Weighing Bottle, Evaporating Dish Porcelain, And Crucible

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Lab tools that can be used as a container that is heated that is weighing bottle, evaporating dish porcelain, and crucible. Weighing bottle made of glass with a transparent color. weighing bottle shaped like a small jar with a lid that accompanied. Weighing bottle vary in size among which a diameter of 2 cm, 3 cm, 5 cm, and so on, with a diversified high too among which 2 cm, 3 cm, 4 cm and so on.

Weighing bottle cap also made of glass with a transparent color. Between the weighing bottle body and the lid, there is a section called grinding parts. This section intentionally made rough, so airtight weighing bottle. When closed, no incoming air and no air coming out so that the solids contained in the weighing bottle are not contaminated from or to the outside.

How to use the weighing bottle for weighing is clean the weighing bottle before and after use with water and then with soap, and then brushed with a brush tube, and finally rinsed again with water. Then dried with a tissue. At the time of the process to weigh wear disposable rubber gloves or use a tissue to hold the weighing bottle. This is done because the fat that is on hand will add weight so weighed become inaccurate.

Constant weighing means a container that is weighted to have the same weight when weighed 2 times in a row. Constant weighing is usually performed to determine the levels of a substance called gravimetric method. For example, in the determination of water content in the flour can use weighing bottle is heated in an oven of 100°C so that the water evaporates. and the water content of the flour can be calculated.

How to use the weighing bottle for constant weighing is the weighing bottle weighed with an analytical balance in order to get the weight up to 4 digits behind the comma, for example 2.2345 gram. This is called the first weight. hold the weighing bottle with rubber gloves or tongs or tissue during this process. Then put in a preheated oven at 100°C which has been heat evenly for 1 hour. Then cool outside the oven for 15 minutes, then insert it into a desiccator containing silica gel to draw water.

Desiccator is a thick glass container, a diameter 10 cm at the bottom and a diameter of 15 cm at the top. In the midst of the inner basin desiccator there as a silica gel. Then given a porcelain with small holes. Desiccator has a cover and in the middle of the cover there is a big round button to hold the lid. Include desiccator bodies smeared with vaseline so that the lid body and the cover attached and airtight, but can still be opened by hand easily. How to open and close the slide is pushed desiccator lid horizontal. do not insert weighing bottle from the oven directly into the desiccator while still hot. Heat from the weighing bottle will cause the air to push the lid desiccator out if this impulse. If it is very strong it can cause desiccator lid floating or flying up.

After 30 minutes in the desiccator, download weighing bottle from the desiccator and weigh it again with analytical balance. So we get a second weight. Repeat the process of heating in the oven to be weighed with an analytical balance to obtain the third weight. If the weight of the second and third weight difference is not more than 1%, it has obtained a constant weight of weighing bottle. But if the difference is more than 1%, then repeat this process to obtain the weight of the fourth, fifth, and so on until a constant weight is obtained.

Then weigh the sample flour, for example 1.5676 grams in the constant weighing, this weight called flour weigh, then reheat in a preheated oven at 100°C for 2 hours. Then repeat the process as above until weighing the weighing bottle with analytical balance and weight of flour obtained first. Reheat the flour in the oven for 1 hour and repeat the process until the weight is obtained. If the first weight and the second weight difference is not more than 1%, it has obtained a constant flour weight. But if the difference is more than 1%, then repeat this process until the weight obtained third, fourth, fifth, and so on, until the weight of the flour obtained constant. Calculate the water content of the flour with the formula below:

Flour weight - Constant flour weight        x 100%
Flour weight - Constant weighing bottle

To obtain a constant weight quickly, the thing to do is equate time appropriately at each stage of the process from heating to weighing for each weighing.

Another tool that used to heat the solution is evaporation dish porcelain. The tool is shaped like a bowl and made of white porcelain. Before and after using evaporation dish porcelain, the dish should be washed with water and then with soap and thoroughly with a brush tube. Last washed again with water and dried with a tissue or drained.

