Past Papers Flashcards
What many elements bind to a octahedral complex ion
6
How many bonds does a bidentate ligand has
2
What technique does purify and identify a compound
Distillation
The absorption of radiation in the radio frequency region causes H nuclei to adopt a high frequency state aligned against a strong magnetic field.
Explain how this leads to peaks in an NMR spectrum corresponding to the different H environments
Hydrogen nuclei flip with magnetic field
Different wavelengths
OR
Different energy gaps between high and low states
State a reason why different bonds absorb different wave numbers of infrared radiation
Different strengths of bonds
State what is meant by a weak acid
Partially disassociated into ions in an aqueous solution
The sodium salt of Heuke acid formed a new reaction mixture during the first step is treated with dilute hydrochloric acid. A white precipitate of puke acid is formed.
Explain why adding hydrogen ions in the salt of the weak acid results in the formation of undisassociated weak acid molecules
Hydrogen ions react with the conjugate base
What causes d orbital splitting in octahedral complex 
Repulsion from Electrons
State the aufbau principal
Electrons fill orbitals in order of increasing energy
State one difference between bonding molecular orbital and an anti-bonding molecular orbital 
Anti-bonding high energy or anti-bonding unfilled and bonding filled 
Explain why cis and trans isomerism can exist in some compounds with carbon to carbon double bonds 
Lack of rotation at the double bond
Two different groups attached to each carbon atom
Describe fully how weighing by difference Work
Weigh the empty container
weigh the container with the sample 
State what is meant by nucleophilic
Negatively charged ions or neutral molecules that are electron rich
What is meant by an antagonist?
Binds to receptor and prevents the response
Sate second law of thermodynamics
The entropy of a reaction system and its surroundings increases for a spontaneous process
Explain how a pi bond is formed
Orbitals overlap side on
Colour arises in some aromatic compounds due to absorption of visible light .
Explain why the conjugated system in benzene result in absorption of ultraviolet light and not visible light.
The energy gap is too large between the from HOMO to LUMO since the conjugated system is small
The concentration of cobalt ions in a cobalt chloride solution can be determined by complexometric titration
Suggest a suitable complexometric reagent that could be used in this titration
EDTA
What solvent is used in a haloalkane to alkene
Ethanol
Explain why the pH of a buffer solution remains approximately constant when small volume of water is added
Ratio of acid and salt unchanged/ the salt and acid re diluted by the same quantity
Describe an experiment procedure that could be carried out to determine which of the two solutions has the larger buffer capacity
Same volume of each buffer
Measure pH after same volume of alkali added
Define the term drug
Substance which alters the biochemical body processes
The impure precipitate of benzoic acid is produced by acidifying the alkaline sodium benzoate
Explain fully why an aqueous solution of sodium benzoate is alkaline
Ions from the salt react with H+ ions from water, this results in excess OH- ions from water equilibrium
What is the definition of a bronsted Lowrydefination for a base
Proton acceptor
Explain fully why a solution of complex ion Zn(H2O)6^2+ is colourless
Full 3d subshell
No absorption of visible light
Explain the effect infrared radiation has on the bonds within molecules and how this allows different functional groups to be identified
Vibrate
Different bonds/functional groups absorb different wave number/wavelength/frequency/energy 
