PADM 5600 Chapter : Landons Project

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azuremammoth471

15 Mar 2019

School

LSU

Department

Public Administration

Course

PADM 5600

Professor

All

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Document Summary

Materials: 2 liter bottle, bicycle pump, wine cork, water. How to make an imitation of a cloud. Making a fake cloud is pretty simple if you know what you are doing. You need to add just enough water at the bottom of a 2 liter bottle. Take off the cap and replace it with a rubber cork, make sure the cork has a hole running through the top to the bottom. Place a hand pump on top of the cork where the hole is. Start pumping air into the bottle and start to feel the air pressure. After that place your finger to cover the hole on top of the cork. Keep pumping until it feels like a new bottle of soda. Hold onto the bottle ,carefully, and release the cork to find a cloud in the bottle! Well when pumping the bottle forces the molecules to squeeze together.

Related Questions

I need help writing a purpose for a chemistry experiment. I feel I was always do a great job, but my professor always disagrees and Iâm out of ideas. The professor wants us to summarize the introduction, and summarize what you will do in each section of the experiment and state how this work will support the goal of this experiment being longer than 1/2 a page. Please, please help me right a better purpose for the experiment below. Thanks.

Experiment 9 Molecular Weight Determination of a Pure Substance Using the Ideal Gas Equation.

Introduction:

The purpose of this experiment is to determine the molecular weight of a volatile, essentially non-polar liquid. An excess amount of pure unknown volatile liquid will be placed into a flask, whose volume will also be determined. The flask will be placed into a hot water bath, whose temperature corresponds to the temperature of the gas in the flask. The liquid will evaporate, driving out the air while the excess liquid evaporates. The pressure of the gas in the flask will correspond to the atmospheric pressure. After the excess unknown liquid has been allowed to evaporate, the flask will be stoppered, cooled, and weighed to determine the grams of the unknown liquid that will be present at the temperature of the water bath as a gas. In this experiment the ideal gas equation will be used PV = nRT = (g/M)RT where R = 0.0821 L*atm/mol*K, T = temperature in K, P = pressure in atm, V = volume in liters, n = moles of gas, g = grams of gas, and M = molecular weight of gas (in units of g/mole). Solving for the molecular weight, M: M = gRT/ PV.

If the molecular weight of a gas is to be determined, the m, T, P, and V must be determined experimentally in the lab. Even though the ideal gas equation is only an approximation of the behavior of gases, molecular weights can still be obtained within 5% of the correct values, as long as volatile non-polar compounds or compounds with only slight amount of polarity are used. For example, C, H, compounds as CH₄ are essentially non-polar, whereas compounds as H₂O are highly polar. Hence, the ideal gas equation would not be a good approximation for describing the behavior of gaseous water.

Procedure:

At the very beginning of the period get a one-liter beaker. Put about 800 mL (your instructor will tell you the exact amount needed) of tap water into the one-liter beaker. Put the one-liter beaker with water onto the hot plate. Set the heat setting of the hot plate to the maximum value. The water in the beaker should be boiling very lightly prior to doing the actual experiment. Therefore, after the water starts boiling in the hot water bath, it may be necessary to cut the heat setting back from highest value. This will take some time. While the water is heating, get the rest of the things needed for this experiment. The setup is shown in figure 1. Record the barometric pressure (in torr to one decimal place). Obtain the rest of the setup consisting of a 250 ml flask, properly prepared rubber stopper with glass tube and aluminum foil, a no-hole rubber stopper, thermometer, and glass stirring rod.

