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Jumat, 27 April 2012

Equipment in Chemical Laboratory

A. Basic Techniques in the Laboratory
1. How to heat the liquid
Should pay attention to the possibility of bumping. How to prevent it by adding a boiling stone into the beaker.
a. Heating the liquid in the tube
o Do not direct the reaction to the mouth tube practican either yourself or others
o Pinch tube at the part near the mouth of the tube
o The position of the tube while heating the liquid at a slight angle, stirring and occasionally shaken
o Agitation continued shortly after heating
b. Heating the liquid in the beaker and the Erlenmeyer flask
The bottom can be in direct contact with the fire while the liquid is shaken gently, occasionally lifted when boiling.

2. How to read the volume in a measuring cup
Enter the liquid to be measured with a pipette and then drops to Ensure your desired scale. The most important part in reading the scale on the measuring cup is the tangent line must match the scale of the liquid meniscus. Meniscus is the curved lines of the liquid surface due to cohesion or adhesion force with liquid measuring cup.

3. How to use a burette
Before use, the buret should be rinsed with a solution that will be used. How to fill it:
Faucet is closed then the solution is inserted from the top using a glass funnel. Do not fill the burette with the top position is higher than our eyes. Lower the burette and statif to the floor so that if there is a solution spilled from the funnel is not splashed into the eyes. Do not let any bubbles left in the bottom of the burette. If there is no bubble, close the faucets. Burette until the next content exceeds the scale of zero, then open the faucet a bit to set the liquid on a scale of zero to be exact.

4. How to use an analytical balance
• Zeroed first balance sheet
• Place the substance to be weighed in the scales
• Read the value stated on the balance of the monitor screen
• After use, re-balance is zeroed

5. How to smell a substance
Remember : Do not inhale gases or vapors of compounds directly!
Use your hands to shake a little odor of gas samples into the nose.

B. Basic Equipment
1). Chemical glasses (beaker): A tall glass, large-diameter with a scale along the walls. Made of borosilicate glass is resistant to heat to a temperature of 200o C. The size of the tool is there are 50 mL, 100 mL and 2 L.
Function:
• To measure the volume of solution that does not require a high level of accuracy
• Accommodating chemicals
• Heating the liquid
• Media fluid warming

2). Erlenmeyer flask : Diameter of the glass to the top gets smaller scale along the walls. Size ranging from 10 mL to 2 L.
Function:
To save and heating the solution
Accommodating filtrate screening results
Accommodating titrant (the solution is titrated) in the process of titration

3). Measuring cup : A tall glass with a scale along the walls. Made of glass or plastic that are not heat resistant. Size ranging from 10 mL to 2 L.
Function:
To measure the volume of the solution does not require a high level of accuracy within a certain amount

4). Pipette : A tool to take a certain amount of fluid or dose-free. Type:
a) Pipette size : Used to take a certain amount of fluid in the right, the center bubble.
b) Pipette size :  A thin tube with a scale along the walls. Useful for measuring and transferring the solution with a certain volume appropriately.
c) Pipette drops : A small pipe made of plastic or glass with a tapered lower end and upper end covered with rubber. Useful to take a liquid in small droplets scale.

5). Burette : A glass tube lined and has a faucet at the end. Size from 5 and 10 mL (mikroburet) with scale 0.01 mL, and 25 and 50 mL with 0.05 mL scale.
Function:
To remove the solution with a given volume, usually used for titration.

6). Tube : A tube that sometimes comes with a lid. Made of heat resistant borosilicate glass, consisting of various sizes.
Function:
 As a place for reacting chemicals
 To perform chemical reactions on a small scale

7). Watch glass : Made from clear glass, consisting of various sizes in diameter.
Function:
 In closing the beaker while heating the sample
 Place when weighing chemicals
 The place to dry the solids in a desiccator

8). Funnel : Made of plastic or glass heat-resistant and has a shape like a stemmed glass, consisting of a funnel with a long stalk and short. How to use it by putting a filter paper into the funnel.
Function:
To filter the chemical mixture by gravity.

9). The Cup : Made of porcelain and is used to evaporate the solution.

10). Mortar and pestle : Made of porcelain, glass or granite which can be used to destroy chemical and mixing solids.

11). Spatula : A long spoon with a flat upper end, made of stainless steel or aluminum.
Function:
 To take the chemical form of solids
Ø
 Used for stirring the solution
Ø

12). Stir bar : Made of heat resistant glass, used for stirring the liquid in the beaker.

