Mole Concept Experiment

• Bicol University College of Agriculture and Chemistry
• Qualitative Chemistry
• Instructor: Hannah Angelie H. Olivarez, RCh
• Mole Ratios and Reaction Stoichiometry (Experiment)
• Theoretical approach to obtain mole-to-mole ratios


  1. Balance the chemical equations

  2. Determine mole ratios from balancing coefficients
• Experimental yield


  Mass of collected sodium chloride product
• Theoretical yield


  Maximum mass of product that could be obtained from a reaction provided that no errors occur
• Good experimental practices in the lab (with minimum error) generally result in a high percent yield, where the experimental yield closely approaches the theoretical yield
• Materials and Equipment


  • Solid sodium bicarbonate (NaHCO3)
  • Bunsen burner
  • solid sodium carbonate (Na2CO3)
  • small beaker
  • 6 M hydrochloric acid (HCl)
  • dropper pipette
  • electronic balance
  • wire gauze
  • evaporating dish
  • stand and ring clamp
  • watch glass (to fit as a cover for the evaporating dish)
• Be especially careful when handling the 6 M HCl (aq), as it can cause chemical burns to the skin. If any acid spills on you, rinse immediately under running water for up to 15 minutes and report the accident to your instructor. Acid spills may also be neutralized using the sodium bicarbonate solution by the sinks. Also, be sure to exercise appropriate caution when using the Bunsen burner and handling hot equipment.
• Procedure


  1. Measure and record the mass of your clean dry evaporating dish + watch glass

  2. Carefully add 0.3 – 0.4 g of solid sodium bicarbonate (NaHCO3) to the evaporating dish

  3. Obtain about a 5-mL quantity of hydrochloric acid (HCl) in your small beaker. Then using your dropper pipette, add the HCl drop by drop to the sodium bicarbonate in the evaporating dish

  4. Assemble the stand, ring clamp and wire gauze apparatus for heating

  5. Gently heat the solution in the covered evaporating dish with a Bunsen burner flame in order to remove the water generated in the reaction (as well as any excess HCl present)

  6. After allowing the evaporating dish to cool to room temperature, measure and record the mass of the evaporating dish + watch glass + residue (NaCl)

  7. Repeat steps 1 to 6 with a 0.3 – 0.4 g sample of sodium carbonate (Na2CO3)

  8. The waste from this experiment may be disposed of in the sink
• Analysis: Experimental Mole-to-Mole Ratios

  1. Convert the initial mass of sodium bicarbonate (or carbonate) reactant to moles (via its molar mass)

  2. Convert the final mass of collected sodium chloride product to moles (via its molar mass)

  3. Obtain the simplest whole number mole-to-mole ratio by dividing both the reactant and product moles by the lower of the two values
• Analysis: Percent Yields


  1. Calculate the theoretical yield of NaCl for both reactions via standard mass-to-mass stoichiometry

  2. Determine your percent yield for each reaction using the calculated theoretical yields along with your experimental yields of NaCl
• Reaction A: Sodium Bicarbonate and Hydrochloric Acid
• Reaction B: Sodium Carbonate and Hydrochloric Acid
• Is your percent yield here for reaction 4 greater than or less than 100%? Give one possible source of error that could explain the percent yield you obtained.