segunda-feira, 21 de janeiro de 2013

Os Catalisadores

Os catalisadores são substâncias que numa reação química alteram a velocidade da reação, mas não se consomem. Os catalisadores não são reagentes. Os catalisadores alteram a velocidade mas no final desta reação a quantidade de catalisador é a mesma do que inicialmente.



Os catalizadores não actuam em qualquer reacção química. Por exemplo, a clorofila é o catalisador da reacção da fotossíntese, mas não catalisa outras reações.



Os catalisadores podem aumentar ou diminuir a velocidade de uma reacção química. Quando o efeito é reduzir a velocidade são chamados de inibidores ou catalizadores de acção negativa. Quando o efeito é aumentar a velocidade, são denominados catalisadores de acção positiva ou apenas de catalisadores.




Ex. Os conservantes são inibidores dos alimentos





6 comentários:

  1. .l. pensas que percebes de fisico-química mais que eu, sou o einstein!

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