Solution Chemistry involves combining the concepts of molarity and stoichiometry.
Concept #1: Under solution chemistry our given information may be in units of mass, volume or molarity.
Stoichiometry is used when given the known quantity of one compound and asked to find the unknown quantity of another compound or element. Now we throw molarity into the mix.
Concept #2: When dealing with solution chemistry we use a new adjusted stoichiometric chart.
This new Stoichiometric Chart is used anytime we are given the known quantity of a compound in units such as mL, L or M and asked to find the unknown quantity of another compound.
Example #1: Molarity and Stoichiometry Calculation
By using our new Stoichiometric Chart we can now answer stoichiometric questions dealing with molarity.
Using our new Stoichiometric Chart it is possible to now calculate the unknown volume of a compound through molarity.
Practice: How many milliliters of 0.325 M HCl are needed to react with 16.2 g of magnesium metal?
2 HCl (aq) + Mg (s) ----> MgCl2 (aq) + H2 (g)
Knowing the volume and molarity of a compound allows us to determine the molarity of an unknown compound.
Practice: What is the molarity of a hydrobromic acid solution if it takes 34.12 mL of HBr to completely neutralize 82.56 mL of 0.156 M Ca(OH)2?
2 HBr (aq) + Ca(OH)2 (aq) ----> CaBr2 (aq) + 2 H2O (l)
Practice: Iron (III) can be oxidized by an acidic K2Cr2O7 solution according to the net ionic equation: Cr2O72- + 6 Fe2+ + 14 H+ -----> 2 Cr3+ + 6 Fe3+ + 7 H2O.
If it takes 30.0 mL of 0.100 M K2Cr2O7 to titrate a 25 mL Fe2+ solution, what is the molar concentration of Fe2+?