CALCULATIONS......   Background and Overview

STOICHIOMETRY

Stoichiometry.... the quantitative understanding of how much of each reactant is used to form how much of each product.
The steps in a stochiometry problem are :
  1. Write a Balanced Equation.
  2. Determine the the known moles of reactants used or products formed.
    • Pure Solid ........ mole = (mass)/(molecular weight)
    • Impure Solid..... mole = (mass)(purity)/(molecular weight)
    • Solution............ mole = (volume)(Molarity)
  3. Determine the Limiting Reagent.
  4. Calculate the desired quantity.

mass in g; volume in L; purity in per cent/100)
redline.gif (117 bytes)

...
Manipulating the DATA from this experiment requires an understanding of

Solution Stoichiometry.

Solution......... A homogeneous mixture of a solute in a solvent.
Molarity........ A measure of concentration; moles of solute per Liter of solution.

(Concentration) (Volume) = Total Amount
(mL)(M) = millimoles
(L)(M) = moles

DILUTION
  • amount solute present before dilution = amount solute present after dilution.
  • calculate total amount of solute added and divide by total volume of solution.
CONCENTRATION
  • Molarity... moles of solute per Liter -or- millimoles of solute per milliliter
  • weight/volume Per Cent... grams of solute per 100 mL (deciliter)
  • Parts per million ... grams of solute per one million grams of solution.
    For dilute aqueous solutions, this is approximately... mg of solute per Liter.

Application to this experiment............................ CONTINUE

RWK 1997