Prak. Kimia fisika Isoterm Absorbsi

Summary

This practical chemistry session explores the titration of acetic acid solutions to determine their concentration and the effect of activated charcoal on absorption. The procedure includes preparing acetic acid solutions, performing titration with NaOH, and using phenolphthalein as an indicator to detect the endpoint. After adding activated charcoal to the solutions, the process is repeated to observe changes in titration volumes. The experiment aims to demonstrate how activated charcoal influences acetic acid absorption, with the hypothesis that charcoal reduces the concentration, as evidenced by decreased titration volumes.

Takeaways

• 😀 The practical experiment involves performing an autopsy with key materials like NaOH, H3COH, and active charcoal.
• 😀 The first stage of the experiment is creating acetic acid solutions with concentrations of 0.5M and 0.25M using a stock solution.
• 😀 During the first part of the experiment, the mass of acetic acid is determined before autopsy and again after using active charcoal.
• 😀 It's important to label each Erlenmeyer flask with different concentrations of acetic acid (1M, 0.5M, and 0.25M) and perform duplicate measurements.
• 😀 When transferring different concentrations of acetic acid, separate pipettes or cleaning the pipette thoroughly are required to avoid contamination.
• 😀 After the acetic acid is in the Erlenmeyer flasks, titration is performed with NaOH and the endpoint is indicated by a color change to purple.
• 😀 If too much NaOH is added during titration, the solution may turn pink, which is an indication of excess base.
• 😀 Active charcoal (a black powder) is added to the acetic acid solution to observe its adsorption effects, with the solution being left to react for 30 minutes.
• 😀 After the 30-minute reaction time, the mixture is filtered using a gravity filtration method, and the filtrate is collected for further titration.
• 😀 The second part of the experiment involves titrating the acetic acid after the charcoal has been used, comparing the volume of NaOH required before and after charcoal treatment.
• 😀 The hypothesis suggests that the acetic acid treated with charcoal will require less NaOH for titration due to adsorption of the acid by the charcoal.

Q & A

What is the main objective of the experiment described in the transcript?

The main objective of the experiment is to determine the concentration or mass of acetic acid before and after autopsy, using titration with NaOH and phenolphthalein as an indicator.

What materials are needed for the experiment?

The materials needed include NaOH 1M, acetic acid solutions (1M, 0.5M, 0.25M), activated charcoal, phenolphthalein (PP) as an indicator, Erlenmeyer flasks, pipettes, burets, and a balance.

Why is it necessary to use different pipettes for different concentrations?

Different pipettes must be used for different concentrations to avoid contamination between the different solutions. If only one pipette is available, it should be washed with distilled water and the solution before taking a new sample.

What role does activated charcoal play in this experiment?

Activated charcoal is used in the second part of the experiment to absorb acetic acid from the solution. The purpose is to observe the change in titration results after the charcoal is introduced, demonstrating its absorption capability.

What is the purpose of the 30-minute waiting period after adding activated charcoal?

The 30-minute waiting period allows the activated charcoal to absorb the acetic acid, ensuring that the absorption process is complete before proceeding to the next steps of filtration and titration.

How is the titration process conducted in the experiment?

The titration process involves adding NaOH from a buret to the acetic acid solution in an Erlenmeyer flask. Phenolphthalein is used as an indicator, with the solution changing color from colorless to purple or pink as the titration reaches the endpoint.

What color change indicates the endpoint of the titration?

The endpoint of the titration is indicated by a color change from colorless to purple, or in some cases, a pale pink color, depending on the concentration and volume of NaOH used.

Why is it important to measure the volume of NaOH used during titration?

Measuring the volume of NaOH used during titration is crucial to calculate the concentration of acetic acid in the solution. The volume of NaOH required to reach the endpoint directly correlates to the amount of acetic acid present in the sample.

What is the expected difference in titration results with and without activated charcoal?

It is expected that less NaOH will be required in the titration with activated charcoal, as the charcoal will absorb some of the acetic acid, thereby lowering its concentration and affecting the titration results.

How is the mass of activated charcoal measured in the experiment?

The mass of activated charcoal is measured using a balance. A specific amount, typically 1 gram, is weighed out and added to the acetic acid solution for the adsorption process.