[svarc]

Hello there. I am new on this forum.
I have one question that bothers me long time and i cant find anyone to answer me that question so here i am asking it here. Btw i searched the forum for such topic but i couldn't find any maybe i am blind and didn't see it or there is really no topics like this. Anyway pls let me know if there is such answer or lead me to some info.
So i want to know how can i predict (using basic chemistry like oxidation state or something like that) what products will i get in a reaction? I have found info about reaction with only 2 chemicals and that info only confused me more.
For example how can i predict the products of 3 chemicals in reaction like KNO3+C+S? I know the whole equation and the balancing stuff but i dint know how to explain why those products occur and others not.
KNO3+C+S=>K2S+N2+CO2 this is the unbalanced equation. So i want to know in calculated way with some info of the element to be able to answer why potassium reacts with sulfur rather than with oxygen to form K2O instead of K2S or why nitrogen molecule is product instead nitrogen oxide?
Thanks in advance and best wishes to all.

[enahs]

It is not simple. It is in fact very complicated and depends on many things and varies from reaction to reaction.
So, in short, your answer is "Chemistry".

[svarc]

Hm i though that it will be complicated tho.  But can anyone explain how it is done at least the steps that are taken to get to the results? Or any info site about this subject just to get some information from?
Thanks for the replay enahs.

[bessieboy521]

One way to predict reaction with some luck is to look at the relative stabilities and heat of formation to make each product. You could draw a big table comparing value, but often times some obvious product will be noticed, for instance, N2 vs. O2 The stability of N2 alone explains that one. I could be wrong, however, the crudest estimate would probably start with thermodynamics. Also, it is not completely unlikely that other products will not form as intermediates, or rather small amounts, but then you have to consider the whole reaction again to decide whether they will continue to react. 'IN GENERAL' reactions only take place if the product is relatively more stable than the reactants, or if the number of moles is increased by reacting (entropy and enthalpy) This is one reason why (we) as chemists use burners and hot plates. The added heat allows us to push reactions in an energetically unfavorable direction.

[svarc]

Thanks bessieboy for trying to explain me. You pointed me the right way it seems like i need to learn more to be able to do the task that i want to know how to do.
Thanks to everyone anyway.

[ajkoer]

OK, I think the best way to answer this question is to 1st closely observe what gases are formed (H2O vapor, SO2 and CO2) and what is the composition of the residue material (KNO2, K2CO3 and/or K2SO3, and I doubt K2S).

If mainly KNO2, then adding HCl may generate some NO and NO2. Caution: Nitrogen Dioxide is a reddish-brown pungent and dangerously toxic gas.

If K2SO3, then HCl will liberate the corrosive Sulfur Dioxide (SO2) gas. If K2S, the gas is H2S( Hydrogen Sulfide is a particularly odorous and very toxic gas).

If K2CO3, a clear odorless heavy gas, carbon Dioxide (CO2) will be created with HCl.

Of, course, in combination the identification of the different gases becomes more difficult, but you can always react KNO3 + S and KNO3 + C separately for some insights. To make things even more complex, changing the mixture composition may not only change the amount of products, but also what is produced.  I would start working with the portions suggested as giving the best reaction for your purpose, find (per tests above) what is produced and attempt to balance the chemical equation to gain suggestions for possible improvement.

Good luck.