How to use the evaporation dish porcelain is, as an example for getting the salt powder from cucl2 solution, download CuCl2 solution of 10 ml, this solution is blue, then insert it into the evaporation dish porcelain. Turn on the bunsen and place the tripod and asbestos board or wire gauze thereon. Adjust the bunsen flame so that the flame produced a little red and blue, then place the evaporation dish porcelain containing the solution. Heat for 5 minutes and then raise the temperature of the fire into a blue flame. Heat for 10 minutes and then raise the temperature again so the fire into 2 layers, blue layers and green layers therein.

Heat the solution until all the water in the solution evaporates, leaving only solids or powders CuCl2. Heating by raising the temperature of the flame gradually, so the salt is not splashing out of evaporating dish porcelain. If the heating directly with a green flame inside a blue flame, then this solution will have a significant increase in temperature so that the energy in the solution will be pushed very strongly, and come out so cause splashes.

The next tool to use to heat a substance that is a crucible. This crucible shaped like a small cup with a lid that is the bottom diameter smaller than the diameter on top of it. Porcelain saucer made of white crucible. In crucible lids are small arch semicircles, which is useful as an ear to pick up the crucible lid.

Crucible can be heated over a bunsen flame directly or within the furnace that reaches a temperature of 1200°C. A crucible is usually used to determine the ash content of a substance with gravimetry method. Combustion ash is the residue of a substance that cannot longer be burned. ash usually contain only inorganic substances such as metals or other.

How to use a crucible for constant weighing is weighing crucible with an analytical balance in order to get the weight up to 4 digits behind the comma, for example 6.6345 gram. This is called the first weight. Hold a porcelain cup with a tongs during this process. Then turn on the bunsen and place a the clay triangle above tripod (as shown above). Place a crucible with lid on fire for 1 hour. Then chill on the clean table for 15 minutes, then insert it into a desiccator containing silica gel for 30 minutes.

Then take a crucible from the desiccator and weigh it again with analytical balance. So we get a second weight. Repeat the above process of heating up bunsen weighed in an analytical balance to obtain the third weight. If the weight of the second and third weight difference is not more than 1%, it has obtained a constant weight crucible. But if the difference is more than 1%, then repeat this process to obtain the weight of the fourth, fifth, and so on until a constant weight is obtained.

Then weighing 1.1346 gram sample of flour, for example, is called the flour weight, then heat over a bunsen with a small blue flame so that it becomes charcoal. then raise the fire into 2 layers (blue and green layer) and reheat to ashes. Then repeat the process until the weighing with analytical balance and weight of ash obtained first. Reheat over a bunsen for 1 hour and repeat the process until the second weight is obtained. if the first weight and the second weight difference is not more than 1%, it has obtained a constant weight of the ash. But if the difference is more than 1%, then repeat this process until the weight obtained third, fourth, fifth, and so on until the weight of ash obtained constant. Calculate the ash content of the flour with the formula below :

Ash constant weight – Crucible constant weight  x 100%
Flour weight – Crucible constant weight

That's part of the tools used to heat a substance in accordance with their respective functions.

The Balance

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Balance or scale is a tool used to measure the mass or weight of a substance. Balance in the lab is used to measure or weigh solids, can be in powder form, powder, pellets, rocks, and others. Rarely balance is used for measuring liquids, although occasionally occur. Balance is very sensitive to outside influences such as wind. Therefore, the balance in the lab by a special glass box which keeps the movement from the outside. Only the front of the glass that opened and closed at the time of weighing. Balance is also placed in a special room that is space stations. The room contained only weigh the balance sheet, table and chairs. No chemicals are stored in the space stations. This is done to prevent fro making chemicals.

Balance must be maintained in order to remain cleanliness and accurate so can be used in the long term. Before you begin to weigh and after weighing, the balance to be cleared. Do not let any residual matter that weighed littering the balance sheet or left on the sidelines or at the bottom of the balance sheet.  The cleanliness table balance must also be maintained. Do not let any chemicals or glassware are stored in the balance sheet table. On the table there is only balance. Tables must be flat and solid. Table balance should not be skewed because it would interfere with the performance of the balance and weighed substances that would not be accurate. At each balance accompanied by waterpass to check balance flatness. Balance sloping unusable because the results will not be accurate. Waterpass placed on the back or the front, on the left or right or middle.

