Past Papers

Question 1

What many elements bind to a octahedral complex ion

Answer 1

6

Question 2

How many bonds does a bidentate ligand has

Answer 2

2

Question 3

What technique does purify and identify a compound

Answer 3

Distillation

Question 4

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

Answer 4

Hydrogen nuclei flip with magnetic field
Different wavelengths
OR
Different energy gaps between high and low states

Question 5

State a reason why different bonds absorb different wave numbers of infrared radiation

Answer 5

Different strengths of bonds

Question 6

State what is meant by a weak acid

Answer 6

Partially disassociated into ions in an aqueous solution

Question 7

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

Answer 7

Hydrogen ions react with the conjugate base

Question 8

What causes d orbital splitting in octahedral complex 

Answer 8

Repulsion from Electrons

Question 9

State the aufbau principal

Answer 9

Electrons fill orbitals in order of increasing energy

Question 10

State one difference between bonding molecular orbital and an anti-bonding molecular orbital 

Answer 10

Anti-bonding high energy or anti-bonding unfilled and bonding filled 

Question 11

Explain why cis and trans isomerism can exist in some compounds with carbon to carbon double bonds 

Answer 11

Lack of rotation at the double bond
Two different groups attached to each carbon atom

Question 12

Describe fully how weighing by difference Work

Answer 12

Weigh the empty container
weigh the container with the sample 

Question 13

State what is meant by nucleophilic

Answer 13

Negatively charged ions or neutral molecules that are electron rich

Question 14

What is meant by an antagonist?

Answer 14

Binds to receptor and prevents the response

Question 15

Sate second law of thermodynamics

Answer 15

The entropy of a reaction system and its surroundings increases for a spontaneous process

Question 16

Explain how a pi bond is formed

Answer 16

Orbitals overlap side on

Question 17

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.

Answer 17

The energy gap is too large between the from HOMO to LUMO since the conjugated system is small

Question 18

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

Answer 18

EDTA

Question 19

What solvent is used in a haloalkane to alkene

Answer 19

Ethanol

Question 20

Explain why the pH of a buffer solution remains approximately constant when small volume of water is added

Answer 20

Ratio of acid and salt unchanged/ the salt and acid re diluted by the same quantity

Question 21

Describe an experiment procedure that could be carried out to determine which of the two solutions has the larger buffer capacity

Answer 21

Same volume of each buffer

Measure pH after same volume of alkali added

Question 22

Define the term drug

Answer 22

Substance which alters the biochemical body processes

Question 23

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

Answer 23

Ions from the salt react with H+ ions from water, this results in excess OH- ions from water equilibrium

Question 24

What is the definition of a bronsted Lowrydefination for a base

Answer 24

Proton acceptor

Question 25

Explain fully why a solution of complex ion Zn(H2O)6^2+ is colourless

Answer 25

Full 3d subshell
No absorption of visible light

Question 26

Explain the effect infrared radiation has on the bonds within molecules and how this allows different functional groups to be identified

Answer 26

Vibrate
Different bonds/functional groups absorb different wave number/wavelength/frequency/energy