Labs for General Chemistry II

INTRODUCTORY MATERIAL

Periodic Table

Tables of Physical Data

LABORATORIES

Lab 1 - Reaction Stoichiometry
- Purpose
  
  To determine the stoichiometry of acid-base reactions by measuring temperature changes which accompany them.
- Goals
  
  1. To learn to use the MicroLab Interface. 2. To practice generating reaction tables. 3. To determine the limiting reagent in a reaction through a measured quantity.
- Introduction
  
  In this lab, you will be investigating reaction stoichiometry by doing a series of mixing experiments using acids and bases in different amounts. ...
- Equipment
  
  4 150 mL beaker, 3 50 mL graduated cylinder, 1 MicroLab interface, 1 MicroLab Thermistor Instruction Sheet, 1 thermistor, 1 deionized water squirt bottle, 1 ring stand, 1 clamp
- Reagents
  
  60 mL 1.5 M HCl(aq), 45 mL 1.0 M H₃PO₄(aq) , 150 mL 1.5 M NaOH(aq)
- Lab Procedure
  
  1. Open the MicroLab program. 2. Calibrate the thermistor as described in the MicroLab instructions provided in the lab. 3. After the calibration is complete, set the MicroLab collection increment to 2 seconds using the instructions provided. ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 2 - Solutions and Spectroscopy
- Solutions and Spectroscopy
  - Purpose
    
    To determine the concentration of a copper sulfate (CuSO₄) solution, and to duplicate its concentration by two methods.
  - Goals
    
    1. To learn how to use a pipet properly. 2. To learn how to dilute a stock solution. 3. To learn how to use a spectrophotometer. 4. To gain practice plotting a calibration curve and use it to determine the concentration of an unknown solution. ...
  - Introduction
    
    A solution is a homogeneous mixture of two or more substances. Simple solutions consist of one solvent and one or more solutes. The solvent is the major liquid component of the mixture in solutions that contain one or more liquids. ...
  - Equipment
    
    1 MicroLab Spectrophotometer, 1 MicroLab Spectrophotometer Instruction Sheet, 6 vials, 2 Serological pipets, 1 pipet bulb, ...
  - Reagents
    
    25 mL 0.5XX M CuSO₄(aq) stock solution, 10 mL CuSO₄(aq) unknown solution , 1 g solid CuSO₄ · 5 H₂O
  - Lab Procedure
    
    1. A spectrophotometer will be set up in your work area. Make sure it is turned on and allow it to warm up. 2. While the spectrophotometer is warming up, obtain two serological pipets, and set up a beaker for waste Cu²⁺ solution. ...
  - Worksheet
    
    You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
- Solutions and Spectroscopy
  - Purpose
    
    To determine the concentration of a copper sulfate (CuSO₄) solution, and to duplicate its concentration by two methods.
  - Goals
    
    1. To learn how to use a pipet properly. 2. To learn how to dilute a stock solution. 3. To learn how to use a spectrophotometer. 4. To gain practice plotting a calibration curve and use it to determine the concentration of an unknown solution. ...
  - Introduction
    
    A solution is a homogeneous mixture of two or more substances. Simple solutions consist of one solvent and one or more solutes. The solvent is the major liquid component of the mixture in solutions that contain one or more liquids. ...
  - Equipment
    
    1 MicroLab Spectrophotometer, 1 MicroLab Spectrophotometer Instruction Sheet, 6 vials, 2 Serological pipets, 1 pipet bulb, ...
  - Reagents
    
    25 mL 0.5XX M CuSO₄(aq) stock solution, 5 drops CuSO₄(aq) unknown solution , 1 g solid CuSO₄ · 5 H₂O
  - Lab Procedure
    
    1. A spectrophotometer will be set up in your work area. Make sure it is turned on and allow it to warm up. 2. While the spectrophotometer is warming up, obtain two serological pipets, and set up a beaker for waste Cu²⁺ solution. ...
  - Worksheet
    
    You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 3 - Freezing Point Depression
- Purpose
  
  To predict and measure the freezing point depression caused by a solute in a solvent.
- Goals
  
  1. To learn to accurately measure a freezing point depression for a solution. 2. To learn to use the molar mass of a solute to calculate the colligative molality. 3. To learn to use colligative molality to calculate the resulting freezing point depression.
- Introduction
  
  A solution is a homogeneous mixture of two or more substances. For the common two-component solution, the substance present in the major proportion is called the solvent and that in the minor proportion is called the solute. ....
- Equipment
  
  1 crystallization dish, 1 100 mL graduated cylinder, 1 30 mL beaker, 1 digital thermometer, 1 tongs, 1 spatula, 1 hot plate
- Reagents
  