Waterpass circular adjoining existing circle line. In the line of the circle there are air bubbles. These bubbles should exist in the midst of a circle to indicate the line of the flat sheet. If bubbles exist alongside it must be moved to the center by turning the feet on the balance glass box. Walking the balance could come down and go up to make the balance in a flat position, although slightly tilted the balance table. If bubbles are left in the water pass means that the balance sheet is too heavy or tilted to the left, which smoothed the way lower right leg balance by rotating the knob so flat. Space under the counter balance must be empty, so that people who weigh can put his feet and feel comfortable and concentrated during weighing. People who weigh should not talk or breathe too hard. Because of the wind in the mouth will affect the balance sheet. Seats for weighing wheeled should not, but it should stay in place and sturdiness.

Balance in the lab there are various types, depending on how accurate the substance to be weighed. The types of balance are Analytical Balance and Technical Balance. Analytical balance was used to measure very accurately the solids are up to 4 digits behind the comma, for example 0.1234 grams. Analytical balance has a very small tolerance limit is 0.1%. There are 2 types of Analytical balance which is non-digital and digital Balance. Analytical balance non-digital need of stone weighing scales to weigh a substance.

Weigh stone made of metal that weighs already calibrated and equipment used for weighing. Weigh stone has various sizes 1 mg; 2 mg; 5 mg; 10 mg; 20 mg; 50 mg; 100 mg; 200 mg; 500 mg; 1 g; 2 g; 5 g; 10 g; 20 g; and earrings. Weigh stone shaped round tube, on the top of the basin-shaped and small spheres to take the stone weigh. Earrings are metal shaped like a curved wire, shaped like earrings that can be pinned on a balance scale so-called earring. A set of stone weighing stored in a sealed box to prevent contamination. To pick up a stone weighing, use tweezers clamp. Tweezers are shaped like tweezers to pull their eyebrows on women's cosmetic equipment. Stone weighs should not be taken by hand, because the oil is in the hands can be attached to a stone weighing and adding to the weight of stone weighing.  This will cause the weighing to be inaccurate. Before and after using the stone weighed, every stone that was taken out of the box should be wiped using a tissue. This is done to keep the stones weigh. Stone weighing must be calibrated periodically to maintain weighing accuracy.

On the analytical balance of non-digital, there are two cups, as a place to put the stones weigh and another to put the substance to be weighed. And among the bowls are clockwise to move to the left and to the right. Amidst the needle there is a middle line which marks the middle of the balance that is the scale of zero (0). This analytical balance is locked by turning a knob that can cause the needle to weigh stop and not move. The needle could have been stopped in the left or the right, does not fit in the number 0. But if the balance is turned on, the needle will move to the right and to the left. At the top of the needle there is a scale like a ruler. Length up to 10 to the right and -10 to the left of the number 0 as the clock antiquity. One cup on the analytical balance serves as a container for solids will be weighed and the cup the other as a stone weighing. The principle of analytical balance non-digital is very simple in terms of balance between the heavy stones weighed with the weight solids to be weighed. Heavy stones weighed already known with certainty that the weight of solids can be known.

How to weigh the analytical balance of non-digital is prepared chemicals that will be weighed, a small spoon or a spatula, stone weighed, weighing bottle, tissue or blotting paper, and brushes. Weighing bottle is a glass tool in the form of a small glass tube that has a lid, shaped like a small jar. Bring all the tools and the material was in one container to space stations. Before weighing makes sure the waterpass in the flat state (position of the bubble in the middle). Go to the front of the glass cover. Clean the balance with a brass cup. Turn on the balance by turning the knob. Wait needle stops moving on a scale of zero (0). Place the weighing bottle in the cup right balance in the position of the lid open. Take a weighing bottle with a tissue and wipe the outside with a tissue first. Take the stone weigh sufficiently with tweezers and put it on the left cup of the balance sheet. Wait until the needle stops on scaled zero (0). If the needle stops in the right scale of 0 means the stones weigh placed on the left cup is too heavy, we must reduce them. If the needle is at the left scale of 0 then the stones weigh too light so we had to add to it.

