6. After use, where should latex gloves and paper towels be disposed? Solid wast

Question

6. After use, where should latex gloves and paper towels be disposed? Solid waste chemicals? Liquid waste chemicals? Broken glassware? 7. A concentrated acid is to be diluted with water. Should the water be added to the acid or should the acid be added to the water? Why? stiring babusesc dongeran splq ering 8. A 5-ml portion of a chemical is needed but you accidentally dispense 20 mL of the chemical into a beaker, Should the excess chemical be poured back into the reagent bottle? Why or why not? Heating of a chemical is carried out in an open test tube. Where should you point the mouth of the test tube? 9. Our nei ghbur r ourselves 10. In the middle of your experiment, the fire alarm sounds. What should you do? You are the first one finished with the experiment so you remove your goggles and apron but remain in the laboratory room to answer the post-laboratory questions. Is this safe? Why or why II. not? A concentrated acid is contained within a carboy (large bottle used to hold corrosive liquids) that is capped with a pump for dispensing the acid. Is it safe to dispense the concentrated acid into a small test tube? A small beaker? Why or why not? 12. 13. In the middle of your experiment, you must use the bathroom. Should you remove your latex gloves before exiting the laboratory room? Yes sChemistry 116

Explanation / Answer

Ans. #6. The latex gloves and paper towel are non-glass solid material. So, they shall be disposed as solid waste chemicals into the specified bin.

#7. Acid shall gradually be added to water.

Solvation of acid in water is an exothermic reaction. If water is added to acid, the whole amount of acid reacts with water (protonation) to generate large amount of heat of solvation at once. The resultant sudden increase in temperature of glassware may cause its breakage and spillage of its contents.

So, in practice, small quantity of the acid is gradually added to water taken in a suitable glassware (and simultaneously immersing the bottom of glassware in ice cold water). Addition of small amount of acid to water generates small amount of heat which is gradually dissipated from glassware to surrounding. Therefore, there is NO sudden increase in temperature of glassware while making the solution. It thus eliminates the possibility of breakage of glassware from sudden heat shock.

#8. No.    

The beaker may be contaminated with chemicals or water or dust, etc. So, pouring back the excess chemical from beaker back into reagent bottle may contaminate the whole content of the reagent bottle.

#9. The mouth of test tube must be pointed away from yourself or anyone else. It must be noted that the mouth must not be pointed to any individual or chemical or instruments, etc. because the bumping during boiling may expel contents from test tube to the place where its mouth points.

#10. You should do the following things-

I. Stop you experiment immediately.

II. Put off the flame, if any is being used in your experiment.

III. Alarm the other students and individuals in lab. Notify to your instructor, if available.

IV. If you are trained and fire is small and manageable, try to extinguish the fire using suitable fire extinguisher. If you are not trained, or fire is large, leave it as such.

V. See if you can prevent any precious equipment or material from getting damaged by fire. See if you can remove any nearby combustible or explosive material from coming in contact with fire.

Vi. Proceed to the exit gate carefully.

#11. No. Some harmful gases may be released during the experiment. The ventilation system takes some time to remove the toxic gases/vapor from lab to a safer limit.

So, if you have completed the experiment, leave the laboratory to do post-lab questions.

#12. It depends. Nowadays, the chemical dispenser (carboy fitted with pump) are quite efficient in delivering any volume in their range.

For example, a chemical dispense of 1-10 mL can easily and efficiently transfer 5.0 mL acid to a small test tube (10-mL capacity or 5-mL capacity) without any spillage. The same is true for small beaker.   

#13. Yes.

The gloves may be contaminated with chemicals during experiment. So, they must be removed before leaving the lab or touching clothes and skin, etc. to eliminate the chances of chemical contamination and damage to clothes and skin.

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