  ~9 g stearic acid, ~2 g lauric acid
- Lab Procedure
  
  Prepare a hot water bath in your crystallization dish by heating about 85 mL of tap water on your hot plate (~1/2 filled). Use a graduated cylinder to measure the water. Medium heat should suffice. You do not want the water to boil. ....
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 4 - Calorimetry
- Purpose
  
  To determine if a Styrofoam cup calorimeter provides adequate insulation for heat transfer measurements, to identify an unknown metal by means of its heat capacity and to determine a heat of neutralization and a heat of solution.
- Goals
  
  1. To perform simple calorimetry experiments. 2. To use calorimetry results to calculate the specific heat of an unknown metal. 3. To determine heat of reaction (ΔH) from calorimetry measurements.
- Introduction
  
  Heat and work are the two most common ways for a system to exchange energy with its surroundings. The work term in reactions that do not involve gases is zero, so all of the energy change results in heat. ...
- Equipment
  
  1 400 mL beaker, 2 Styrofoam cups with lid, 1 18 x 150 mm test tube, 1 test tube holder, 1 150 mL beaker, 1 250 mL beaker, 1 50 mL beaker, 2 100 mL graduated cylinders, 1 hot plate, ...
- Reagents
  
  ~20 g metal unknowns, ~50 mL 1.5 M NH₃, ~50 mL 1.5 M H₃PO₄, ~10 g NH₄H₂PO₄, deionized water
- Lab Procedure
  
  1. Start the MicroLab Interface and calibrate the thermistor as described in the MicroLab instructions provided in the lab. 2. Set the MicroLab collection increment to 5 seconds, using the detailed instructions provided in the lab. ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 5 - Determinations of an Equilibrium Constant
- Purpose
  
  To determine the equilibrium constant for the reaction: ...
- Goals
  
  1. To gain more practice using a pipet properly. 2. To gain more practice diluting stock solutions. 3. To gain more practice using a spectrophotometer. ...
- Introduction
  
  A typical chemical equation has the following form:
  aA + bB → cC + dD
  This form of the equation assumes that the reaction proceeds completely to products. In practice, many reactions do not proceed to completion. ...
- Equipment
  
  1 MicroLab Spectrophotometer, 1 MicroLab Spectrophotometer Instruction, 6 vials, 3 Serological pipets, 1 pipet bulb, 3 30 mL beakers for reagents, 6 13x100 mm test tubes for mixtures, ...
- Reagents
  
  ~10 mL 0.100 M Fe(NO₃)₃ in 0.2 M HNO₃, ~10 mL 5.00 x 10^-4M NaSCN in 0.2 M HNO₃, ~15 mL 0.002 M Fe(NO₃)₃ in 0.2 M HNO₃, ...
- Lab Procedure
  
  1. A spectrophotometer will be set up in your work area. Make sure it is turned on and allow it to warm up. 2. While the spectrophotometer is warming up, obtain three serological pipets, and label a beaker for waste. ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 6 - Mixtures of Acids and Bases
- Purpose
  
  To investigate the resulting pH's of different mixtures of acid and base solutions.
- Goals
  
  1. To calculate the pH of pure acid and base solutions. 2. To calculate the pH of mixtures of acid and base solutions. 3. To measure the pH of pure acid and base solutions and mixtures of these solutions. ...
- Introduction
  
  Brønsted acids are defined as proton donors. When placed in water, Brønsted acids (HA) donate a proton to water to produce the conjugate base of the acid (A^-) and a hydronium ion (H3O⁺) according to the following reaction. ...
- Equipment
  
  1 25 x 150 mm test tube, 1 400 mL beaker (to hold the test tube), 1 glass stir rod, 1 10 mL graduated cylinder, 1 100 mL beaker, 2 30 mL beakers, 1 MicroLab Interface, 1 MicroLab pH Measurement Instruction Sheet ...
- Reagents
  
  ~60 mL, 0.1 M NaOH, 10 mL, 0.1 M HCl, 10 mL 0.1 M NH₄Cl, 10 mL 0.1 M NaC₂H₃O₂, ~15 mL pH 4.00 buffer, ~15 mL pH 7.00 buffer, ~15 mL pH 10.00 buffer
- Lab Procedure
  
  In this experiment, you will be using pH electrodes connected to the MicroLab Interface. pH electrodes have a thin glass bulb at the tip. They break easily and are costly to replace. Be careful not to shove the electrode into the bottom of a beaker or drop the electrode. ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 7 - Buffers
- Purpose
  
  To prepare buffers and measure the pH of each, and to prepare a buffer at a specific pH.
- Goals
  
  1. To learn to prepare buffers by both the direct and indirect methods. 2. To learn to identify solutions that are buffers. 3. To understand the how a buffer resists changes in pH upon addition of acid or base solutions.
- Introduction
  
