Inorganic memory module 3 Flashcards
periodicity
The repeating trends in properties of the elements
First ionisation energy
The energy requires to remove one electron from ach atom of gaseous atoms of an elements to form one mole of gaseous 1+ ions.
What affects ionisation energy
- atomic radius
- electron sheildign
- nuclear charge
metallic bonding
The strong electrostatic attraction between a metal cation and a sea of delocalised electrons
disproportionation
a redox reaction in which the same element is both oxidised and reduced
e.g. Cl2(aq)+2NaOH(aq) –> NaClO(aq) + NaCl (aq) + H20(l)
Test for carbonates
- Add dilute nitric acid
- bubbles of C02 will be produced
- bubble through lime water to turn turn cloudy
CO3- + NO3- –> NO3- + C02 + H20
Test for sulfate
- add aqueous barium ions
- formation of white precipitate of barium sulfate
Ba2+ + SO4^2- –> BaSO4 (s)
Test for Halides
- Add aqueous silver nitrate to aqueous solution of halides
- form silver halide precipitations (white, cream and yellow)
- Add aqueous ammonia to test solubility
Ag+ + X- –> AgX (s)
chlorine - white, soluble in dilute NH3
Bromide - cream, soluble in concentrated NH3
Iodide - yellow, insoluble in concentrated NH3
Correct sequences of tests
- carbonate (no possibility of incorrect conclusions)
- sulfate (Carbonate with also produce what precipitate)
- halide (from silver carbonate and silver sulfate will not form precipitates)
Enthalpy
The measure of heat energy in a chemical system
calculation for enthalpy change
^H = H (Products) - H(reactants)
Standard cons
- 298 k
- 100 kPa
- 1.00 mol dm-3
The standard enthalpy change of reaction
^rH > the enthalpy change that accompanies a reaction in the molar quantities shown in the chemical equation under standard conditions, with all reactant and products in their standard conditions
The standard enthalpy change of formations
The enthalpy changes that takes place when one mole of a compound is formed from is constituent elements, under standard conditions, with all reactant and products in their standard conditions
The standard enthalpy change of combustion
The enthalpy change that accompanies the change that takes place when 1 mole of substance reacts completely with oxygen. Under standard conditions, with all reactant and products in their standard conditions