Titration Vocabulary

Onderzoekspracticum: Bepaling van NaOH-concentratie mbv Titratie

Attitudes

• Veiligheid:
  • Lab coat worn and closed properly.
  • Safety of classmates ensured.
  • Safety glasses worn.
• Order and Cleanliness:
  • Glassware cleaned.
  • Hair arranged properly.
  • Backpack stowed away.
  • Table and sink cleaned.
  • Waste sorted appropriately.
  • All materials returned to their correct places.
• Work Ethic:
  • Proper use of materials demonstrated.
  • Smooth teamwork during the experiment.
  • Attention paid to P- and H-phrases (precautionary and hazard statements).
  • No talking with other groups during the experiment.
• Conclusion:
  • Reflection on the experiment conducted.

Doel van het Practicum (Objectives of the Practicum)

• Determination of the concentration of sodium hydroxide (NaOH) by titration with a standardized hydrochloric acid (HCl) solution (0.10 mol/L).
• Learning how to use volumetric equipment: volumetric flask, pipette, pipette pump, and burette.

Oriënteren - Onderzoeksvraag (Orientation - Research Question)

• Onderzoeksprobleem (Research Problem): Determine the concentration of NaOH by titration with a standardized HCl solution (0.10 mol/L). The NaOH solution will be provided.

Voorbereiden (Preparation)

A - Informatie verzamelen = vooronderzoek (Gathering Information = Preliminary Research)

• Principle of titration and acid-base indicators.

B - Benodigdheden (Materials Required)

• Materiaal (Materials):
  • Burette
  • Retort stand
  • Burette clamp
  • Erlenmeyer flask (250 mL)
  • Graduated cylinder (100 mL)
  • Pipette (10 mL)
  • Funnel
  • White card (as background)
• Stoffen (Chemicals):
  • Phenolphthalein
  • Distilled water
  • NaOH solution (H 315-319 P 280.1+3-305+351+338)
  • HCl solution (0.10 mol/L) - no H- and P-phrases indicated.

Uitvoeren (Execution)

Werkwijze (Procedure)

• Transfer exactly 10 mL of the NaOH solution into an Erlenmeyer flask using a pipette; add a few drops of phenolphthalein and homogenize the solution.
• Fill the burette with the 0.10 mol/L HCl solution.
• Record the initial reading of the HCl solution in the burette.
• Titrate until the solution becomes colorless.
• Record the final reading of the HCl solution in the burette.
• Perform the titration at least three times and calculate the average volume of HCl added.
• Drain the burette and rinse it by letting tap water run through it.
• Proefopstelling: A drawing showing the setup of the experiment with all the pieces labelled.

Meetgegevens (Measurement Data)

• Table to record:
  • Initial burette reading (mL)
  • Final burette reading (mL)
  • Added volume of 0.10 mol/L HCl (mL)
  • Data recorded for Titration 1, Titration 2, and Titration 3.
  • Average added volume (mL)

Berekeningen (Calculations)

• Calculate the concentration of NaOH in the solution, expressed in mol/L.
• Calculate the concentration of NaOH in the solution, expressed in m/V%.

Rapporteren - Reflecteren (Reporting - Reflection)

Evalueren uitvoering (Evaluating Execution)

• Does the calculated concentration match the value on the label? If not, what could be the reasons for the difference? Possible reasons include measurement errors, inaccurate standardization of titrant, or degradation of NaOH standard. Possible sources of error in the titration are misreading the burette, overshooting the endpoint adding too much titrant or inaccurate measurement of the initial sample volume. 2 main equation involved in the calculations are listed below:
  • Molarity (M) = \frac{\text{moles of solute}}{\text{volume of solution in liters}}
  • M1V1 = M2V2 where M is molarity and V is volume. 1 and 2 represent the acid and base respectively. Ensure you have a balanced chemical equation to account for stoichiometry if the acid and base do not react in a 1:1 molar ratio.