Time for the needle to stop moving can be up to 3 minutes. Do not let any distractions that could move the needle from the outside so it is important to close the front glass. For example, to weigh the empty weighing bottle requires a stone weighing 4.3456 grams. And we want to weigh as much as 1.2345 grams solids. Then add the number of stones needed to weigh the weighing bottle with the solids to be weighed, IE 4.3456 grams + 1.2345 grams = 5.5801 grams. The tolerance limits of deviation is 0.1%. Take the stone that weighs as much as 5.5801 grams stone weighing 5 grams; 0.5 grams; 0.05 grams; 0.02 grams; 0.01 grams; and 0.0001 grams then place all the stones weigh left earlier in the cup of the balance sheet by using tweezers. Wipe each stone weighing with a tissue. Enter solids into the jar weigh little by little, not to get chemicals that fall outside the cup (outside the weighing bottle) because it would create inaccurate weight and balance front glass lid. Wait needle stops moving and is on a scale of 0. If the needle stops in the left scale of 0 means chemicals in bottles weigh too much and we have to reduce it.

If the needle stopped on the right balance point means chemicals in bottles weigh too little and we have to add to it. The time needed for the needle stopped about 5 minutes. When closing the front glass sheet should slowly so that the needle quickly stopped. When the needle stops on a scale of 0 means the chemicals that we weigh is appropriate as we need and we have finished weighing. Analysis of key balance sheet back so that the needle stops. It is very important to keep the sensitivity of the balance sheet. Take a weighing bottle carefully and cover with lid weighing bottle. This time should not use tissue because it has been completed weighing. Return the stone weigh into the box by using tweezers. Wipe each stone weighing with a tissue before it goes into the box. Clean the balance with a brush. Close the back windshield of the balance sheet. Bring all of the chemicals and equipment from space stations, lest forgotten.

Other balances in the lab are a technical balance. This balance can measure the weight of solids up to 2 decimal places. This balance can weigh up to 611 grams. This balance is used to make solvents or reagents of solids, then add with solvents such as water, alcohol or other solvents. Technical balance less sensitivity if compared to the analytical balance. The technical balance does not need stone for stone weighing scales have been installed in the balance sheet and cannot be removed from the balance sheet. This balance sheet only has one cup to put the container solids. The containers can be used to weigh 100ml beaker and watch glass as a cover. At the top there are three technical balance scale like a ruler to scale smallest to largest. In the first scale to weigh on the left there is a stone weighing one gram can be shifted from a scale of 1 to 10. The second scale is there are stones weigh weighing 10 grams that can be shifted from scale 10 to 100gr. And the third is there are stone Scale weighing weighing 100 grams that can be shifted from a scale of 100 to 500gr. At the right end of the scale there are three lines that signify balance balance balance sheet. This line must be parallel to the balance point on the balance sheet.

The working principle of balance between the technical balance weighs stones contained in balance with the weight of chemicals that will be weighed. Stone weighing scales is known for certain that the weight of solids can be known with certainty. To signify the balance sheet in the flat state, the line at the end of the scale should be proportional to the balance point line. The technical balance doesn't need a special room, glass to withstand the wind because the balance of sensitivity is lower when compared to the analytical balance. Before and after using the balance, the balance should be cleaned with a brush and tissue. Only part of the cup is cleaned.

How to use the technical balance that is placed beaker and watch glass on a saucer in the balance sheet. Then slide the stone weighed on a scale of 10 to 100 grams. For example on a scale of 30 grams, the line at the bottom end of the scale exceeds the balance points mean stones weigh heavier then slide it back toward the stone weighing 20 grams scale. If the upper end of the scale to exceed the balance of points, then slide the stone weighed on a scale of 1 to 10 grams. For example on a scale of 4 grams, the bottom end of the scale exceeds the balance points, then return the stone to weigh on a scale of 3 grams. Movement on this scale to tip the scale in parallel with the balance points. End of the scale to move up and down until it eventually stops. If the end of the scale is aligned with the balance points mean we've got the weight of the beaker and watch glass. For example the scale indicates the number 46. This means that we get the weight is 23.46 grams.

