How are stoichiometry and molarity related?

Question

Wyatt Atkins · Accepted Answer

Well, stoichiometry requires EQUIVALENCE with respect to mass and charge....

And for an older treatment of the principles involved, see this old answer. And the fundamental principle of stoichiometry is #"garbage in equals garbage out"#. Every chemical reaction must be balanced with respect to mass and charge. A #10*g# mass of reactants from all sources yields at most a #10*g# mass of products. #"Molarity"# is a concentration term, i.e. #"molarity"="moles of solute"/"volume of solution"#...and as such it has the units of #mol*L^-1#.. And so if we have TWO of the three quantities, say #"molarity"# and #"volume"#, we can get the third..#"moles of solute"#... …#"molarity"xx"volume"="moles"#....and this is certainly consistent dimensionally. What do I mean by this? And a practical example? Well suppose I gots a #100*mL# volume of #HCl(aq)#, that is #1*mol*L^-1# with respect to #HCl#. What mass of sodium hydroxide is required for equivalence? We write out the stoichiometric equation as a preliminary: #HCl(aq) + NaOH(aq)rarr NaCl(aq) +H_2O(l)# #n_"HCl"=0.100*Lxx1*mol*L^-1=0.100*mol# And for equivalence we require equimolar sodium hydroxide... #0.100*molxxunderbrace(40.0*g*mol^-1)_"molar mass of NaOH"=4.00*g#...i.e. a #4*g# mass of hydroxide is required for equivalence.

Cameron Andrews · Answer

undefined Stoichiometry is the study of the quantitative relationships between reactants and products in chemical reactions. Molarity, on the other hand, is a measure of the concentration of a solute in a solution, expressed as the number of moles of solute per liter of solution. In stoichiometry, molarity is often used to determine the amounts of reactants and products in a chemical reaction based on their balanced stoichiometric coefficients. Molarity provides the information needed to convert between the volume of a solution and the number of moles of solute, which is essential for stoichiometric calculations.