03 laboratory orientation

Laboratory Orientation

Some Tips for Performing Laboratory Experiments

• Assemble your laboratory apparatus away from the edge of the lab bench to avoid spills and breakage of glassware.

• Inquisitiveness and creativity in the laboratory are encouraged. However, variations or alterations of the experimental procedure are forbidden unless specified by the instructor. The experimental procedures were adjusted with the safety of the student in mind.


• Electronic entertainment products are strictly forbidden. Cellular phones will only be allowed for image capture. Digital cameras are preferred. A lot of chemicals can cause damage to your electronics.

• Read the labels carefully. Certain chemicals produce explosive reactions when mixed with particular reagents, so the wrong chemical may lead to serious accidents or unexplainable results in your experiments.


• Do not use cracked or chipped glassware. Chemicals might leak through those cracks, leading to spills.

• Never pick up broken glassware with your bare hands, regardless of the size of the pieces. Inform your instructor immediately so it can be cleaned.

• Avoid breaking glassware. You will be asked to replace the broken glassware or pay for it, or you will receive an incomplete. If no one admits breaking the glassware, the whole class will be responsible for replacing the broken glassware.


• Never use reagents from an unmarked container. All chemicals will have proper labels, so if a reagent is unlabeled, it is the incorrect reagent.

• If something is unclear about the experiment, be sure to ask the instructor before the start of the experiment.

• Most chemicals in the laboratory are poisonous. Keep food out of the laboratory as they can absorb chemicals from the air or pick them up from the bench.


• Contact lenses should not be worn in the lab, even if goggles are worn. Contact lenses should be replaced with prescription glasses. A person wearing prescription glasses must also wear safety goggles.

• Closed shoes must be worn. This is to protect your feet from splashes or spills.

• Cosmetics, antibiotics, and moisturizers are not to be applied in the laboratory. They may pick up fumes from the air.

• Female students with long hair must secure their hair.


• Avoid wearing dangling jewelry. Jewelry may absorb chemicals and cause allergic reactions. Be particularly mindful of itching, burning, or any other irritation under or around your jewelry.

• Never smell, taste, or touch a chemical or solution unless specially directed to do so. Poisonous substances are not always labeled as such. Individual allergic or sensitivity responses to chemicals cannot be anticipated. Any special health factors must be brought to the attention of the instructor as soon as possible.


• Report all accidents and injuries to the instructor no matter how trivial they may seem. A written report of any and all accidents that occur in the laboratory may be required.

• If an accident occurs, don’t panic! If a person is injured, provide or seek aid immediately.

• Most chemicals are corrosive. Beware of concentrated acids and ammonia. Treat all chemicals as potentially dangerous. Make it a rule to wash off immediately with plenty of water any chemical spilled on the skin. Do not delay.


• Take extra care in handling dust and powders. If these come into contact with the eyes, wash with water for 15 minutes. Do not rub the eyes.

• Chemical spills over a large part of the body require immediate action. Remove all contaminated clothing, and wash with mild detergent and copious amounts of water only. Use the safety shower. Do not apply any other stuff. The instructor will ask everyone to immediately leave so you could have your privacy.


• For abrasions or cuts, flush the affected area with water. For burns, the affected area should be rubbed with ice, submerged in an ice-water bath, or placed under running water for several minutes to withdraw heat from the burned area. More serious burns require immediate medical attention.

• Never do anything that will lead to the contamination of the reagents. Any trace of impurity in a reagent may result in a number of errors in your analysis of results.

How to Prevent Contamination

• Develop the habit of rinsing droppers and stirring rods immediately after use with soap and water (unless they are for use of the whole class).

• Clean up spills immediately even if it is only water. If the substance is volatile, flammable, or toxic, warn everyone of the spill. Spills are considered waste; please use disposal procedures when cleaning up spills accordingly.

• Wash your hands thoroughly before leaving, especially before eating.

Other Procedures

• Please do not use pencil in filling up data sheets. Pencil may become blurred through time, resulting in loss of data.

• Data sheets will be submitted right after the experiment and will be returned to you the next meeting. Please compile the data sheets to prepare for the practical exam and to submit at the end of the semester. Failure to do so will result in an incomplete.

Grading System for Laboratory

• Laboratory is included in papers and assignments section (20% of your grade).

• Experiments are hard to set-up, so if you miss an experiment, you automatically get zero for the experiment. No make-up experiments will be given.

• If you are late, you will be allowed to perform the experiment. However, in the event that everyone else is finished, you will have to stop your work and submit unfinished data. If you do not have classes after the class is over, you may continue the experiment after class hours.

Grading System for Laboratory• You will not be allowed to perform the experiment if

you are not in proper attire. Proper attire is closed shoes, laboratory gown or apron, safety goggles, and gloves. This means automatic zero for the experiment as well.

• The practical exam is also 20% of your grade and will cover the laboratory portion of the class. Practical exams are hard to set-up, so no make-up exam will be given.

• The format of the practical exam involve several stations. Each station has a set of questions to be answered in a given time limit. Once the time limit is reached, you will move to a different station.

Tips for Today’s Experiment

• Since there are many data to be gathered, the work will be split. You will be divided into teams of two. Each team will do one number in the experiment.

• Once you have done your part of the experiment, record your results, and visit the results of the other teams to look and record data. Please don’t copy from their data sheets.

• At the start of the experiment, everyone must record the colors of the original solutions. Once the experiment starts, and the reagent is used up, it will not be possible to note the color anymore.


• Please add the reagents drop by drop. Some extra reactions may occur when excess reagent is added.

• For those who will be assigned to add additional HCl, NaOH, or NH3, please make sure that all the other people have seen your initial results and recorded the data before adding the additional. Then allow them to record the new data as well.

• There is only one test tube brush to clean the test tubes with soap and water afterwards. To facilitate cleaning, please agitate the solution first before throwing at the respective disposal beakers.


• To record the data: If a precipitate forms, write “precipitate” and the color of the precipitate. If bubbles form, write “gas”. Note also if the colorof the solution changes. If nothing happens, write “no reaction”. In the addition of HCl, NaOH, or NH3, if nothing happens, write “no reaction”. If the precipitate dissolves, write “dissolves”. If a new precipitate forms (precipitate changes color), write “precipitate” and the new color of the precipitate. If bubbles form, write “gas”. Note also if the color of the solution changes.


• It is possible that one reaction may have more than one visible change. (Example: both “gas” and “precipitate”, both “gas” and “dissolves”, etc.)

• If nothing happens after the addition of 10 drops, consider it as “no reaction”.

Education

03 laboratory orientation