mass
amount
molar mass
concentration
solution volume
gas volume
molar gas volume
Avogadro
constant, L
number of
entities, N
CALCULATING ON THE SIDE OF SUCCESS – Module N(2027): STOICHIOMETRY WITH SOLUTION CONCENTRATIONS
N. STOICHIOMETRY IN AQUEOUS SOLUTION
N1. ESTABLISHING THE STOICHIOMETRIC FACTOR
N1.1 RECAP: WRITING AMOUNT-AMOUNT RATIOS ALGEBRAICALLY
Sections N1.1 - 1.3 allow a recap of the material encountered in H3.1 - 3.3 or/& M1.1 - 1.3, with the focus here on reactions in solution. The examples which follow will help to reinforce key ideas about amount-amount ratios and the interpretation of stoichiometric coefficients.
Should this recap not be required, and you are happy with Avogadro's postulate, then solution stoichiometry problems with concentrations begin with the fully worked example at section N2.
Note that ‘amounts ratio’ is incorrectly referred to by many as ‘molar ratio’ or ‘mole ratio’.
N1.2 RECAP: SETTING UP AMOUNT–AMOUNT RATIOS & MANIPULATING THEM
Amount-amount ratios assume a place of central importance in solving stoichiometry problems since they generate the required stoichiometric factor. As you have seen, the sources for these ratios are the coefficients (or stoichiometric coefficients) of a chemical equation,
i.e., the ‘large-font’ numbers immediately preceding written formulae.
In the teaching, understanding, and learning of such an important sub-topic, the stoichiometric factor is a crucial item which generally receives too little attention, and - not uncommonly - confusion ensues from here.
A multi-part worked example now follows.
There now follow some problems dealing with these key ideas about amounts ratios and the interpretation of stoichiometric coefficients allowing us to generate a stoichiometric factor.