Advanced Chemistry Lab Manual

Millbrook School 2014-15

Ms. Ellena Bethea

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General Information

Safety

Lab Report

Informal

Formal

Unit 1: Aqueous Reactions

Lab 1: Conductivity of Aqueous Solutions

Lab 2: Single-Replacement Reactions

Lab 3: Double-Replacement Reactions

Lab 4: Properties of Acids and Bases

Lab 5:

Lab

Unit 2: Gases

Unit 3: Thermochemistry

Unit 4: Atomic Structure

Unit 5: Bonding & IMFs

Unit 6: Kinetics

Unit 7: Equilibrium

Unit 8: Spontaneity

Appendix: Common Lab Procedures and Techniques

Bunsen Burner

Buret

Logger Pro

Graphing Data

Inserting Graph into a Document

Vernier Sensors

SpectroVis Plus

pH Sensor

Conductivity Sensor

General Information

Safety

Lab Report

Informal

Formal

Unit 1: Aqueous Reactions

Lab 1: Conductivity of Aqueous Solutions

Print Version

Introduction

When an ionic compound dissolves in water, it dissociates into ions, and the resulting solution will conduct electricity. Dissolving solid sodium chloride in water releases ions according to the equation

NaCl(s) → Na+(aq) + Cl(aq)

What occurs when compounds with more than two atoms, such as CaCl2(s) or KNO3(s) dissolve in water? In this experiment, you will use conductivity data to draw conclusions about the number and formula of various ions produced in aqueous solution.

Procedure

  1. Place a Vernier Conductivity Probe in 50 mL of distilled water with a magnetic stir bar. Set the sensitivity to the 200 μS/cm setting.  Set up Events with Entry as the data-collection mode. Enter Drops as the name of the event.  
  2. Zero the sensor once the sensor reading has stabilized.
  3. Start data collection and then click or tap Keep and enter 0 as the number of drops.
  4. Add 10 drops of the 0.10 M KCl solution to the water in the beaker while stirring continuously. When the sensor reading stabilizes, click or tap Keep and enter 10 as the number of drops.
  5. Continue the process of adding 10-drop aliquots of the electrolyte to the solution until 7 or 8 readings have been added. Then, stop data collection.
  6. Dispose of the beaker contents as directed by your teacher. Rinse the probe tip with deionized water from a wash bottle. Carefully blot the probe dry with a kimwipe.
  7. If the data appear linear, perform a linear fit on the graph. Record the slope.
  8. Repeat the data-collection procedure with 0.10M CaCl2. As before, perform a linear fit on the graph and record the slope. Compare the slope of this graph to that for KCl. Account for the value of the ratio of the slopes.
  9. Next, repeat the experiment with 0.10M KNO3. Before collecting data, make a prediction about how the value of slope of the graph of conductivity vs. drops will compare to the values for the previous two trials. Perform the experiment. Based on the slope of the graph, draw a conclusion about the number of ions produced when each formula unit of KNO3 dissolves in water.
  10. Repeat the process of making a prediction and then testing it using a solution of NH4NO3. From the slope of the graph, draw a conclusion about the number of ions produced when each formula unit of NH4NO3 dissolves in water.
  11. Write equations for the dissociation of KNO3 and NH4NO3 in water.

Waste Disposal and Cleanup

Because the solutions are dilute, they can go down the sink with running water. Return the stock solutions to the central lab bench.  Rinse the stir bar, and return to the central bench. Rinse and dry any beakers used, and return to your lab drawer.

Pre-Lab

  1. Read the procedure. Sketch or summarize it in your lab notebook. Prepare a data table to record your observations.
  2.  We will be working with the following chemicals: KCl, KNO3, CaCl2, and NH4NO3 Look up the Safety Data Sheet for each of these chemical solutions (www.flinnsci.com/msds-search.aspx). You will need to type in the chemical name, not formula. In your lab notebook, write down
  1. Whether any of the chemicals is considered hazardous  (Section 2), flammable (Section 5), and/or stable/reactive (Section 10), and
  2. What you should do if you spill it on your skin (Section 4).

Post-Lab Report (informal)

Make a Claim: What knowledge do you believe you have obtained from this experiment? Note a pattern that you observed in your experimental data.

Support it with Evidence: What specific evidence (data) supports your claim?

 

Reasoning: Explain why the evidence supports your claim.

 

Answer the following questions:

  1. If you repeated the experiment, using 1.00 M solutions of each salt, how would your results compare? Justify your answer.
  2. A friend decides to repeat the experiment with modification. She dissolves 1.00 g of NaCl in 100.mL of water and 1.00 g of NaNO3 in 100.mL of water. She predicts that the conductivities will be the same. Explain why her reasoning is correct, and/or why her reasoning is flawed.
  3. Using your results, what relative conductivity would you expect to observe if you continued the experiment with 0.1 M solutions of
  1. NH4Cl
  2. Na3PO4
  3. CuCl2
  4. Al2(SO4)3

 

Lab 2: Single-Replacement Reactions

Print Version

Lab 3: Double-Replacement Reactions

Print Version

 

Lab 4: Properties of Acids and Bases

Print Version

Lab 5:

Print Version

Lab

Print Version


Unit 2: Gases

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Unit 3: Thermochemistry

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Unit 4: Atomic Structure

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Unit 5: Bonding & IMFs

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Unit 6: Kinetics

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Unit 7: Equilibrium

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Unit 8: Spontaneity

Appendix: Common Lab Procedures and Techniques

Bunsen Burner

Buret

Logger Pro

Graphing Data

Inserting Graph into a Document

Vernier Sensors

SpectroVis Plus

To determine λmax

pH Sensor

Conductivity Sensor