  In dilute aqueous solutions, weak acids are slightly dissociated. They produce a small concentration of hydronium ion (H3O⁺) and an equal concentration of the conjugate base of the acid. Such dissociation reactions are equilibria, and equilibrium mathematics can be used to calculate concentrations of the species present in solution. ...
- Equipment
  
  2 30 mL beakers, 2 100 mL volumetric flasks, 1 10.0 mL volumetric pipet, 1 pipet bulb, 1 50 mL graduated cylinder, 1 10 mL graduated cylinder, 1 50 mL beaker, 1 100 mL beaker, 1 glass stir rod, 1 MicroLab Interface, 1 MicroLab pH Measurement Instruction Sheet, 1 pH electrode in pH 7.00 buffer ...
- Reagents
  
  ~10 mL 6.0 M acetic acid (HC₂H₃O₂), <10 g solid sodium acetate trihydrate (NaC₂H₃O₂ · 3 H₂O), ~25 mL 1.0 M NaOH, 3 g solid Na₂HPO₄ · 7 H₂O, TBD solid NaH₂PO₄ · H₂O or solid Na₃PO₄ · 12 H₂O, ...
- Lab Procedure
  
  In this experiment, you will be using pH electrodes connected to the MicroLab Interface. pH electrodes have a thin glass bulb at the tip. They break easily and are costly to replace. Be careful not to shove the electrode into the bottom of a beaker or drop the electrode. There is a protective guard around the tip, which should remain in place at all times.
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 8 - Titration Curves
- Purpose
  
  To determine the equivalence points of two titrations from plots of pH versus mL of titrant added.
- Goals
  
  1. To gain experience performing acid-base titrations with a pH meter. 2. To plot titration curves of pH vs mL of titrant added. 3. To determine the equivalence point of a titration from a titration curve. 4. To determine the pKa of an analyte from a titration curve.
- Introduction
  
  A titration is an analytical procedure in which a reaction is run under carefully controlled conditions. The stoichiometric volume of one reactant of known concentration, the titrant, that is required to react with another reactant of unknown concentration, the analyte, is measured. ...
- Equipment
  
  1 MicroLab Interface, 1 MicroLab pH Measurement Instruction Sheet, 1 pH electrode in pH 7.00 buffer, 2 30 mL beakers, 2 50 mL beakers, 1 250 mL beaker, 1 100 mL graduated cylinder, 1 20.00 mL volumetric pipet, 1 pipet bulb, 1 magnetic stir plate, 1 magnetic stir bar, 1 25 mL buret, 1 ring stand ...
- Reagents
  
  ~25 mL 0.20 M potassium hydrogen phthalate (KHP), ~30 mL 0.20 M sodium hydroxide (NaOH), 3 drops phenolphthalein solution, ~25 mL 0.10 M sodium carbonate (Na₂CO₃), ~30 mL 0.20 M hydrochloric acid (HCl), 3 drops methyl orange solution, ~15 mL pH 4.00 buffer, ...
- Lab Procedure
  
  In this experiment, you will be using pH electrodes connected to the MicroLab Interface. pH electrodes have a thin glass bulb at the tip. They break easily and are costly to replace. Be careful not to shove the electrode into the bottom of a beaker or drop the electrode. ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 9 - Solubility Product Constants
- Purpose
  
  To measure the solubility product constant (K_sp) of copper (II) iodate, Cu(IO₃)₂.
- Goals
  
  1. To measure the molar solubility of a sparingly soluble salt in water. 2. To prepare a calibration curve based on complex ion formation for absorbance enhancement. 3. To calculate the solubility product constant (K_sp) of a sparingly soluble salt from its molar solubility. 4. To confirm the common ion effect on the molar solubility of a sparingly soluble salt.
- Introduction
  
  In previous introductory chemistry courses, you learned some basic solubility rules that are useful in determining if an ionic solid will dissolve in water. Solids that dissolve completely, such as NaCl and NH₄NO₃, were referred to as "soluble" and others that did not dissolve completely, such as AgCl and BaSO₄, were referred to as "insoluble". In fact, very few ionic solids are completely insoluble, meaning that they will not form any ions when placed in aqueous solution.
- Equipment
  
  15 13 x 100 mm test tubes, 5 stoppers, 1 test tube rack, 1 spatula, 1 glass stir rod, 1 MicroLab Spectrophotometer, 1 MicroLab Spectrophotometer Instruction Sheet, 6 vials, ...
- Reagents
  
  ~0.25 g solid Cu(IO₃)₂, ~5 mL 5.0 x 10^-4 M Cu(NO₃)₂, ~10 mL 1.0 x 10^-3 M Cu(NO₃)₂, ~10 mL 5.0 x 10-3 M Cu(NO₃)₂, ~5 mL 1.0 x 10^-2 M Cu(NO₃)₂, ~5 mL 5.0 x 10^-3 M KIO₃, ...
- Lab Procedure
  
