LEARN BEFORE EXAM Flashcards
v (3+)
GREEN
mno4-
purple
mno4 (2-)
green
cr2o7 2-
orange
vo2 (+)
yellow
vo (2+)
blue
ti (3+)
purple
v (3+ )
green
cr (3+)
violet
fe (3+)
yellow
ti (2+)
violet
v (2+)
violet
mn (2+)
PALE pink
fe(2+)
PALE green
co (2+)
pink
ni (2+)
green
cu (2+)
PALE blue
interconversion between fe2+ and fe 3+
fe 2+ ( pale green) oxidised to fe 3+ (yellow) by ACIDIFIED POTTASIUM MANGANATE SOLUTION
fe 3+ reduced to fe 2+ by IODIDE IONS
interconversion between cr 3+ and cr2o7 2-
cr 3+ in (cr(oh)6) 3- DARK GREEN) oxidisied to cro4 2- (YELLOW) by WARMING with HYDROGEN PEROXIDE solution in ALKALINE conditions
add dilute sulfuric acid to chromate solution—> orange dichromate solution (cro4(2-) + 2h(+) –> cr2o7 (2-) + h2o
cr2o7(-) (orange) REDUCED to cr (3+) by ACIDIFIED zince
reduction of cu 2+ and disproportionation of cu+
cu(2+) (pale blue) reduced to white CUI precipitate by IODIDE IONS .(2cu (2+) + 4I- —> 2cui + i2
NOTE: precips are ALWAYS SOLid
cu+ is unstable and disporportionates to cu and cu 2+
2cu + (aq)—> cu (s) + cu (2+)
test for co3 2-
add nitric acid , bubble gas released through limwewater, cloudy in presence of co2
test for so4 2-
add barium nitrate or baroium chloride, white precip formes ( baso4)
test for nh4+
cold naoh to compound and warm. hold damp red litmus paper over, red litmus–> blue `
transition metals as catalysts
fe- haber process
v2o5- contact process ( 2so2(g) + o2 reversible sign 2o3)
NOTE : HABER AND CONTACT ARE REVERSIBLE REACTIONS
hydrogenation o vegetable fats- nickle catalyst
decomposition of hydrogen peroxide to water and oxygen- mno2 catalyst (manganese V) oxide)
reaction of zinc with acids- cu2+ catalysts
pyramidal bond angle
107 (1 lone pair, and 3 ligands)
non linear bond anglw
104.5 ( two lone pairs and 2 ligands
trigonal planar
120
otctahedral
90
ammonium ion shape
tetrahedral- 109.5
co3 2- ion shape
trigonal planar (120)
no3 - ion shape
trigonal planar (120)
so4 2- ion shape
tetrahedral (109.5)
s
formation of idnuced dipols
movemment of e- produces changong dipole ,and instantaneous dipole is made, this induces dipole on neighbouring molecule, induced dipole induces more dipoles on neighbouring molecuels
how does something dissolve
intermolecular forces between the water and the lattice is stronger than intermolecular forces within the lattice so intermolecular forces between lattice break
polar substance have polar bonds (eg oh) so they dissolve In polar substances. cant dissolve in non polar as the intermolecular forces within lattice are too strong.
ONLY SIMPLE MOLECULAR SUBSTANCES ARE SOLUBLE (EG H20, H2 , CO2 , NE )
why water has high bp
hydrogen bonds , lots of energy needed
water high surface tension and viscosity
insects can walk
factors affectiing ionisation energy
atomic radius, nuclear charge, electron shielding ( inner electron repel outer)
ionisation energy acros period
increased nuclear charge, same shell= similar shielding, nuclear attraction incerease, atomic radius decrease, first ionisation energy increases
berylium and boron
2p subshell filling . 2p in boron has higher energy than 2 in beryllium o 2p easier to remove than 2s
nitrogen and oxygen
oxyen has 1 pair of electrons in 2p subshell, repulion= easier to remove
giant covalent lattice
non soluble in solvents
fall in melting points across period 3 at group 15
giant structures to simple
group 2oxides + water
oh- ions released (cao +h2o–> ca 2+ + 2oh-) alkaline SOLUTION FORMED
.group 2 hydoxides only slightly soluble in water , saturation causes precipitate.
