
Factor strength of C-Halogen bond
Explain why C-Cl is strongest
Dehydration of alcohols=
Heat under reflux
Catalyst of conc sulphuric or phosphoric acid used
Double bond formed, water produced
Colour change if an oxidation reaction successful?
Red to green
How to produce an aldehyde?
Add oxidising agent to primary alcohol
Gentle heating with distillation
What’s an aldehyde?
C double bonded to O, and bonded to a H
Ending = al
How to produce a carboxylic acid
Make aldehyde, add more oxidising agent and heat under reflux
Carboxylic acid=
C double bonded to an O
And C bonded to an OH
Ends in “oic acid”
How to produce a Ketone?
Add oxidising agent to a secondary alcohol
Heat under reflux
Ketone=
Carbon double bonded to O
Can tertiary alcohols be oxidised?
No, stays red
Esterfication=
Carboxylic acid + alcohol = Ester + water
Heat under reflux and sulphuric acid catalyst
Naming an ester:
First words ends in “yl”
Second word ends in “oate”
Longest alcohol C chain determines what’s in front of yl
Longest C chain in carboxylic acid goes in front of oate
How to find heat change, and enthalpy change?
Heat change (joules) = mass of solution x change in temp x 4.18
To find enthalpy change divide heat change by 1000
and then divide by the amount of fuel used
Units= kJ mol^-1
Standard enthalpy change of combustion:
1 mole of substance completely reacts with oxygen
Under standard conditions-
Standard enthalpy change of formation:
1 mole of compound is formed from it’s elements
Under standard conditions-
Standard enthalpy change of neutralisation:
:
Reaction of acid and alkali to produce 1 mole of H2O, under standard conditions-
Lattice enthalpy
Formation of 1 mole of an ionic compound, from it’s gaseous ions
Standard conditions
Atominsation enthalpy:
Formation of 1 mole of gaseous atoms from elements in standard states
Standard conditions
Electron affinity
One electron added to each atom of an element to form 1 mole of gaseous 1- atoms
Uses up an electron
Born haber cycle:
Start with elements in natural states
Go upwards atomise metal
atomise gas
all ionisation energies
all electron affinitys (worst one goes down)
Reach gaseous ions
Gaseous ions to ionic compound= lattice enthalpy
Elements in natural state to ionic compound = formation
Entropy
Measure of organisation
Entropy change (joules) = (Add up all S values of products) - (Add up all values of S values of reactants)
Gibbs free energy (negative it can happen)
Enthalpy change - (kelvin x entropy change)
CONVERT DEGREES TO KELVIN BY ADDING 273
CONVERT ENTROPY TO KJ BY DIVING BY 1000
Atom economy formula?
Atom economy = mass of atoms of desired products/ mass of atoms in reactants
