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18 Cards in this Set
- Front
- Back
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Name the types of catalysis carried out by iron (III) ions reacting with I (aq) and S2O82- (aq) ions |
- Homogeneous as catalyst and reactants are in same state |
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Explain how transition metal ions such as Cu2+ are able to increase the rate of redox reaction |
- Transition metal ion reacts to form an intermediate compound - Oxidation states of the transition metal ion changes or metal ion changes - New ion/intermediate then reacts to reform the original transitional metal ion - Form original metal ion - activation enthalpy for this reaction is lower than without the metal ion |
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Copper has electron configuration of [Ar]3d10 4S1 and Cu 2+ has configuration [Ar]3d9. How does this provide evidence that copper is a transition metal? |
- Cu forms an ion with incompletely filled d-subshell |
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The reaction of Fe3+ ion in solution with excess hydroxide ions produce a red-brown solid. Give the ionic equation for the formation of its red-brown solid |
- Fe3+ (aq) 3OH- ----> Fe(OH)3(s) |
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The reaction of iron(11) ethanoate in solution of excess hydroxide ions produce a green precipitate. Give the ionic equation for the formation of this red-brown solid |
- Fe2+ (aq) + 2OH-(aq) ---> Fe(OH)2(s) |
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The green precipitate (iron(11) hydroxide) is left to stand for some time and the precipitate turns red-brown Name the red brown precipitate and explain what caused it to be formed? |
- Red-brown ppt is iron(III) hydroxide - Fe(OH)2 ions are oxidised - by oxygen |
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Fe3+ has electron configuration [Ar]3d5 and Fe2+ has configuration [Ar]3d6. How does this explain that Fe3+ ions are more stable than Fe2+ ions? |
- Half-filled d-sub-shell more stable - 3d5 configuration |
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When the rate of reaction with respect to substance X is being investigated the other reagents are used in large excess, Why is this done? |
- During the reaction only the concentration of 'Substance X' would be effectively changing or the concentration of the other reagents would be effectively constant |
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In a rates experiment the rates of reaction were measured when the amounts of reactants used up were small in comparison to the total quantities of reactants present, Explain why it is necessary to do this |
- As reactants are used up their concentration changes, the rate will change - Rate measured will be for initial concentration |
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Describe and explain the difference between heating under reflux and distillation |
- In heating under reflux - the condenser is vertical - in distillation - the condenser is sloped upwards at the side |
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Explain in terms of intermolecular bonds, the difference in the boiling points of propene CH=CH-CH3 and propanone CH3COCH3 |
- intermolecular bonds in propene are instantaneous(dipole)-Induced dipole - Intermolecular bonds in propanone are permanent dipole-permanent dipole - Higher temperature for propanone required because intermolecular bonds in propanone are stronger |
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Suggest two possible reasons why thalidomide may have been used as a sedative in place of drugs that existed at that time |
- More reactive - Smaller dose required - Fewer side effects |
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Suggest one way that the testing of drugs today ensures that the tragedy caused by the use of thalidomide by pregnant women is unlikely happen again |
- Safety test on drugs during pregnancy - test to see if drug can pass through the placenta - testing on pregnant animals |
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Give two successful outcomes of clinical trials that would be necessary before resveratrol could be marketed as an effective drug |
- no harmful side effects - it works better than standard medicine |
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Give three questions that clinical trails are designed to answer |
- Is the drug safe to be used on humans? - Does it do the job it is designed to? - Is it better than the standard treatment being used? |
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Describe how a student would carry out recrystailization of a solid containing both soluble and insoluble properties |
- Heat (the impure) sample with solvent, use hot solvent - With a minimum amount of solvent - filter - leave filtrate to crystallise - filter off crystals , wash and dry - after crystallization soluble impurities stay in solution |
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What properties should a solvent have to achieve efficient re-crystallisation |
- Solvent should dissolve solute at a higher temperature - Solvent dissolve but solute should be much less soluble in room temperature |
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In what respect are addition reactions environmentally friendly? |
- Few atoms wasted/ high (100%) atom economy |
