write 10 comments about one to two sentence for each comment.
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che.zipCHE/1290 Chem Forensics Project Fall16.pdf
rev Fall 2016
Name: _______________________________________ CHEM 1290 Section No. ________
Chemical Forensics II Group Project 100 pts. total – due in lab per the posted Experiment Schedule
50 pts. = online participation; 50 pts. = answers to questions 1-2
This assignment is a group project that requires participation in Blackboard. The discussion about this assignment must take place on the group discussion board, as a reply to the thread “Chem Forensics”. In order to receive the participation points, you must post multiple replies on the Discussion Board that contribute constructively to the discussion; “I don’t understand the assignment”, “I agree” or similar postings will not receive any points. A minimum of ten original, constructive and valid posts is required to receive full credit for the online portion of the assignment. Proper use of the vocabulary you have learned in lab (precipitate, supernate, filtrate, etc.) is a requirement of the assignment; points will be deducted for improper use of this vocabulary. Each lab section is a group and all of the information needed to complete the assignment has already been or will be covered in lab and/or your lab manual. Although this is a group assignment, each student must turn in, as a minimum, the written answers to the questions below in order to receive credit for any part of this assignment. The assignment is due at the beginning of lab on the day of your last experiment for the semester – see the posted Experiment Schedule to confirm the date.
Note: Read the entire problem and make sure to follow ALL directions for each question. Scenario: You are an engineer supervising the work on a brownfield remediation project. Just before the
close of business, as you are grabbing your coat, you notice one of your coworkers left some stock solutions out on the bench. Thinking you can quickly put them away and then go home, you walk over to do so, but you discover instead that the labels have not been put on the stock containers. There are labels on the counter, in front of the containers, but they have not been printed yet. There are four colorless glass containers, two of which contain a clear, colorless solution. The other two solutions have a dark bluish-green color.
Over to the right are a number of containers that had been used recently. These containers
contain chemical compounds, in solid form, that are commonly used in your lab. They are: barium nitrate, nickel(II) chloride, potassium nitrite, iron(III) nitrate, lithium sulfate, aluminum nitrate, sodium bromide, lead(II) chloride, calcium nitrate and magnesium fluoride.
Can you identify the contents of the containers and put correct labels on the containers? 40 pts. 1. Design a flowchart to show how you would test the solutions to determine what they
might be. The flowchart must clearly list the chemicals needed for each test as well as show the expected test results.
10 pts. 2. If you were actually confronted with this situation, would you put labels on the
containers or would you dispose of the solutions? Explain your answer.
CHE/How To Make Chemistry Flowcharts.pdf
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HOW-TO MAKE A FLOWCHART Dr. John Rentner – University of Toledo “A good flowchart should give a reader an immediate idea of what needs to be done in the laboratory except in a less detailed format. Think of a flowchart as a "road map" of the experiment. It gives a reader a "pictorial" representation of the experimental procedure. In general there are two major steps when constructing the flowchart. First, read the experimental procedure carefully. Second, rewrite the procedures in a flowchart format. Keep in mind that the flowchart should be brief and cover all the steps in a simple and easy to follow manner. There should be no complicated sentences or paragraphs in the flowchart. You may have to do a lot of rewriting in order to simplify the procedures into a flowchart format. This is exactly why we want you to do it. This gives you a chance to THINK about what you read and how to rewrite it in a way that can be implemented into a flowchart.”1 Flowchart Components There is not any one “right” way to make a flowchart of one of our chemistry experiments. In business and industry, standard shaped boxes are used to construct flowcharts, which ensures that another person looking at the flowchart will understand what it means. Chemistry flowcharts generally consist of four different geometrically shaped “boxes”. Terminal box (start or end of the experiment) Processing box (steps in the experiment)
Connector box (a convenient place to join arrows together)
Decision box (makes branches in the experiment where you have to make a decision)
These “boxes” are connected with arrows showing the flow of the experiment. We’ll use these shapes, along with these few rules to construct our flowcharts. (In Chem 1280 and 1290, we are not concerned that you always use correctly shaped boxes, but you should follow the rules listed below.)
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1. Make an explanatory title. Example: LAB 484 – Relating Mass and Volume
2. Flowcharts begin with only one “start” terminal box but you can end with one or
more “end” terminal boxes.
Example:
3. Reagents added during the experiment are NOT shown in boxes.
Example: Adding 3M HCl
Add 10mL 3M HCl
Obtain unknown sample; record sample number
Weigh unknown sample
Gravity filter
Filter sample
Put filtrate down drain
Dry and weigh Residue
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4. Process boxes usually contain actions.
Example: Here’s a complete example using the procedure in Chemistry 1280 lab 484 – Relating Mass and Volume. Here’s the procedure as written in the Lab Manual.2
1. Obtain an unknown from Group 1 from the supply cart. Record its code on the
data sheet.
2. Obtain a 25 mL graduated cylinder from the supply cart. Add approx. 15 mL of
water to the cylinder. Measure and record the volume of water in the cylinder.
3. Place the cylinder on the balance and record its mass.
4. Carefully add enough of the unknown sample to change the volume of water in
the cylinder by approx. 0.5 mL. Measure and record the mass of the cylinder, and
record the new volume of water in the cylinder.
5. Repeat step 4 four more times.
6. Carefully pour off the water from the solid sample in the cylinder. Transfer the
solids to a paper towel so that they can dry while you continue with the second
unknown sample.
7. Obtain a different unknown from the second group from the supply cart and
record its code on the data sheet.
8. Obtain a 50 mL graduated cylinder from the supply cart. Add approx. 25 mL of
water to the cylinder. Measure and record the volume of water in the cylinder.
9. Repeat steps 3-6 with the second unknown so that the volume change is
approximately 1.0 mL
10. Return the dried samples to your instructor. Do NOT return them to the containers
on the supply cart.
Dry over boiling water bath
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Below is a flowchart that graphically represents the procedure using the rules above and illustrating the use of the different shaped boxes. In this procedure, the only reagents we add during the experiment are water and more unknown sample.
1 Wun Chiou (A Former UCLA First-Year Lab Courses Teaching Assistant), 2004.
2 Edith Kippenhan, CHEM 1280 Lab Manual, General Chemistry Lab I, Academic Year 2010-2011, University of Toledo, 2010.