Suppose we want to weigh as much as 5.15 grams solids. Then add the weight of the beaker and watch glass with the weight of the desired chemicals, namely 23.46 grams plus 5.15 grams, the result is 28.61 grams. After that the sliding stone weighing second scale to number 20 then the third scale to 8 and 61. Then enter the solids to be weighed into a beaker and cover again with a watch glass. When opening or closing the cover glass can directly use our hands or wear disposable rubber gloves, do not need to use a tissue. Add solid little semi little to tip the scale in parallel to the balance point. If the end of the scale below the balance point meant solids put into the beaker excessive and should be reduced. And if it ends above the balance point scale means a chemical that is added is still lacking and need to be added again.

The balance of the most modern and widely used today is digital balance. The digital balance is very easy to use because we all need is to see the number on the monitor balance to determine the weight of the solids that we weigh. Digital balance as balance to measure people weight, only smaller. There are 2 types of digital balance, there are analytical and technical. The analytical balance can measure up to 4 digits behind the comma as 3.1234 grams and technical balance can measure solids up to 2 decimal places such as 3.12 grams. In the digital balance there is waterpass to indicate a flat surface. If the surface is not flat, the balance cannot be used. Just as the balance of non-digital if no air bubbles in the water pass amid the increase or decrease one leg balance sheet so that the bubbles move to the center.

Digital Balance analysis has a special room to keep the glass from outside influences while technical digital balance is not protected by the glass. Digital Balance should be cleaned before and finished weighing. And cleaned in a state does not turn on or off. At the time cleared the most important component to be cleaned is the cup. This cup can be opened so that it can be cleaned up to the inside. Use a brush or a tissue to clean it. In the digital balance there is a button on and off to switch on and off the balance sheet. There is also a reset button to make a balance sheet to 0.0000 grams, although there glassware or chemicals above on it. Program button is used to select the type of program that is on the balance sheet. Digital balance sheet has only one cup and saucer is under a monitor that shows the number or weight of substance weighed. Another button is the button memory to record the weighing results. There is also a balance sheet that is accompanied by a printer that can print the results of the scales.

How to use the digital analytical balance is cleaned with a brush or a tissue, turn on the balance sheet, open the windshield or side of the balance sheet and then enter the weighing bottle Lid. On the monitor will display the weight of weighing bottle, note if necessary. Then press the reset button on the monitor screen will appear 0.0000 grams. Go to the windshield or side of the balance sheet and enter the chemicals that will be weighed into a weighing bottle and put a lid of weighing bottle. To open the bottle cap can weigh and use your left hand to insert substances into the weighing bottle can use your right hand. Or vice versa. Right and left side glass can be opened and closed. After getting the desired amount of weight, cover with the lid and weigh the bottle and also all the glass lid on the box the balance sheet. Please note the weighing results or print via a printer. After completion of use turn off the balance by pressing the keys off and cleaned again with a brush or tissue.

How to use technical digital balance is cleaning the cup of the balance with a brush or tissue. Then turn on the balance. Place beaker glass to weigh with a glass lid. Record the weight that appears when necessary. Then press the reset button and on the screen will appear 0,00 grams. Enter the solids to be weighed into a beaker and cover again with a cover glass. After getting the desired weight, take a covered glass and beaker then turn off the balance by pressing the off button. Cleaned the balance with a brush or tissue.

Calibration is a way to maintain the accuracy and appropriateness of the balance. Calibration is performed periodically, for example, once a month. Then the results are recorded and reported. How does the calibration on the balance of non-digital or digital balance, or analytical balance or technical balance, just the same. IE by weighing the stones weighing standards known with certainty and fixed. Tolerance for severe irregularities each stone weighing at 0.1%. Weigh stone used for calibration must be more than 5 stones to weigh the different weights. Stone is starting to weigh weighed from the smallest to the largest. Before and after the use of stone weighing should be cleaned with a tissue. To retrieve the stones used weigh clamp tweezers. After completion of the stone weighing weigh, calculate the calibration results. In the digital balance is no program to calibrate the balance sheet, press the button and select the calibration program, and then follow the steps indicated on the monitor. After completion of the calibration, the balance will automatically calculate the measured deviation. And print the results of the calibration.