doesnt oxygen burn also?

[sangria1986]

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in one of the aamc tests the question asked which gas would burn or something like that....i ruled it down to oxygen or hydrogen gas...i thought oxygen burned so i picked that. apparantly its H2 that burns as well...i thought o2 did too. isnt that what combustion means?

CnH2n + 02-> Co2 H2o

 

[Rabolisk]

This combustion means the hydrocarbon burns in presence of oxygen. Was this AAMC 5 or 7?

 

[sangria1986]

This combustion means the hydrocarbon burns in presence of oxygen. Was this AAMC 5 or 7?

dont remember...but the question was from a passage where it said that a flammable gas was evolved. I thought it was oxygen. hydrogen was the other choice

 

[phltz]

When we talk about something burning, we usually mean that it reacts with O2 gas, generally forming CO2, H2O, etc. Although oxygen is involved in this process, we don't generally don't say that oxygen itself burns, only the other substance.

 

[Rabolisk]

Was this from an electrochemistry passage? I think I know what you're talking about. When a gas is "evolved" that means it is the product of a reaction. If you find the exact question, I should be able to answer it in detail.

 

[sangria1986]

Was this from an electrochemistry passage? I think I know what you're talking about. When a gas is "evolved" that means it is the product of a reaction. If you find the exact question, I should be able to answer it in detail.

i know evolve means its a product but I wasnt sure how to tell that the answer would be H2....the book answer says that because the passage stated the gas evolved burned it must have been H2.

My real question is...what other unique trends do I need to know? I know the alkali metals react with water violently, but how about alkaline earth metals? I know they can act as bases. I know that the halogens react quickly too to reach octet and I know nobel gasses are inert. But I dont know anything else and Im not sure what else I need to know.

 

[Rabolisk]

If you can find the passage and the question, I can help you out.

 

[sangria1986]

If you can find the passage and the question, I can help you out.

its not worth it...it'll take forever to find it anyway. I'm just memorizing some specific trends I come across