Make sure the 250 mL Florence (or Erlenmeyer) flask is dried (if it is not dry, rinse with 5 mL of acetone, pour off the acetone into the waste bottle in the hood, and then clamp the 250 mL Florence flask onto the ring stand in the inverted position to allow the last traces of acetone to drain out and evaporate. Place the dry no-hole stopper on the flask and weight the flask with the rubber stopper on the balance to 3 decimal places. Record this weight for the weight of the flask plus rubber stopper and moist air. Place 5 mL with a graduated cylinder of unknown liquid into the flask. Place the one-hole rubber stopper, with tube and aluminum foil in the flask. This one-hole stopper, which contains a glass tube that sticks out on the top by 3 mm and is flush with the bottom of the stopper, is covered with aluminum foil with a hole punched into the bottom where the glass tube is. This one-hole rubber stopper is already prepared for you. Push it down firmly into the flask. Remove it. Do this 2-3 times to smooth out the aluminum foil so that the stopper will go down into the flask as much as possible. Then push the stopper down so that it fits snugly but not too tightly to allow it to be removed while the flask is hot. Clamp the flask about the top lip of the Florence flask. That is, the center of the clamp goes about the rim of the flask. Push the flask as far down into the water bath as possible while holding the end of the clamp with your other hand. It is important to be sure that the water in the water bath is always at least 5 mm above there the bottom of the stopper is in the flask. More water may have to be added as some of the water evaporates during the duration of this experiment. (A beaker with hot water (extra) should be present in the hood. One or two of these beakers of hot water should be enough for everyone.) If the water level is not kept to its proper height, the liquid will condense in the upper part of the flask and the excess liquid will never be removed. Be sure that the aluminum foil on top makes a protective wind breaker for the short glass tube sticking out of the rubber stopper so that condensation does not occur there also. As the liquid evaporates from the flask, mix the water in the water bath occasionally and check to see that the temperature remains constant. Record the temperature value of the water bath as the temperature of the gas in the flask for the temperature of the gas would have equilibrated to the temperature of the water bath. After all the liquid has evaporated (takes 2-5 mins for the liquid to evaporate.) from the flask (check carefully that all of the liquid has evaporated-since observing when all the liquid has been evaporated maybe difficult, you should carefully shake slightly the clamp holding the Florence flask to observe the movement of the unknown liquid and when it has disappeared) and none is condensed on the surface walls; (if condensation occurs, be sure all precautions mentioned above are taken) then (these next several steps are to be done quick) remove the rubber stopper with the glass tubing and aluminum foil without excessive shaking. There could be a condensed liquid droplet or two in the glass tube that is not visible. The droplets could drop back into the flask and cause a false high reading for the measured weight of gas in the flask. Immediately replace the rubber stopper (with the glass tube and aluminum foil) with the no-hole stopper, which was used when the flask was originally weighed. This step must be performed quickly to prevent the unknown gas vapors from escaping and being replaced by moist air. Place the no-hole rubber stopper in the Florence flask firmly. Remove the flask from the bath and again check to be sure that the no-hole rubber stopper is firmly in place. Cool the flask by running tap water over the flask for 30-60 seconds. If the stopper is not fitted firmly, air will enter the flask as the liquid inside the flask condenses. As the gas cools and changes to the liquid state, a partial vacuum is created inside the flask. Hence, air will enter the flask if the rubber stopper is not fitted firmly. Completely dry the flask and weigh it on the balance to three decimal places. Record the weight of flask plus stopper and unknown gas.

Repeat this entire procedure a second time and record the date. After, second trial, completely fill the flask with distilled water. Place the no-hole rubber stopper in the flask allowing the excess water to overflow. Wipe the outside completely dry. Then measure the volume of the water in the flask by pouring water into a graduated cylinder. Record this volume.

Experiment 1: Calculating Rate of Reaction

In this experiment you will calculate the rate of reaction of potassium iodide and hydrogen peroxide. The order of the reaction will also be determined.

Materials:

20 mL 3% Hydrogen peroxide, H₂O₂
15 mL Iodine-Potassium Iodide Solution, IKI (1% Iodine, 2% Potassium Iodide)
100 mL Beaker
10 mL Graduated cylinder
100 mL Graduated cylinder
250 mL Beaker
(2) 250 mL Erlenmeyer flasks
1-Hole Rubber stopper
2-Hole Rubber stopper
(2) 3 in. Rigid tubing pieces
(1) 6 in. Rigid tubing
6 Pipettes

Stopwatch
Permanent marker
Waste beaker (any volume)
*Access to graphing software
*Access to a computer
*24 in. Flexible tubing
*Water
*10 mL Distilled water

* You must provide

*You must cut this piece of tubing into two, 12 inch pieces. (if you have not already done so).

Procedure

Preparation of Apparatus

Set up apparatus as shown in Figure 2. To do this, begin by labeling the Erlenmeyer Flasks as 1 and 2. The reaction will take place in Flask 1.

Fill Flask 2 approximately three quarters of the way full with water.

Press the 2-hole rubber stopper into the top of Flask 2. Place one three in. piece and one six in. piece of rigid tubing into each hole of the rubber stopper. This should create an airtight system.

Place the one-hole stopper on Flask 1, and fit the remaining 3 in. piece of rigid tubing in the stopper hole.

