[PROMISE]

suppose a react CH4+O2 ,in exam a question came what's the reactant of CH4 (methane) + O2 ?how I will know that CO2 (carbon dioxide) + H2O (water) will be the product?

I mean to say that "how can I figure out the product or reactant by seeing reactant or product as clue?"


my post follows this rule- whenever asking questions show you have already tried to solve them on your own,

[Hunter2]

Some things have to be learned like others in the live.  In your given example methane will be combusted and water and carbon dioxide is the result. In other cases you can only find out in experiments and the results have to be remembered.

[PROMISE]

Some things have to be learned like others in the live.  In your given example methane will be combusted and water and carbon dioxide is the result. In other cases you can only find out in experiments and the results have to be remembered.

sir,didn't understand that- have to learn live ,did u mean I have to learn in online ,chat?

[Hunter2]

No I mean , if you have a component A and a Component B you never can know what will be the result. You have to learn it, like you learn vocabulary of a language.
In your case Methane and Oxygen will give Carbon dioxide and water during combustion.

But under special catalytic condition you also can produce methanol, formaldehyde or methanoic acid with it.

[PROMISE]

No I mean , if you have a component A and a Component B you never can know what will be the result. You have to learn it, like you learn vocabulary of a language.
In your case Methane and Oxygen will give Carbon dioxide and water during combustion.

But under special catalytic condition you also can produce methanol, formaldehyde or methanoic acid with it.

thanks,sir.I have understood,now .I have to take idea by doing some equations and rest of the things will be like Math.

[Arkcon]

thanks,sir.I have understood,now .I have to take idea by doing some equations and rest of the things will be like Math.

Let me tell you a problem you seem to be facing.  You believe that chemical equations will follow mathematical rules.  This is not true.  You will only confuse yourself if you continue to try to visualize the reactions in this way.  Briefly, you will have to memorize chemical reactions, especially the simplest ones.

Its hard to know what more help to give you, but lets try anyway.  You have methane, natural gas, a fuel used worldwide for heating and cooking.  You perform a chemical reaction with diatomic oxygen gas ... Aw, screw that technical explanation, you burn it. What do you get?  What will you expect to get?  What could you possibly get?  C₆H₈?  That's a component of gasoline, do we get gasoline when we burn natural gas? Do you expect HCCOOCHO?  I just made up string of atoms there, such a molecule may not even exist. 

[Enthalpy]

If you burn a hydrocarbon in pure oxygen you'll get more CO than CO₂ because the flame is so hot. So, there's nothing automatic. CO₂ is in air, where nitrogen dilutes the flame and cools it.