Inorganic Flashcards
Electronegativity
a measure of the ability of an atom in a molecule to attract the electrons of a shared pair to itself
Making Bleach
Cl2+2NaOH->NaCl+NaClO+H2O
disproportionation
(NaClO=chloric (I) acid=bleach)
Dynamic equilibrium
conc. of reactants and products are constant
rate of forward and backward reactions are the same
Rate Equation
rate=k([A]^n[B}^m)
&
k= ln2/half life
Exponential factor of Arrhenius
proportion of molecules that have sufficient energy for a reaction to take place
Pre-exponential term of Arrhenius
accounts for frequency of collisions with correct orientation
Arrhenius theory
Acids produce H+ in solution
Bases produce OH- in solution
Bronsted-Lowry theory
Acids donate a proton
Bases accept proton
Lewis theory
Acids accept lone pair
Bases donate lone pair
Relative atomic mass
The weighted mean mass of an atom of an element relative to one twelth of the mass of an atom of C12
Relative Isotopic Mass
the mass of an atom of an isotope compared to 1/12th of the mass of an atom of C12
Molecular formula
The number of atoms of each element in a compound
Empirical formula
The simplest whole number ratio of atoms of each element in a compound
Atom economy
calculated to limit waste products and make reactions more sustainable.
pH of weak acid
Ka = [H+][A-] / [HA]
therefore
ph= -log([H+])
Kw
Ionic product of water
Kw= [H+] [OH-}
Why H2O left out of equation?
Little H2O is ionised as POE lies to the left.
pH of strong base
[OH-] is conc. given
[H+]=Kw / OH-
ph= -log([H+])
How does Kw vary with temperature?
H2O ⇌ H3O+ + H+ endothermic reaction Temp increases; POE moves to right (fwd reaction favoured); [H+] & [OH-} increases; Kw increases overall, pH decreases
Define Buffer
solutions which minimises change in pH when small quantities of acid and alkali are added
Buffer solution made of:
1) Mix weak acid and it’s conjugate base (salt of acid) in equi-molar quantities
2) neautralise a weak acid with a strong base
weak acid in excess so some is unreacted
neautralise half the acid with a half-molar soluble base
Note:
[H+] = Ka
pH = pKa of the HA
Equivalence point
when the two solutions are mixed together in exactly equi-molar amounts (equation amounts)
Methyl Orange
used:
Strong acid v. Strong base
Strong acid v. weak acid
Phenolphthalein
used:
Strong acid v. Strong base
Weak acid v. Strong acid
Bromothymol blue
Used:
Strong acid v. Strong base
Conditions for electrodes
Standard conditions
298K
100 kPa
Concentration of ions 1 mol dm-3
KMnO4 redox titration colour change
Purple to colourless
K2Cr2O7 redox titration colour change
turns green
need redox indicator to see- violet-blue
Iodine/Thiosulphate redox titration colour
production of I2 = brown colour (ClO + KI)
end difficult to spot; add starch so turns Blue/black
endpoint- all blue/black disappears.
Periodicity
Elements that show a repeating pattern in chemical and physical properties.
Halogen displacement reactions
KBr (colours)
In aqueous soln. In organic soln.
w/Cl2 yellow (Br2) Orange (Br2)
KI (colours)
In aqueous soln. In organic soln.
w/Cl2 orange/brown (I2) Purple (I2)
w/Br2 orange/brown (I2) Purple (I2)
Test for Carbonates
ass dilute HCl
CO2 is released- bubble through limewater-> turns cloudy
Test for Sulfates
add dilute HCl then Barium chloride (BaCl2)
white ppt
Test or Halides
Add nitric acid then Silver nitrate
Cl= white ppt + dissolves in Dil. NH3 & conc. NH3
Br= cream ppt + dissolves in Dil. NH3
I= yellow ppt + doesn’t dissolve in NH3
Test for Ammonium Compounds
Add NaOH and warm mixture
If damp red litmus paper turns blue, NH3 is present