Connect Flask 1 and Flask 2 with the two, 12 in flexible tubing pieces. One piece should connect Flask 1 to Flask 2, and the second piece should connect Flask 2 to the graduated cylinder. The tubing which connects Flask 2 to the graduated cylinder should be positioned low enough to be immersed in the water in Flask 2.

Figure 2: Apparatus set-up. Note this is a sample set-up and is not drawn to scale. Your specific equipment may vary slightly.

Part A: Preparation of Reactants

Pour five mL of the IKI solution into a 10 mL graduated cylinder.

Add five mL of distilled water to the graduated cylinder to bring the total volume to 10 mL. This is the 0.5% - 1.0% (diluted) IKI solution.

Pour 15 mL of 3% H₂O₂ solution into a 100 mL beaker.

Add five mL of distilled water to this beaker and mix with a stir rod. This is the 2.25% (diluted) H₂O₂ solution.

Part B: Performing the Reaction

Remove the stopper from Flask 1 and place five mL of the 3% (undiluted) H2O2 solution and 10 mL of the undiluted IKI solution provided into the flask. Immediately replace the stopper on the flask.
Note: At this point, you should select an extra beaker (any volume) from your lab kit to use as an supplemental collection container beaker for Step 6. You do not need to use the beaker yet, but keep it in close proximity.

Swirl Flask 1 until you observe a steady dripping of water going into the 10 mL graduated cylinder. This could take 3 - 5 minutes. Check for leaks in the tubing or system if water does not start rising up the plastic tubing coming from Flask 2 and traveling towards the graduated cylinder within one minute.

Stop swirling Flask 1 when you notice the steady flow of water droplets. When you stop, the water drop -rate will significantly decrease (to around one drop every 5 - 20 seconds) and could take a few minutes to stabilize. If a steady flow of drops of water does not occur within a few minutes, swirl Flask 1 for 1 more minute and check again. Repeat this process until there is a steady flow of drops of water after you have stopped swirling Flask 1.

Quickly empty liquid that has collected in the 10 mL graduated cylinder and replace the empty cylinder back under the flexible tubing.

Allow the flow of drops to become steady again. This could take 1 - 3 mL of water.

Start timing once the drop rate is steady and the volume of water collected is at a whole number (such as three mL). Record the time in Table 1 each time 2 mL of is water displaced. Continue taking data until you have at least 10 data points (20 mL displaced).
Note: Use the extra beaker (located in Part B: Step 1) to collect additional fluid when the volume of displaced water exceeds 10 mL.

Return the collected water from your 10 mL graduated cylinder to Flask 2. Ensure the seal is air tight.

Empty, clean and dry Flask 1 and the graduated cylinder.

Repeat Steps 1 - 8 for the following trial conditions: 5 mL 3% (undiluted) H₂O₂ mixed with 10 mL of 0.5%-1.0% IKI solution (placed in Flask 1); and, 5 mL of 2.25% H₂O₂ mixed with 10 mL of 1.0%-2.0% IKI solution (placed in Flask 1). Record the data in Table 2 and Table 3, respectively.
Note: Clean the graduated cylinder and extra collection beaker before it is used to measure any additional reagents for Trial 2 or Trial 3; and, before it is used for collecting the water from the reaction in the apparatus.

Use a graphing software program to make a graph of each trial. The graph should demonstrate the relationship formed between time vs. mL of water displaced.

Find and record the slope and the inverse slope for each trial.

Table 1: 10 mL Undiluted (1.0 -2.0%) IKI and 5 mL 3% H₂O₂
mL water displaced	Time (seconds)
2
4
6
6
8
10
12
14
16
18
20
22
Slope:
Inverse Slope:

Table 2: 10 mL Diluted (0.5-1.0% IKI) and 5 mL 3% H₂O₂
mL water displaced	Time (seconds)
2
4
6
6
8
10
12
14
16
18
20
22
Slope:
Inverse Slope:

Table 3: 10 mL Undiluted (1.0 -2.0%) IKI and 5 mL 2.25% H₂O₂
mL water displaced	Time (seconds)
2
4
6
6
8
10
12
14
16
18
20
22
Slope:
Inverse Slope:

