Laboratory Write-Ups

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Ch100: Fundamentals for Chemistry

Instructor: Tony Zable

1

Emergency: Dial x4444

Ch 100: Fundamentals for Chemistry Laboratory

The laboratory portion of the Ch 100 course represents 30% of the total class grade. Each week you will be given an experimental exercise worth a total of 10 points each. You are required to complete 8 of the 9 assignments for the term. The laboratory work will evaluated based on the following criteria:

A. Weekly Lab Assignments: (5 pts)

Satisfactory completion of a lab assignment will include:

1.

Completion of all experimental procedures

2.

Completed data table(s)

3.

Appropriate analysis of experimental data

4.

Thoughtful answers to all questions posed in the experiment packet.

When appropriate, it is expected that all preliminary questions will be completed (or at least attempted) before the lab session begins. Each completed lab assignment is due at the beginning of the lab period 1 week after the exercise is performed.

B. Laboratory Summary (Write-up) Format: (5 pts)

In addition to the satisfactory completion of the in-class lab exercise, a one-to-two page typewritten summary sheet is required to be turned in with each completed experiment

(stapled to the front of the lab packet). The summary sheet should contain the following elements:

I.

Title of the Experiment

II.

Statement of Purpose/Objective

 1 or 2 sentences describing the ultimate goal(s) of the experiment/exercise

III.

Concept Theory

 Description of the chemical or physical model (theory) to be tested or utilized in the experiment. This section will also hold the underlying equations used to obtain your final results.

IV.

Result(s)

 The final result(s) obtained from the experiment. This section should be very short but should include estimation of experimental error/uncertainty.

V.

Summary Paragraph (containing concluding remarks)

Describe what you learned from the experiment

Include appropriate procedural comments as well as explanation and justification of experimental error.

Discussion of graphs, etc.

Discuss concepts that may still confuse you after the experiment was completed

PCC Cascade Campus

Ch100: Fundamentals for Chemistry

Instructor: Tony Zable

Notes:

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Emergency: Dial x4444

1.

2.

Completed lab packets and write-ups are due at the beginning of each lab session (one week after performing assignment in class).

Attendance in labs is mandatory. You are allowed to miss one lab without penalty.

Additional lab absences will lower your lab score.

3.

Please review “Lab Safety & Etiquette” rules on the following page

4.

Late assignments will be subject to a late penalty, minus 1 point for every week the assignment is late (up to 3 points)

5.

8 of 9 labs will be graded. The additional lab assignment may be turned in for extra credit. The extra lab will be worth up to ½ the value of a required lab.

6.

Missing lab assignments cannot be made up without approval from the lab instructor.

7.

Bring a lab notebook to lab sessions. Record all data and notes during lab experiment in the lab notebook before filling out your lab packet (in case you need to retake some of your data or recalculate a value). The instructor will not accept a sloppy lab packet.

8.

All lab material is “fair game” for in-class exams, even if lab packets have not been handed back. Be sure you keep adequate lab notes in your lab notebook.

PCC Cascade Campus

Ch100: Fundamentals for Chemistry

Instructor: Tony Zable

3

Emergency: Dial x4444

Lab Safety & Etiquette

Safety is of utmost importance. When you are working in the laboratory, please observe the following rules:

1.

Obtain a pair of department approved safety eyewear, and wear them at all times.

Eyes are irreplaceable!!

2.

Know the location of the fire extinguishers, fire blankets, showers, and eyewash stations. Accidents are usually minor, but it is always wise to be prepared for serious trouble.

3.

Be familiar with the escape route in case there is a fire alarm.

4.

Always check the label on the bottle before using a chemical reagent. If you use the wrong reagent, you may have a serious explosion.

5.

Perform experiments that generate an objectionable gas under a fume hood.

6.

Never use chipped, cracked or broken glassware.

7.

When inserting glass tubing into a cork, make sure that the end of the tubing has been fire polished and that lubricant is used.

8.

Do not pick up hot objects with your fingers. Allow heated glass sufficient to cool.

9.

When diluting an acid, pour the acid slowly into the water. Never add the water to the acid.

10.

Do not perform any unauthorized experiment. If you have an idea for improving an experiment or for a new experiment, consult your instructor.

11.

Never point the opening of a heated test tube at another person.

12.

Report all injuries to your instructor.

13.

Do not take reagent bottles to your lab bench for your personal use. Pour the approximate amount you need from the bottle into a small container, and carry this back to your desk.

14.

Never put excess reagent back into the original bottle. There is always a chance of error and subsequent contamination of the original reagent. If you do not know how to dispose of the chemical, ask your instructor for instructions.

15.

Never weigh reagents or chemicals directly on a balance or scale. First, weigh an empty container or zero the container. Then add your reagent to it and reweigh.

16.

Dispose waste into designated containers when directed to do so.

17.

Be sure to wash your hands after each experiment.

18.

Never smell or taste anything in the laboratory unless specifically directed to do so.

Many chemicals are dangerous.

19.

Neither food nor drink is permitted in the laboratory.

20.

Bare feet or open shoes cannot be permitted in the lab.

Failure to observe these rules may be cause for expulsion!

PCC Cascade Campus

Ch100: Fundamentals for Chemistry

Instructor: Tony Zable

4

Emergency: Dial x4444

Sample Lab Write-up

Name: Tony Zable

Class: CH100

Date: 04-01-2004

Title: Separation of Salt & Sand

Objective(s):

1.

To separate soluble and insoluble solids from a salt/sand mixture using filtration.

2.

To ascertain whether or not mass is conserved in the filtration process

Theory: {If there are relevant diagrams, equations & definitions, they would be presented

here!!}

Matter can be classified as either pure or impure. A mixture is an impure substance consisting of a combination of 2 or more distinct substances. A mixture, homogenous or heterogeneous, can be separated into its component substances by physical separation. In contrast, a compound may only be separated into its component substances (elements) by chemical separation techniques.

Filtration is a physical separation that can be utilized to separate soluble and insoluble components within a mixture. This process consists of dissolving the soluble components of the mixture using water then passing the liquid through filter paper. In this way, the dissolved solids are separated from the insoluble solids which are trapped by the filter paper.

In this lab, there were no relevant equations to detail.

Results:

{If there were numerical final results, they would be presented here!!}

Following the addition of water and subsequent filtration, a white crystalline residue was separated from the salt/sand mixture. No attempt was made to identify the crystalline solid nor was the residue weighed to determine its quantity. There were no quantitative results.

Summary:

Using filtration, a crystalline solid residue was extracted from a salt/sand mixture. The white residue, presumably salt, was identified by subsequent evaporation of the liquid filtrate indicating that it was soluble in water and able to pass through the filter whereas the sand pellet left behind in the filter was insoluble and thus not able to pass through the filter.

This separation process is not unlike the filtration utilized by drip coffee makers in the preparation of the coffee beverage. The fact that this process was able to separate a substantial quantity of soluble solid from the original sample indicates that indeed it was a mixture and not a pure compound or element.

Further investigation would be necessary to determine whether the mass of the remaining pellet(sand) and the separated residue are equal to the initial mass of the mixture. To accomplish this, the sand pellet would need to be dried out. To remove the excess water, and weighed using a gram scale. The mass of white (salt) residue could determined by weighing the evaporation dish and residue together, then rinsing out the residue and reweighing the dish. Subtracting the combined mass of the dish and residue from the evaporation dish alone would yield the mass of the residue. Addition of the masses of the separated pellet and residue could then be compared to the initial mass of the mixture to ascertain whether mass was gained or lost during this procedure.

PCC Cascade Campus

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