Making sense out of Chemical Reactions
Wait! Don't throw this away in disgust! It really is possible to do it! Read,
think and learn:
We have arbitrarily (and conveniently) divided inorganic chemical reactions
into THREE large categories. The bottom line is that you need to learn how to
recognize, write and/or complete, and balance these reactions. They are the "stuff" of
which chemistry is made.
How to recognize: the ones you will see in this course involve
TWO compounds as possible reactants.
e.g. sodium sulfate + barium chloride → ??????
Na2SO4 + BaCl2 → ??????
is possibly a precipitation reaction.
iron + hydrochloric acid → ????????
Fe + HCl → ?????????
is definitely not.
How to complete: try switching the ions and check products against the solubility
rules; if at least one product is insoluble, you have a reaction;
if both possible products are soluble, you have a dud (i.e., no
e.g. Na2SO4 + BaCl2 → NaCl + BaSO4 (not balanced!!!)
according to the solubility rules, BaSO4 is insoluble. So there is a reaction.
NaNO3 + BaCl2 → Ba(NO3)2 + NaCl (not balanced!!!)
according to the solubility rules, both possible products are soluble. NO
reaction will occur. Such a problem is best written (in molecular form) as:
NaNO3 + BaCl2 → N.R.
How to balance: make sure you have the correct formulas first by checking the
charges of the ions. Then AND ONLY THEN use coefficients in
front of the formulas to get the same number of atoms on both
sides. DO NOT ALTER FORMULAS TO FORCE A
REACTION TO BALANCE.
e.g. Na2SO4 + BaCl2 →