Pengurusan Makmal Sains 6

UNIT 6: TECHNIQUE OF STORING

UNIT 6: TECHNIQUE OF STORING CHEMICAL REAGENT AND APPARATUS Concept mapping Organic Metal Rubber Glasswar Plastic Paper Apparatus Chemical Electrical Technique In High ware of vacuum organic parts estoring and waxes

6.1

6.2

Objective 6.1.1

To know how to keep chemical and apparatus in the safe ways

6.1.2

To know the important of technique of storing

6.1.3

To understanding the right procedure to keep the chemical reagent

Introduction All the main services including gas, water and electricity should be available. At least one

large sink should be provided. A good storage will make the apparatus can be used in a long period. To store the prepared bulk solutions, a number of apparatus and a good handling of chemical reagent may safe the money. 6.3 Storing the chemical reagent 63

UNIT 6: TECHNIQUE OF STORING

6.3.1

Alcohol Alcohol may be purchased duty free by teaching, research, and

experimental establishments, by permission of the Ministry of Education. The type of alcohol issue under licence are ethyl alcohol and industrial methylated spirits. Ethyl alcohol is defined by customs as ‘pure spirits for use in art or manufacture where Industrial methylated spirits are unsuitable’. Applications to receive duty-free alcohol are made by the institution concerned on the appropriate form. The purpose for which it is to be used must be stated and other details given. These include the address of the premises on which alcohol will be stored and estimated annual requirement. Requisition books are issued to the approved establishment, and when alcohol is ordered a requisition covering the amount should accompany the order sent to the supplier. When the alcohol is received it is accompanied by an official permit which must be send or handed to a local Excise Officer. In the case of ethyl alcohol the package should not be opened. A stock book must be kept where the spirits are stored, and in it must be recorded all receipt and issues. The book should be available at any time for inspection by the Excise Officer, who may also take account of the amount of spirit in stock. A return of all alcohol used must be made annually on the official form.

6.3.2

Poisons

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Certain items in the chemicals suppliers catalogue are marked to define the schedule of rule, which they are controlled. Substances included in the first schedule of the rules can only be supplied against an order signed by purchaser stating his name and address in full, trade, business or profession, and the purpose for which the article is required. Substances controlled by the Dangerous Drugs Act are also marked and these may only be supplied to a person holding a license or who is otherwise authorized to purchase dangerous drugs.

6.4

Preservation and storage of materials The simple methods of preservation and storage of apparatus, as given in the following

notes, may apply to the dispensing store as well as to the main store. 6.4.1

Chemical Mention has been made of the necessity for the segregation of chemicals which

may be dangerous when stored together. Other chemicals tend to deteriorate with the age or because of their hygroscopic qualities and for the other reasons. A constant check at regular invertals on the condition of stock is, therefore, necessary. The old stock should be used up before the new, and a methodical turnover should be effected. The easiest way to do this is to stamp the date on each bottle as it is received and to place the new stock at the back of the shelves. In teaching establishments it is also advisable to label dangerous chemicals, such as some chlorates, in a distinctive way when they are received so that they do not find

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UNIT 6: TECHNIQUE OF STORING

their way into the laboratories without control. Periodically bottles should be inspected for drooping or faded label and these should be replaced.

6.4.2

Glasses of chemical The chemicals may be grouped into two main categories: inorganic and organic.

If space permits further subdivision into grade of purity such as A.R, M.A.R, and O.A.S grades is desirable as this permit greater speed, efficiency, and accuracy when issue are made. In school laboratories the quantity of A.R grade chemicals is usually limited and provision for separate storage may be somewhat easier. If the various grades are kept together in a common store the practice of separating A.R grade from other lesser purity will not only prevent accidental contamination but will also ensure that costly chemicals are not used for exercises where chemicals of lower purity are suitable. Within their particular classes the bottles must be grouped in such a way that they may quickly located for issue and it is easier to do this for inorganic chemicals than for organic one. i.

