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AQA Questions on catalysis, please help

1. Explain why in some commerical processes gaseous reactants are blown through powder coated with a solid catalyst.
2. Very small amounts on impurity in mixtures of reactants can drastically reduce catalytic activity. Give one example of this and explian why this happens- Is this do with poisioning?
jesus_navas
1. Explain why in some commerical processes gaseous reactants are blown through powder coated with a solid catalyst.
2. Very small amounts on impurity in mixtures of reactants can drastically reduce catalytic activity. Give one example of this and explian why this happens- Is this do with poisioning?


Are you studying chemistry as a back up in case your football career in Sevilla doesn't work out?

1. So that the catalyst occupies a very large surface area on which the reaction can occur.

2. yes it's to do with poisoning. eg V2O5 catalyst in the contact process may be poisoned by small quantities of heavy metals which bind to the catalyst surface in an irreversible manner.
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jesus_navas
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question 1 is a 4marker so can you give me a bit more depth.


p.s. lol hes my favourite player as im from spain.
Not really sure what they want.... but you could mention that powder has a very large surface area. That in heterogeneous catalysis the reacting molecules have to bind to the surface of the catalyst and this is where the reaction takes place. By blowing the gas through the powder the particles remain separated to keep the surfaces approachable and the gas can mix thoroughly with the catalyst and also the proucts are blown away to where you want them.

Fabian Ayala ... now there's a player.
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jesus_navas

2. Very small amounts on impurity in mixtures of reactants can drastically reduce catalytic activity. Give one example of this and explian why this happens- Is this do with poisioning?


Eg if leaded petrol is used, it can poison the car's catalytic converter by settling on it and stopping NO and CO molecules becoming adsorbed onto the surface because it will block the surface area. Thus it is rendered useless and becomes poisoned.
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jesus_navas
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cheers guys, rep tommorow, if any of you are bio whizz kids can you take a look in the bio section please. I am in need of help on respiration.
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haha no problem :wink:

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