Chemistry 0.0 / 5 ? ChemistryMix- summary of some hard topicsA2/A-levelOCR Created by: TinaCreated on: 10-04-14 09:46 Hydrogen oxygen fuel cell H2 +2OH- = 2H20 +2e. 1/2o2 + 2H2O + 2E = 2OH-. therefore: H2 + 1/2O2 = H20 1 of 27 Colour change from Cu2+ to Cu(OH)2 Pale blue to pale blue 2 of 27 Colour change from Co2+ to Co(OH)2 Pink to blue 3 of 27 Colour change from Fe2+ to Fe(OH)2 Green to green 4 of 27 Colour change from Fe3+ to Fe(OH)3 Yellow to brown 5 of 27 Colour change from [Cu(H2O)]2+ + 4NH3 = [Cu(NH3)4(H2O)2]2+ + 4H2o Pale blue solution to dark blue solution 6 of 27 Colour change from [Cu(H2O)]2+ + 4Cl- = [CuCl4]2- + 6H2o Pale blue solution to yellow solution 7 of 27 Colour change from [Co(H2O)]2+ + 4Cl- = [CoCl4]2- + 6H2o Pink solution to blue solution 8 of 27 CDCl3 Deuterated solvent, gives no signal in NMR 9 of 27 TMS Standard for chemical shift measurements (1s = 0ppm) 10 of 27 D20 Exchange with protons in OH and NH = no peak 11 of 27 Chemical shift A scale comparing frequency of NMR adsorption with frequency of reference peak of TMS at s=0ppm 12 of 27 Si(CH3)4 Formula of standard reference compound in NMR. Responsible for 0 on NMR 13 of 27 How is Tollens reagent made? NaOH and silver nitrate = silver oxide + brown precip. NH3 added until precip dissolves 14 of 27 Halogen carrier Forms Cl+ 15 of 27 What if there is no molecular ion peak? Compound is too unstable 16 of 27 Base peak. Molecular ion peak Most abundant fragment. Peak by unfragmented peak. 17 of 27 Why triglycerides are soluble in non-polar solvents and not in water? Van der Waals between triglyceride's and non-polar. Triglycerides cant hydrogen bond. 18 of 27 Optical isomerism Mirror image, non-superimposable, rotates plane polarised light in opposite direction to same degree. 19 of 27 Cis/trans Ligand donates a lone pair of e. Complex accepts a lone pair of e. To make a dative covalent bond. 20 of 27 2nd IE of Ca2+ more endothermic than 1st of Ca+ Ca2+ ion smaller and greater attraction 21 of 27 2nd EA of O2 is + Energy required to overcome repulsion as O- are e are both negative 22 of 27 1st IE of Ca is endothermic Energy needed to overcome force of attraction between outer e and nucleus 23 of 27 1st EA of O2 is endothermic E attracted to nucleus 24 of 27 Protein and nylon 6,6 Protein: different R groups, higher melting point, longer chain length 25 of 27 MnO4- + 8H+ + 5Fe2+ = Mn2+ + 5Fe3+ + 4H2O Purple to pink 26 of 27 2Cu2+ + 4I- = 2Cu + I2 Makes a white precipitate and brown solution 27 of 27
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