13). Wire netting : Wire that is coated with asbestos, used as a base in the spread of heat from a burner.

14). Leg three : The iron that held the ring and used to hold the wire netting in the heating.

15). Burner : Is used to heat chemicals.

16). Suction ball : Used to help making process fluid. Made of rubber that is accompanied by signs to suck up the liquid (suction), takes in air (aspirate) and empty (empty).

17). Balance sheet analysis : Chemical solids used for weighing.

C. Support Tools
1). Flask : A flask with a long neck and a lid; made of glass and should not be exposed to heat because it can expand. Size from 1 mL to 2 L.
Function:
To create a solution with certain concentration and dilute the solution.
How to use:
Load the solution to be diluted or dissolved solids that will be. Add the liquid used as a solvent until the half-filled pumpkins, then shake flask. Stopper the flask, hold the lid with finger, shake the way pumpkin tossing and turning until a homogeneous solution.

2). Pumpkin round : A flask with a long neck, there is a round base, there is a flat. Made of heat resistant glass at a temperature of 120o-300oC. The size ranging from 250 mL to 2000 mL.
Function:
To heat the solution and save the solution.

3). Buchner funnel : A funnel that is basically a porous section and a large diameter. Made of porcelain, plastic or glass. Useful for filtering the sample to dry faster. How to use it by putting a filter paper whose diameter is equal to the diameter of the funnel.

4). Erlenmeyer Buchner : The diameter of the glass to the top has narrowed, there are small holes that can be connected by hose to a vacuum pump. Made of thick glass that can withstand pressures up to 5 atm. Size ranging from 100 mL to 2 L. Used to accommodate liquid filtration results.
How to use:
Beginning with a Buchner funnel installed in the neck flask, attach a hose connected to a vacuum pump on the protruding parts.

5). Separating funnel : A funnel-top round with filler holes are located on the top, the bottom valve. Made of glass.
Function:
To separate a mixture of solutions that have a different solubility. Usually used in the extraction process.
How to use:
mixture to be separated is inserted through the hole above, the valve is closed. Hold the upper lid, the funnel is held with the left and right hands in a horizontal position, shake that extraction is progressing well. Open the top cover, remove the bottom part of the solution through the valve slowly. Close the valve if the solution is already out of the bottom layer.

6). Desiccator : A two-tiered pot filled material underneath the dryer, with a removable cover which is difficult in the cold because it is coated with Vaseline. There are two kinds desiccator: regular and vacuum desiccator. Vacuum desiccator in the lid there is a valve that can open the lid, which is connected by hose to the pump. Drying material used is silica gel.

Function:
 Place of storing the samples should be free of water
 Dry solids
How to use:
 By opening the desiccator lid by sliding it sideways.
 Place the sample and close the same way.
Description:
Silica gel is still able to absorb water vapor is blue; if the silica gel has turned pink then need to be heated in an oven at 105° C until the blue color.

7). Petri dish : Shaped like a walled beaker very low. Made of heat resistant borosilicate glass. Serves as a container weighing and storing the chemicals, microbiology.

8). Spray bottle : A bottle of high lid made of plastic. Serves as a place to store aquades. How to use it by pressing the body until the water bottle out.

9). Krusibel : Equipped with a small bowl and lid are made of heat resistant porcelain, alumina. Used as a place for the reacting chemicals. At the crucible is still in hot conditions, do not directly subject to water. Sudden temperature changes cause the crucible broke.

10). Leg three crucible : Made from porcelain and work to put krusibel now be heated directly on the fire.

11). Stative : Made of iron or steel which serve to enforce the burette, funnel, glass separating funnel and other equipment used at the time.

12). Manice clamp : Made of iron or aluminum that serves to hold the glassware used in the distillation process. The back was associated with the use of clamps bosshead stative.

13). Bosshead clamp : Made of iron or aluminum that serves to connect the clamp manice stative or funnel holder.

14). Burette clamp : Made of iron or steel to hold the burette used for titration.

15). Mouthpiece holder : Made of iron or steel to hold the funnel or a separating funnel used in the screening process or separation. The back of a stative connected using a clamp bosshead.

16). Tang krusibel : Made of iron or steel to take and bring krusibel.

17). Magnetic Stirrer : Magnets are used to stir the solution.

18). Centrifuges : Serves to precipitate and separate the solids from the solution.
19). Chromatography chamber : Made of glass used in the process of paper chromatography.
20). Spectronic 20 : Used to measure the absorbance of colored solutions in the process of spectrophotometry.

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