Question

A scientist measures the rate of a reaction between two liquids. Then he performs the reaction again, adding solid manganese. The reaction takes place more quickly the second time. The mass of the manganese decreased by 0.45 grams during the reaction. He claims that the manganese acted as a catalyst because it sped up the reaction. Explain what is wrong with the scientists' reasoning.

I am not so sure...

Answer 1

catalysts aren't comsumed

Answer 2

so would this be a good answer?
A catalyst is something that aids/speeds a reaction but is itself unchanged. If manganese was consumed during the reaction it was obviously chemically changed, probably by reacting with one or both liquids.

Answer 3

sounds good dude

Answer 4

I am a girl... but thanks ! (:

Answer 5

haha sorry, no prob !

Answer 6

no actually many theories have been put up regarding the action of catalyst...
you can simply take it this way that..
a catalyst forms ""temporary bonds"" with one of the reactants to give an intermediate product...which is short lived as this product further reacts with the other reactant to give the required product...take it like
suppose initially..A+B---AB...(RATE SLOW)
NOW A+ C(catlst)--AC
&AC +B-------AB+C....(overall rate fast)
and this C is available again for the remaining reactants to give products the same way..
thus "the catalyst remains chemically unchanged after the reaction is over..it only provides a faster way to reach the products"
and so if the mass of Mn is reduced,it is not acting as a catalyst...as permanent products might have been formed which couldnt bring back Mn into its previous state...and so its just aiding the reaction and not catalysing it..
hope you got it...

Answer 7

manganese was the promoter of the reaction

Answer 8

well promoters are added along the catalyst...here you can say that by some other mechanism..we coincidntly got the initial products along with some products of Mn,,,and it made the rctn fAST...i think so...whats you say???