  1. A spectrophotometer will be set up in your work area. Make sure it is plugged in and allow it to warm up. 2. While the spectrophotometer is warming up, label five clean, dry test tubes A - E and set up a beaker for waste. 3. Fill each of the five test tubes to a depth of 4 fingers or approximately 3/4 full with the following solutions. ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 10 - Electrochemical Cells
- Electrochemical Cells
  - Purpose
    
    To see how changes in concentration and pH affect the potential in an electrochemical cell, and confirm the Nernst equation.
  - Goals
    
    1. To examine how standard reduction potentials are measured. 2 To relate concentration changes to changes in cell potential.
  - Introduction
    
    A galvanic cell is an electrochemical cell in which the spontaneous electrochemical reaction proceeds, that is, ΔG for the reaction is negative. The free energy decrease for a galvanic cell is proportional to the cell potential. ...
  - Equipment
    
    1 MicroLab Interface, 1 voltmeter alligator clip leads, 1 400 mL beaker for rinsings, 1 100 mL beaker, 1 salt bridge assembly, 1 hand-held pH meter, 1 deionized water squirt bottle, 1 eye dropper
  - Reagents
    
    100 mL 0.1 M Zn(NO₃)₂ (in covered plastic container), 100 mL 0.1 M Cu(NO₃)₂ (in covered plastic container), 100 mL 0.1 M AgNO₃ (in covered plastic container), ...
  - Lab Procedure
    
    1. Open the MicroLab program. Make sure the alligator clip leads are connected to the interface. 2 Calibrate the mV probe as described in the MicroLab instructions provided in the lab. ...
  - Worksheet
    
    You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
- Electrochemical Cells
  - Purpose
    
    To see how changes in concentration and pH affect the potential in an electrochemical cell, and confirm the Nernst equation.
  - Goals
    
    1. To examine how standard reduction potentials are measured. 2 To relate concentration changes to changes in cell potential.
  - Introduction
    
    A galvanic cell is an electrochemical cell in which the spontaneous electrochemical reaction proceeds, that is, ΔG for the reaction is negative. The free energy decrease for a galvanic cell is proportional to the cell potential. ...
  - Equipment
    
    1 MicroLab Interface, 1 voltmeter alligator clip leads, 1 400 mL beaker for rinsings, 1 100 mL beaker, 1 salt bridge assembly, 1 hand-held pH meter, 1 deionized water squirt bottle, 1 eye dropper
  - Reagents
    
    100 mL 0.1 M Zn(NO₃)₂ (in covered plastic container), 100 mL 0.1 M Cu(NO₃)₂ (in covered plastic container), 100 mL 0.1 M AgNO₃ (in covered plastic container), ...
  - Lab Procedure
    
    1. Open the MicroLab program. Make sure the alligator clip leads are connected to the interface. 2 Calibrate the mV probe as described in the MicroLab instructions provided in the lab. ...
  - Worksheet
    
    You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......
Lab 11 - Chemical Kinetics
- Purpose
  
  To determine the rate law for the reaction 2 I⁻ + S₂O₈²⁻ → I₂ + 2 SO₄²⁻ .
- Goals
  
  1. To relate changes in reactant concentrations to changes in reaction rate. 2. To calculate a rate constant from experimental data.
- Introduction
  
  Chemical kinetics deals with the speed, or rate, of a reaction and the mechanism by which the reaction occurs. We can think of the rate as the number of events per unit time. The rate at which you drive (your speed) is the number of miles you drive in an hour (mi/hr). For a chemical reaction the rate is the number of moles that react in a second. ...
- Equipment
  
  2 50 mL burets, 2 50 mL graduated cylinders, 4 100 mL beakers, 4 50 mL beakers, 1 magnetic stir plate, 1 magnetic stir bar, 1 10.00 mL volumetric pipet, 1 pipet bulb, 1 ring stand with buret clamp, 1 deionized water squirt bottle
- Reagents
  
  ~90 mL 0.200 M KI, ~90 mL 0.100 M (NH₄)₂S₂O₈, ~60 mL 0.0050 M Na₂S₂O₃, ~30 mL 0.200 M KCl, ~30 mL 0.100 M (NH₄)₂SO₄, ~30 mL 3% starch solution
- Lab Procedure
  
  Five different solutions with similar names are used in this experiment. Label the glassware so you will not mix things up. For example: 50 mL buret for KI, 100 mL beaker for obtaining KI, 50 mL beaker for KI dispensed from buret, 50 mL buret for (NH₄)₂S₂O₈, ...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab......