Honors Chemistry Lab Fall
By: Mary McHale
Online: < http://cnx.org/content/col10456/1.16>
This selection and arrangement of content as a collection is copyrighted by Mary McHale.
It is licensed under the Creative Commons Attribution License: http://creativecommons.org/licenses/by/2.0/
Collection structure revised: 2007/11/15
For copyright and attribution information for the modules contained in this collection, see the " Attributions" section at the end of the collection.
Honors Chemistry Lab Fall
Table of Contents
Chapter 1. Initial Lab: Avogradro and All That
Chapter 2. Stoichiometry: Laws to Moles to Molarity
Experiment 2: Stoichiometry: Laws to Moles to Molarity
Chapter 3. VSEPR: Molecular Shapes and Isomerism
Chapter 4. Beer's Law and Data Analysis
Extracting Quantitative Information
PreLab: Spectrophotometry and Data Analysis – Beer’s Law
Chapter 5. Hydrogen and Fuel Cells
Hydrogen and Fuel Cells Experiment
Chapter 6. The Best Table in the World
Relative Reactivity of Metals and the Activity Series
Part 1. Reactions of Metals with Water
Part 2. Reactions of Metals with HCl
Part 3. Reactions of Metals with Other Metal Ions
One station set up that all sections will rotate through
Pre-Lab 5: The Best Table in the World!
Report 5: The Best Table in the World!
Part 1. Reactions of Metals with Water
Part 3. Reactions with Other Metal Ions
Part I. Predicting bond type through electronegativity differences.
Part II. Weak and strong electrolytes
Instructions for MicroLab Conductivity Experiment
Part III. Electrolyte strength and reaction rate
Part I. Bonding of chemicals in solution
Part I. Predicting bond type through electronegativity differences.
Part II. Weak and strong electrolytes
Part III. Electrolyte strength and reaction rate
Chapter 8. Solid State and Superconductors
Solid State Structures and Superconductors
Packing of more than one type of ion (binary compounds) in a crystal
Coordination number and interstitial sites
Synthesis of solid state materials
Use of the Solid State Model Kit:
4. Interstitial sites and coordination number (CN)
· Use the L template and insert 6 rods in the parallelogram portion of the
· Construct the pattern shown below. Be sure to include a z=1 layer. 1 is a
green sphere while 1 and 2 are blue spheres. The 0 indicates a 4.0 mm
spacer tube; the 2 is an 18.6 mm spacer.
Zinc Blende and Wurtzite: Zinc Sulfide
Pre-Lab: Solid State and Superconductors
Report: Solid State and Superconductors
A. Simple Cubic Unit Cells or Primitive Cubic Unit Cells (P)
B. Body-Centered Cubic (BCC) Structure
C. The Face Centered Cubic (FCC) Unit Cell
a. Fill out the following table for a FCC unit cell.
Oxidation of an alcohol with acidified potassium dichromate(VI) solution
Oxidation of an alcohol with acidified potassium permanganate (VII)
Saponification of a vegetable oil
Pre-Lab: Introductory Organic Reactions
Oxidation of an alcohol with acidified potassium dichromate(VI) solution.
Oxidation of an alcohol with acidified potassium permanganate (VII) solution
Saponification of a vegetable oil
Transitions Metals: Synthesis of an Inorganic Compound (trans-
dinitrobis(ethylenediamine)cobalt(III) nitrate)
Chapter 11. Physical Properties of Gases
Tygon tube in liquid nitrogen:
Pre-Lab: Physical Properties of Gases
Report: Physical Properties of Gases
Chapter 1. Initial Lab: Avogradro and All That
Initial Lab: Avogadro and All ThatExperiment 1
Objective
The purpose of this laboratory exercise is to help you familiarize yourself with the layout of the laboratory including safety aids and the equipment that you will be using this year.
Then, to make an order-of-magnitude estimate of the size of a carbon atom and of the number
of atoms in a mole of carbon based on simple assumptions about the spreading of a thin film of
stearic acid on a water surface
Grading
Pre-lab – not required for the first lab
Lab Report (90%)
TA points (10%)
Before coming to lab……
Read the following:
Lab instructions
Background Information
Concepts of the experiment
Print out the lab instructions and report form.
You may fill out the lab survey, due at the beginning of the lab, for extra credit if you wish.
Read and sign the equipment responsibility form and the safety rules, email Ms Duval at
nduval@rice.edu to confirm completing this requirement by noon on August 31st Introduction
Since chemistry is an empirical (experimental) quantitative science, most of the experiments you will do involve measurement. Over the two semesters, you will measure many different types of
quantities – temperature, pH, absorbance, etc. – but the most common quantity you will measure
will be the amount of a substance. The amount may be measured by (1) weight or mass (grams),
(2) volume (milliliters or liters), or (3) determining the number of moles. In this experiment we will review the methods of measuring mass and volume and the calculations whereby number of
moles are determined.
Experimental Procedure
We will start in the amphitheater of DBH (above DBH 180) for demonstrations: oxygen, hydrogen
and a mixture of the two in balloons and more besides.
Mandatory Safety talk by Kathryn Cavender, Director of Environmental Health and Safety at Rice.
1. Identification of Apparatus
On your benches, there are a number of different pieces of common equipment. With your TA's
help, identify each and sketch - I know this may sound a trivial exercise but it is necessary so that we are all on the same page.
1. beaker
2. erlenmeyer flask
3. graduated (measuring) cylinder
4. pipette
5. burette
6. Bunsen burner
7. test tube
8. boiling tube
9. watch glass
2. Balance Use
In these general chemistry laboratories, we only use easy-to-read electronic balances – saving you a lot of time and the TA’s a lot of headaches. However, it is important that you become adept at the use of them.
Three aspects of a balance are important:
1. The on/off switch. This is either on the front of the balance or on the back.
2. The "Zero" or "Tare" button. This resets the reading to zero.
2. The "Zero" or "Tare" button. This resets the reading to zero.
3. CLEANLINESS. Before and after using a balance, ensure that the entire assembly is spotless.
Dirt on the weighing pan can cause erroneous measurements, and chemicals inside the
machine can damage it.
4. Turn the balance on.
5. After the display reads zero, place a piece of weighing paper on the pan.
6. Read and record the mass. (2)
7. With a spatula, weigh approximately 0.2 g of a solid, common salt NaCl, the excess salt is
discarded, since returning the excess salt may contaminate the rest of the salt - in this exercise, this is not a big deal but in strict analytical procedures it is.
8. Record the mass (1). To determine how much solid you actually have, simply subtract the
mass of the weighing paper(2) from the mass of the weighing paper and solid (1). Record this
mass (3).You have just determined the mass of an "unknown amount of solid."
9. Now place another piece of weighing paper on the balance and press the Zero or Tare button
then weigh out approximately 0.2 g of the salt (4). Thus, the zero/tare button eliminates the
need for subtraction.
3. Measuring the volume of liquids
When working with liquids, we usually describe the quantity of the liquid in terms of volume,
usual units being milliliters (mL). We use three types of glassware to measure volume – (1)
burette, (2) volumetric pipette, and (3) graduated cylinder.
Examine each piece of equipment. Note that the sides of each are graduated for the graduated
cylinder and the burette. You can read each to the accuracy of half a division.
Put some water into the graduated cylinder. Bend down and examine the side of the water level.
Note that it has a "curved shape." This is due to the water clinging to the glass sides and is called the meniscus. When reading any liquid level, use the center of the meniscus as your
reference point.
Graduated cylinder
1. Look at the graduations on the side of the cylinder. Note that they go from 0 on the bottom and increase upwards. Thus, to get the mass of 10 mL of a liquid from a graduated cylinder, do the
following:
2. Add water up to the 10 mL line as accurately as possible.
3. Dry a small beaker and weigh it (2).
3. Dry a small beaker and weigh it (2).
4. Pour the 10 mL of water from the cylinder into the beaker. Reweigh (1).
5. Subtract the appropriate values to get the weight of the water (3).
Pipette
1. You may find either that 0 is at the spout end or at the top of the pipette. You should be aware of how these graduations go when using each pipette. Thus, to get the mass of 10 mL of a
liquid from a pipette, do the following:
2. Half-fill a beaker with water.
3. Squeeze the pipette bulb and attach to the top of the pipette. Put the spout of the pipette under water and release the bulb. It should expand, drawing the water into the pipette, do not let the water be drawn into the bulb.
4. When the water level is past the last graduation, remove the bulb, replace with your finger, and then remove the pipette from the water.
5. Removal of your finger will allow liquid to leave the pipette. Always run some liquid into a waste container in order to leave the level at an easy-to-read mark.
