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Topic: Silane burns  (Read 2451 times)

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Offline linkamfai

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Silane burns
« on: May 23, 2015, 06:17:18 AM »
Why silane burns in contact with air, whereas methane requires a spark before it will combust ??? ???
« Last Edit: May 23, 2015, 07:09:38 AM by linkamfai »

Offline Borek

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Re: Silane burns
« Reply #1 on: May 23, 2015, 06:26:53 AM »
You have to show your attempts at solving the question to receive help. This is a forum policy.

Have you heard a term "activation energy"?
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Offline linkamfai

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Re: Silane burns
« Reply #2 on: May 23, 2015, 07:13:54 AM »
You have to show your attempts at solving the question to receive help. This is a forum policy.

Have you heard a term "activation energy"?

I'm sorry for against the policy.
Is that any reason(s), other than electronegative caused the different in activation energy?

Offline Corribus

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Re: Silane burns
« Reply #3 on: May 23, 2015, 10:59:39 AM »
Flammability and pyrophoricity are complex properties and often are affected by factors not directly related to the compound itself (impurities, etc.). But a simplistic explanation can be had by considering that the combustion of either silane or methane requires in some way breaking an Si-H or C-H bond, and the rate of the reaction will depend on how much energy it takes to do this. Si-H bond is significantly weaker than C-H bond (for the silane/methane reactions, I find the bond enthalpy to be ~ 335 kJ/mol and ~ 432 kJ/mol, respectively). Can you think of a plausible reason why?
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

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