group 2 hydroxides and water
precipitate forms, ca 2+ + oh- –> ca(oh)2 (s)
bromine, iodine, chlorine
orange, purple , pale green (dissolve in cyclohexane as its easier to see )
outer shell of halogens
s2p5
cl2 + h2o
hclo + hcl
cl2 + 2Naoh
naclo + nacl + h2o (naclo is bleach)
agx
SOLID
Carbonate + acid
co2 in LIMEWATER
Sequence of halide tests
carbonate, sulfate, halide
carbonate ions present in halide tet; ag2 co3
sulfate; ag2so4 precipitate
test for a mixture of ion
carbonate test, see bubbles, continue adding dilute nitrc acid until bubbling tops , all carbonate ions removed, move to next test (use nitric acid as sulfuric acid and hcl contain sulfate and cl- which interfere )
.sulfate test: to soluton left, add excesss ba (no3)3 , barium suflate precip formes, filter and remove
halide test: to solution left from sulfate test, ad silver nitrate , carbonate nad sulfate ions revmoved so no wrong precip fomred,
,add nh3 to confirm halide ( differentiate colours )
enthaloy change of reaction
enthalpy change that accompanies reaction in olar qiuantities shown in chemical equation under standard conditions
enthalpy of combustion
enthalpy change takes place when 1 mol of substance reacts COMPLETELY with oxygen UNDER STANDARD CONDITIONS
nthapy of foormation balancing
balance so that ONE MOLE of product present
enthalpy of neutralisation
energy change that accompanies reaction of acid by base to form ONE MOLE of water under standard conditions
accuracy of experimental value of combustion
heat loss
to surroundings
.incomplete meth combustion, evaporation of meth from wick
. non standard condition
average bond enthalpy
energy required to break of bonds in a gaseous molecule
altering rate of reaction by
changing surface area of solid reactants
catalyst
not used up in chemical reaction , forms intermediate, regenerated
heterogenous catalysts
differnet physical state, adsorbed, solids, work b adsorption and desorption
catalysts, sustainability and economic importance
indrease rate of reactions by lowring activation energy
.decreases temp needed
.less electricity or fossil fuel used
.allows operating processes with high atom economies and fewer pollutants
boltzmann
orgin, end doesnt meet x axis as no max energy, area under curve remains same as no of molecules is same .
use “ molecules” NOT “particles !”
catalyst in boltzmann
reduces ea but DONT draw two curves
explanation of dynamic equillibrium
exists
in a closed system when the rate of the forward
reacton is equal to the rate of the reverse
reacton and the concentratons of reactants and
products do not change
investigating eq with concentration
(yellow) 2cro4 (2-) + 2H+ (reversible sign) cr2o72- + h2 (orange)
add acid- eq shifts right
add base, eq shifts left, yellow colour
(SAME AS ACID BASE EQUILLIBRIUM !!)
Investigating eq with temp
. dissolve cobalt chlriide in water ,add hcl , plaec in iced water, pink colour
.set up boiling awter, add the boiling tube , solution = blue colour
. put solution back, solution= pink colour
(reaction is co(h2o)6 complex wiht 4 cl-, cocl4 2- is blue!)
kc of 1, less than 1, more than 1
eq , more than 1, eqi shifted to produces, eq less than 1 eq shift to reactants
increasing temperature
increases the rate constant
pv= nrt UNITS
Pressure=pa , volume= M3 , ideal gas constant = 8.32 jmol-1 k-1, temperature is in KELVIN, amount of gas is in MOLES
percentage yield is in… and atom economy in…
moles, molar mass of product/ reactamts
rate constant
derived from GRADIENT of a rate/ concentration graph
balancing equations for enthalpy of formation
make sure that it FORMS ONE MOLE
note: metals are in solid state !!!!!!!!!!!!!!!!!!!
enthalpy of formation of element
formation of one mole of element from its element
standard enthalpy of reaction, formation, combustion and neutralisation
. enthalpy change that accompanies a reaction in molar quantitites shown in a chemical equation under standard condition with all reatants and products in standard states
.enthalpy change takes palce when 1 mole of compound is formed from its elements udner standard conditions with all reactants and products in standard tates
..enhtalpy change that takes place when one mole of substance react completely with oxygen under standard condition with all reactants and products in standard states
.enthalpy chnage that ACCOMPANIES reaction of acid by base to form one mple pf h2o under standard condtitions with all reactants and prdoucts n standard states
advantages and disadvantages of fuel cells
advantages:
only H2O formed/ non-polluting
greater efficiency (1) EMPHASIS ON GREATER EFFICIENCY
disadvantages:
H2 difficult to store (1)
H2 difficult to manufactured initially /
limited life cycle of H2 adsorber/absorber
homogenous equillibria
include h2o
DO NOT INCLUDE IN HETERO!