6. Add 10 mL of water to a pre-weighed dry beaker (5).
7. Weigh (4).
8. Subtract to get the weight of the water (6).
Burette
1. Examine the graduations. Note that 0 is at the top.
2. Using a funnel, add about 10 mL of water. To do this, first lower the burette so that the top is easy to reach.
3. Run a little water from the burette into a waste container. Then turn the burette upside down and allow the rest of the water to run into the container (you will have to open the top to
equalize the pressure).
4. You have just "rinsed your burette." This should be done every time before using a burette –
first rinse with water, then repeat the process using whatever liquid is needed in the
experiment.
5. Fill the burette to any convenient level (half-way is fine). It is a good technique to "overfill"
and then allow liquid to run into a waste container until you reach the appropriate level so that you fill the space from the top to the tip of the burette.
6. Dry a beaker and weigh (8).
7. Add 10 mL of water to a pre-weighed dry beaker (7).
8. Subtract to get the weight of the water (9).
4. Estimation of Avogadro's number
Briefly, as a group with your TA, you will make an approximate (order of magnitude) estimate of Avogadro's number by determining the amount of stearic acid that it takes to form a single layer (called a monolayer) on the surface of water. By making simple assumptions about the way the
stearic acid molecules pack together to form the monolayer, we can determine its thickness, and from that thickness we can estimate the size of a carbon atom. Knowing the size of a carbon atom, we can compute its volume; and if we know the volume occupied by a mole of carbon (in the form
of a diamond), we can divide the volume of a mole of carbon by the volume of an atom of carbon
to get an estimate of Avogadro's number.
Procedure
Special Supplies: 14 cm watch glass; cm ruler; polyethylene transfer pipets; 1-mL syringes; pure distilled water free of surface active materials; disposable rubber gloves (for cleaning own watch glasses in 0.1 M NaOH in 50:50 methanol/water): 13 X 100 mm test tubes with rubber stoppers to
fit.
Chemicals: pure hexane, 0.108 g/L stearic acid (purified grade) solution in hexane. 0.1 M NaOH
in 50:50 methanol/water used for washing the watch glasses.
SAFETY PRECAUTIONS: Hexane is flammable! There must be no open flames in the laboratory
while hexane is being used.
WASTE COLLECTION: At the end of the experiment, unused hexane solvent and stearic acid in
hexane solution should be placed in a waste container, marked "Waste hexane/stearic acid solution in hexane."
Measurement of the volume of stearic acid solution required to cover the water surface
Your TA will do this as a group demonstration:
1. Using a transfer pipette, obtain about 3-4 mL 0.108 g/L stearic acid solution in hexane in a clean, dry 13 X 100 mm test tube. Keep the tube corked when not in use.
2. Fill the clean watch glass to brim with deionized water. One recommended way to do this is to set up your 25 mL burette on a ring stand. Wash and drain the burette with deionized water.
(the deionized water comes from the white handled spouts at each sink)
3. In a freshly cleaned and rinsed beaker, obtain more distilled water and fill the burette. Place your watch glass directly under the burette (about 1 inch or less from the tip) and dispense the water until the entire watch glass is full. You may have to refill the burette 4 or 5 times to do this. With careful dispensing, the surface tension of the water should allow you to fill the
entire watch glass with relative ease.
4. Carefully measure the diameter of the water surface with a centimeter ruler. It should be close to 14 cm, + or - a couple of millimeters. Next, rinse and fill your 1 mL syringe with stearic
acid solution, taking care to eliminate bubbles in the solution inside the syringe.
5. Read and record the initial volume of the syringe (1 mL is always a good place to start.)
6. Then add the stearic acid solution drop by drop to the water surface. Initially, the solution will spread across the entire surface, and it will continue to do so until a complete monolayer of
stearic acid has been formed. If your first few drops do not spread and evaporate quickly,
either your water or watch glass is still dirty. As this point is approached, the spreading will become slower and slower, until finally a drop will not spread out but will instead sit on the
surface of the water (looking like a little contact lens). If this "lens" persists for at least 30 s, you can safely conclude that you have added 1 drop more than is required to form a complete
monolayer.
7. Now, read and record the final volume reading of the syringe.Takes 10 min
8. Thoroughly clean the watch glass (or get another one), and repeat the experiment. Repeat until the results agree to within 2 or 3 drops (0.04 ml).
When you have completed all of your measurements, rinse your syringe with pure hexane, and
dispose of all the hexane-containing solutions in the waste collection bottle provided.
Calculation Of Avogadro's Nu