Ch.1 - Chemical MeasurementsWorksheetSee all chapters
All Chapters
Ch.1 - Chemical Measurements
Ch.2 - Tools of the Trade
Ch.3 - Experimental Error
Ch.4 + 5 - Statistics, Quality Assurance and Calibration Methods
Ch.6 - Chemical Equilibrium
Ch.7 - Activity and the Systematic Treatment of Equilibrium
Ch.8 - Monoprotic Acid-Base Equilibria
Ch.9 - Polyprotic Acid-Base Equilibria
Ch.10 - Acid-Base Titrations
Ch.11 - EDTA Titrations
Ch.12 - Advanced Topics in Equilibrium
Ch.13 - Fundamentals of Electrochemistry
Ch.14 - Electrodes and Potentiometry
Ch.15 - Redox Titrations
Ch.16 - Electroanalytical Techniques
Ch.17 - Fundamentals of Spectrophotometry
BONUS: Chemical Kinetics
Sections
SI Units
Metric Prefixes
Chemical Concentrations
Volumetric Analysis
Volumetric Titrations

Classical Stoichiometric Methods involve the use of both volumetric methods (titrations) and gravimetric methods.

Titrations

Example #1: When dealing with volumetric calculations we utilize a stoichiometric chart

Example #2: Iron (III) can be oxidized by an acidic K2Cr2O7 solution according to the net ionic equation below. How many microliters of a 0.250 M FeCl2 are needed to completely react with 9.12 g of a compound containing 41.5% weight K2Cr2O7?

Cr2O72-  +  6 Fe2+  + 14 H+   →   2 Cr3+  +  6 Fe3+   +  7 H2O

Titrations Calculations

Example #3: Magnesium reacts with HCl according to the reaction below. How many grams of 5.310% by weight of aqueous magnesium are required to provide a 25% excess to react with 75.0 mL of 0.0550 M HCl.

Mg (s)  +   2 HCl (aq)  →  MgCl2 (aq) +  H2 (g) 

Example #4: The density of 2.20 M solution of methanol (CH3OH) is 0.976 g/mL. What is the molality of the solution? The molar mass of methanol is 31.034 g/mol.

Example #5: A 0.4317 g sample of CaCO3 (MW: 100.09 g/mol) is added to flask that also contained 12.50 mL of 1.530 M HBr.

CaCO3 (aq)  +  2 HBr (aq)  →  CaBr2 (aq)  +  H2O (l)  +  CO2 (g)

Additional water is then added to create a 250.0 mL of Solution A. Next 20.00 mL aliquot of solution A is taken and titrated with 0.0980 M NaOH. How many milliliters of NaOH were used? 

NaOH (aq)  +  HBr (aq)  →  H2O (l)  +  NaBr (aq)

Example #6: A 9.2476 g sample of M(OH)2 was mixed with 15.00 mL of 1.530 M HI and diluted to a final 125.0 mL of solution.

M(OH)2 (aq)  +  2 HI (aq)  →  2 H2O (l)  +  MCl2 (aq)

A 12.00 mL aliquot of this diluted solution was taken and titrated with 18.23 mL of 0.0695 M NaOH.

NaOH (aq)   +  HI (aq)  → H2O (l)  +  NaCl (aq)

What is the identity of the metal representing M? 

Example #7: A 6.2034 g sample of Cu(OH)n was mixed with 25.00 mL of 2.250 M Hl and diluted to a final 250.0 mL of solution.

Cu(OH)n (s)  +  n HI (aq)  →  CuIn (aq)  +  n H2O (l)

A 50.00 mL aliquot of this solution was taken and titrated with 16.25 mL of 0.1250 M KOH. What is the value of n?

KOH (aq)  +  HI (aq)  →  H2O (l)  +  NaI (aq)

Practice: A 1.000 g sample of Na2CO3 (MW: 105.99 g/mol) is dissolved in enough water to make 200.0 mL of solution. A 25.00 mL aliquot required 32.18 mL of HCl to completely neutralize it. What is the molar concentration of HCl? 

Na2CO3 (aq)  + 2 HCl (aq)  →  2 KCl (aq)  +  H2O(l)  +  CO2  (g)