Inorganic chemicals These should be arranged under the name of the metal. The shelves should be labeled accordingly. Double compounds such as ammonium nickel sulphate or ferrous ammonium sulphate tend to create some confusion but this can be overcome if the normal method of labeling, as adopted by the usual suppliers of chemicals to the store, is followed, and the chemicals are placed on the sheleves accordingly. In any case such matters are put right by the adoption of the procedure to the lab assistance and by the cross reference and location marks on his index card. The prefix to the 64

UNIT 6: TECHNIQUE OF STORING

name of chemicals, such as di-, tri-, ortho-, and meta-, are ignored for storage purposes and such chemicals are stored in the usual way under name of metal. Tri-ammonium ortho-phosphate, for example, would be stored with the ammonium compounds. Ferrous and ferric, cuprous and cupric salts are stored under iron and copper respectively. ii.

Organic chemicals. Organic substances present much more difficulty. The storage of these chemicals in classes such as alcohols, ethers, and acids may be convenient for the selection of substances for certain for certain class exercises, but the system is not convenient for storage purposes. Organic chemicals should be kept in alphabetical order. In employing this system the prefixes such as o-, m-, and p-, are disgraded. This is also generally done in supplier catalogue so that if the the normal system of the chemical supplier is adopted it simplifies the stores arrangement. This is also helpful when chemicals are being reordered and the suppliers catalogue may be easily related to the items stock held. The stock card are marked with the lettered A to Z and with a letter which corresponds to that on the shelf underwhich the substance is located. A further complication may arise with substances such as sodium benzoate. These may be kept with the inorganic or organic group, whichever suits the lab assistance best, provided they are all treated in the same way. Dangerous poisons should be kept in a strong unglazed cupboard under lock. The key should be held by the storeman and the

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UNIT 6: TECHNIQUE OF STORING

poisons issued on signature only. The complete signature of the recipient, who should be a responsible person, must be recorded in a poisons book kept soley for this purpose.

6.4.3

Apparatus The numerous small items kept in the store necessitate an orderly system. One

system employed is to give each stack an identifying letter and each row of bins within the stack a number. If necessary, each bin may also be given a letter so that B.I.B would indicate that the goods were in stack B, top row, second bin. Other similar systems may be used for locating stock in glass racks, and in this case, pigeon holes in the racks would be numbered or lettered appropriately. The stock card in the alphabetical index is given a similar marking to enable the article to be found. The various methods of storing all the articles of equipment is beyond the scope of various compositions may be helpful. i.

Glassware The size of glass apparatus stored should be standardized as far as possible. These item need careful storage and several standart rule apply. They should not be placed in place too high or mixed with heavy apparatus or metal articles. Tall glass apparatus should be stored at back of the shelves and smaller pieces in the front. Special pieces of glassware, for example Kipps apparatus, are stored as far as possible in their original packing and paper containers, such as are supplied on Emil glassware, should not be removed. This is particularly important if the glass is 64

UNIT 6: TECHNIQUE OF STORING

stacked in bins. Case a lots of glassware kept in main store may be retain in the original boxes lining of drawers for the storage of glassware and devices to prevent materials toppling off shelves, do much to save on glassware expenses. Glassware is stored according to its type and size. All flasks, for instance, should be stored in neighboring bins but separated according to size. Flat-bottom vessel may stand upright but round-bottom vessels should be stored in a bin with high front. Small glassware, such as clock glasses, specimen tube, Petri dishes, and microscopic slides, are best kept in shelf trays. Burettes require a long padded drawer. The glass taps in separating funnels should be preventing by sticking with other funnels by ;’/ means with a fragment tissue placed between the tap and the barrel and the greasing. The tap should be secured by rubber band or they may fall out and become mixed. Cloak glasses, if stacked, need a piece of paper between the interfaces. All expensive glassware, such as special pieces with ground glass joints, should be separately packed in soft wadding or similar materials. Thermometer should be kept in their cardboard cases and stored according their type and range. When glassware return to the dispensing store it should not accepted unless clean and dry.

ii.