Calculations

Post-Lab Questions

1. Determine the order of the KI in this reaction.

2. Determine the order of the H2O2 in this reaction.

3. Calculate the rate law constant.

4. What is the overall rate law?

5. When finding the order of H2O2, why was Trial 1 and Trial 3 used?

6. When finding the order of KI, why was Trial 1 and Trial 2 used?

7. Research and identify some alternative catalysts that could be used to accelerate the decomposition of hydrogen peroxide. Evaluate these catalysts and determine which option is

yeast population dynamics

Procedure

1. Work in pairs on this lab, so 12 tubes per pair of students. And share a tube rack with one other pair of students

2. Turn on your spectrophotometer. It needs at least 15 minutes to warm up to give you good readings.

3. Add 5 mL of yeast extract solution (YECM) to each of 12 tubes. (The yeast extract provides vitamins and amino acids for yeast growth and will be the same for all cultures). The tubes should be labeled with your initials, treatment, and tube number. Tape or Parafilm down the lids of 3 tubes, and label them âCONTROLâ.

Do not touch the insides of the tubes or lids! Try to keep these as sterile as possible!!

4. Add 50 mL live yeast culture to each of the remaining 9 tubes.

5. Add the varying volumes of sugar and/or ethanol using Table 1 below.

6. Use Parafilm to close the tops of each tube, making sure the Parafilm is tight and no air can get in, and label each tube with the following:

Amount of sugar added (mL) Amount of ethanol added (mL)

Name of your group Tube number

Table 1: setup yeast tubes (remember, 1 mL = 1000 mL)
Tube number	Yeast culture medium? (5 mL)	Live yeast culture? (50 mL)	Sugar added (mL)	Ethanol added (mL)
1 â control	YES	NO	0	0
2 â control	YES	NO	0	0
3 - control	YES	NO	0	0
4	YES	YES	0	0
5	YES	YES	0.25	0
6	YES	YES	0.5	0
7	YES	YES	0	0.25
8	YES	YES	0.25	0.25
9	YES	YES	0.5	0.25
10	YES	YES	0	0.5
11	YES	YES	0.25	0.5
12	YES	YES	0.5	0.5

Procedure for measuring absorbance (in absorbance units, or AU)

7. Calibrate the spectrophotometer:

Turn on the spectrophotometer and let it warm up for 15 minutes. You will get erroneous results if you donât let it warm up first.

Be sure the spectrophotometer is set to read at the wavelength of 550 nm

With no tube in the spectrophotometer and the lid closed, use the left-hand knob to adjust the reading to 0% Transmittance/push zero button to calibrate

Insert a CONTROL tube (making sure it is clear, without bacterial contamination which would make it cloudy), and use the right-hand knob to readjust the spectrophotometer to 100% Transmittance.

When reading the absorbance, be sure to line up the needle on the spec with its reflection.

8. Immediately before reading any tube, vortex the tube so that the spinning column reaches the bottom of the tube for several seconds. This is critical! The yeast cells are heavy and will tend to sink to the bottom of the tube, so you must vortex the tubes to resuspend them: otherwise, your spectrophotometer readings will be erroneously low. If the vortex is not enough to suspend the pellet of yeast cells at the base of the tube, take a piece of Parafilm and cover the top of the tube, then cover this with your thumb and shake the tube vigorously. The pellet should dislodge and the yeast cells should be easily resuspended after doing this. Use a Kimwipe to wipe down the outside of each tube, to remove fingerprints and other smudges that could affect the absorbance reading. (COULD BE A POTENTIAL ERROR)

9. Record the absorbance (in absorbance units, AU) for the tube on your data sheet.

10. Repeat steps 5 and 6 for every tube.

11. Leave the spectrophotometer turned on for the next user.

Figures you should include are:

Average absorbance vs. time for the no ethanol (0 mL) treatment

Average absorbance vs. time for the 0.25 mL ethanol treatment

Average absorbance vs. time for the 0.50 mL ethanol treatment

Sugar added vs. average carrying capacity (K). Use different symbols to denote each of the three alcohol concentrations

A. After a limit, the increasing concentration of sugar decreases the carrying capacity and growth rate. This is because at higher sugar concentrations, the medium becomes hypertonic and the yeast cells loss water towards the medium.With increasing concentration of the ethanol, the carrying capacity and the growth rate decreases. Why does this happen?

B. Is there any interaction between the effects of adding sugar and alcohol on yeast?

C. why do some cultures not reach K?

D. What are the potential sources of error and assumptions made in this experiment?

E. What do these results mean in a more general (non-yeast) context?

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PADM 5600 Chapter : Landons Project

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