How are chemical equations formed?

1 Answer
Jul 26, 2017

Answer:

#"Garbage in equals garbage out"#.

Explanation:

Every chemical reaction that has ever been performed observes 2 principles.

#(i)# #"Conservation of mass."#

#(ii)# #"Conservation of charge."#

What do these mean? Well for #(i)# it means that if I start with a #10*g# mass of reactants, from all sources, AT MOST I can get a #10*g# mass of products. In practice I am not even going to get that. Losses invariably occur on handling, and side reactions may occur, both of which will detract from the overall yield.

And so if we encounter an equation like the following,

#CH_4(g) + O_2(g) rarr CO_2(g) +H_2O(l) + Delta#

We can immediately reject it out of hand, because there is NO MASS balance between reactants and products.

On the other hand, for....

#CH_4(g) + 2O_2(g) rarr CO_2(g) +2H_2O(l) + Delta#

There is MASS BALANCE between reactants, and products, and we may also QUANTITATIVELY assess the amount of heat produced, #Delta#, per gram or per mole of the hydrocarbon combusted. And thus this reaction is a reasonable representation of reality.

And conservation of charge follows the same principle, but is most strongly apparent for redox reactions, where we conceive of the electron as a virtual particle, that exchanges between atoms in redox reactions.

Both of these principles underly stoichiometry, which is fancy word for saying #"garbage in equals garbage out"#. Stoichiometry applies always in chemical reactions. More prosaically it also applies in the banking and finance industry......

#"for every credit item, there must be a corresponding debit item."#

I argue that this is an excellent example of #"stoichiometry"#. What does this mean in the context I give?

Do you see from where I am coming? Anyway, you have asked a rather open-ended question. If we are barking up the wrong tree, come again.