Rubber

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UNIT 6: TECHNIQUE OF STORING

Many recommendations have been made for the storage of rubber such as the inflation of black rubber tubing and croking of the ends, dusting with talc, and so on. This particular commodity, however, leaves the stores at such a rate that the preserving treatment given it by the manufacturer is usually sufficient to keep it for the limited periods involved. When space is available, it is advisable to hang rubber tubing in coils on a pegboard and to separate the coils accordating to type and size; alternatively, it may be stored in bins. A manufacturer’s sample chart should be kept for reordering purposes and type of rubber tubing they require. iii.

Plastics Plastics apparatus should be stored away from heat sources. If it is brittle, for example Bakelite, it should not be stored with heavy apparatus

iv.

Paper The general rule for storage of paper are that it should be kept in dry, clean and away from fumes. Filter paper should be according to its grade and size and kept in sealed boxes. If opened, the boxes should always be closed again after used. The expensive grades of paper should be carefully issued to the student ant to the others who may not appreciate the cost of special-quality filter paper.

v.

Metalware All items made from metal should be placed together. Those kept in dispensing stores, and which may been in use in the laboratory, should be repainted occasionally. Clamps, bossheads and the collars of Bunsen 64

UNIT 6: TECHNIQUE OF STORING

burners need oiling periodically. The individual pieces which comprise a set of water bath rings should be wired together when being stored, as should cork borer sets. vi.

Electrical parts Electrical equipment and component should be stored as a group, away from fumes and chemicals. Valves and other delicate items should be wrapped in cotton wool.

vii.

High vacuum greases and waxes High-vacuum greases and waxes should be store at an even temperature in a cool place. Because of the large variety used today for high-vacuum work, the lab assistance should have intimate knowledge of them and be in a position to give advice when necessary on the properties of the materials in his care.

Question 1. Which of the following should be cleared labeled? A. rack and shelves B. specimen C. dangerous chemical D. distilled water 2. Dangerous chemical should be stored under___________. A. cabinet B. shelves C. under lab table 64

UNIT 6: TECHNIQUE OF STORING

D. special cupboard 3. Generally, chemicals may be grouped under two main categories which are_______. A. organic and inorganic B. poisonous and not poisonous C. flammable and not flammable D. acid and alkali 4. All of the following are the prefixes to the names of chemicals except? A. di-

C. ortho-

B. tri-

D. Alfa-

5. Glassware is stored according to ____________. 1. date of buying 2. size 3.

price

4. material 6. Which of the following is the best place where the small glassware should be kept?

A. cupboard

C.

Shelf trays

B. special cupboard

D.

Cabinet

a) A)

7. The tubing is normally delivered in _______m length. A. 1.5

B. 1.6

C. 1.7

D. 1.8

8. All of the following are the metal wares except?

A. tripod stand B. Bunsen burner 63

UNIT 6: TECHNIQUE OF STORING

8. The numerous small items found in the laboratory are usually kept in ___________. a) shelves b) cupboard

c) drawers

d) cabinet

9. Which of the following is the electrical equipment? a) transistor b) lenses

c) beaker

d) conical flask

6.9 Answers 1.c

2.d 3.a 4.d

5.b 6.c 7.a

8.d

9.c

10.a

References Amritage, Philip and Fasemore, Johnson. (1977). Laboratory Safety: A Science Teacher’s Source Book, Heinamann Education Books, London. Chisman, Dennis (1987) Preliminary Issues, Practical Secondary Education: Planning for Cost- Effectiveness in less Developed Countries, Commonwealth Secreteriat, London. Fahkru’l-Razi Ahmadun, Chuah Teong Guan and Mohd Halim Shah. 2005. Safety: Principles & Practices in the Laboratory, Penerbit Universiti Putra Malaysia, Serdang. Hegarty-Hazel, Elizabeth (1990), The Student Laboratory and the Science Curriculum: An Overview, The Student Laboratory and the Science Curriculum, pt.1, pg.3. McGrath, Dennis M. (1978), Some General Considerations, Laboratory Management and Techniques For School and Colleges, Anthonian, Kuala Lumpur-Ipoh-Singapore. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg.6. Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg. 13.

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Woolnough, Brian E. (1991). Setting the scene, Practical Science, pt.1, pg. 14. K. Guy. Laboratory organization and administration. London Butterworths

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