Equilibrium with Common Ion

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VIDEO LINKS:

Lab Experiments (Write protocols and perform experiments based on these):

Demonstration (Optional):

  1. Equilibrium simulation
  2. Study of Le Chatelier’s principle with cobalt compounds
  3. Study of Le Chatelier’s principle with NO2
  4. pH demo

The prelab must include Experimental Protocol, Chemical Table and Equipment Table.

The lab report requires all sections (including prelab sections) to be completed in one document.

Experimental Protocol

(Analysis) Watch the experiment videos.  Take notes on the protocol.  Stop the video and re-watch as necessary to acquire the details of the procedure.  Write out the protocol for each part of the experiment.  (It can be written in sequential steps.  Complete sentences are not necessary.)  This is the protocol you will follow, so be detailed.

Chemical Table

(Representation) Prepare your chemical table including the materials you will use in the experiment.  Here is a general template that you may use.
Chemical Name Chemical Formula Molar Mass (g/mol) Hazards Reference PPE
Sodium Chloride NaCl 58.5 Skin irritation https://fscimage.fishersci.com/msds/21105.htm  
         
         
         

Equipment Table

(Analysis) Identify the equipment (type AND size) needed for the experiment and include the name and an image of each.  Be sure to describe the equipment, how to use it, and why it is suitable for this use.
Equipment Name Equipment Picture Intended Purpose

Data Collection

(Acquiring competencies) Following your detailed protocol based on the videos, perform all the experiments. Record your observations and take pictures of your key steps in the process.  Your observations and images need to be incorporated in your data section and this section should be as detailed as possible as you will use this information to complete your discussion.

Data Processing

  1. (Representation) Write the chemical equation for the dissociation of NaCl in water.
  2. (Representation) Write the ionization reaction of hydrochloric acid.
  3. (Representation) Write the balanced chemical equation for the reaction between NaCl(aq) and HCl(aq): molecular, complete ionic and net ionic.
  4. (Manipulation) Calculate the molality and percent mass of your salt solution.
  5. (Manipulation) Calculate the concentration of chloride ions assuming the concentration of HCl is 37% by mass, with a density of 1.19 g/mL.
  6. (Assumptions and Analysis) Fill in the following table using the observations and data from your experiments.
Assumptions made Testing the assumption If assumptions are wrong ...
The HCl is 37% by mass.

Discussion

Write a minimum one-page (12 font, single spaced) discussion on the experiment conducted this week. Address at least one question in each category as fully as possible integrating the collected data, providing explanations for the observed trends and evaluating whether your original assumptions about the experiment were validated by the results. The assignment will be graded on completeness, clarity of the explanations and the meaningful integration of the collected and calculated data. Correct grammar and appropriate format for the chemical formulae and chemical reactions is expected. You may use the outline included at the end of this document on how to build your essay to address each category.
  1. (Existing knowledge, research, and views) Explain equilibrium and Le Chatelier’s Principle.
  2. (Analysis) Describe what happens when extra reactants are added to a reaction. Identify at least one relevant example from your experiment.
  3. (Assumptions) Predict what would happen when products build up in a reaction and provide at least one supported argument for your choice.
  4. (Existing knowledge, research, and views) Identify the units for an equilibrium constant and provide a reasonable justification for your answer.
  5. (Analysis) Identify the observation that indicates the formation of a precipitate in this experiment. Identify the precipitate in the experiment.
  6. (Analysis) Identify the role of HCl in this experiment. Give a supported argument for how the solubility of the sodium chloride changes on addition of concentrated HCl.
  7. (Analysis) Give a supported argument identifying how the concentration of the HCl will affect the amount of precipitation formed in the reaction.
  8. (Analysis) Identify at least two potential sources of error in this experiment, and ways to minimize them.
  9. (Lab skills) Identify the safety precautions that should be taken in the lab when handling concentrated hydrochloric acid.
  10. (Lab skills) Identify the correct procedure to dispose of waste concentrated HCl.
  11. (Experimental Design) Create a protocol to test the density of your concentrated HCl solution.
  12. (Experiment design) Propose another experiment that could be used to confirm the identity of the precipitate.
  13. (Experiment design) Propose another experiment that illustrates a chemical equilibrium. Identify the variables that your proposed experiment studies and describe the expected outcome.