area. Samples being Analytical Balance These are most often found in a laboratory or places where extreme sensitivity is needed for the weighing of items. Instead you should use gloves or pan holders. Used Laboratory Balances for sale with warranties and worldwide shipping We carry both used analytical balances and top-loading balances If you need to save money why not let Analytical Instruments help? Here is one our top loading balances. An analytical or semi analytical balance is a form of scale that measures mass to a high degree of precision. The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The perils using this method are similar to those encountered during a direct transfer to an Erlenmeyer flask. Use containers such as beakers, flasks and weighing bottles. The mass limit of our analytical balances beyond which one receives an error message is 200.0000 grams. lab balance Lab.Equipment as of December 29, 2020 showcases 607 lab balances from 9 industry-leading manufacturers. these brochures go into detail on all aspects of using an analytical balance we your bare fingers. When finished, the operator should close the balance door to prevent dust and dirt from entering the balance. Many professors of Quantitative Analysis do not allow them to be placed in the same room where the analytical balances are kept because students often use them to save time when they ought to be using the analytical balances. High levels of accuracy and precision for best results. models available from Tovatech are among the most sensitive instruments in your Analytical lab balances are the most used balances in a laboratory. First of all, the top loading balances are less precise by a factor of 10 and secondly, air currents around the pan can reduce that precision by as much as another factor of 3 or 4. Five precautions you must take for accurate sample weighing Balances today can be connected to a PC, a data printer, an analytical instrument, or a laboratory robot using serial, parallel, or USB cables. An analytical balance (or lab balance) is a class of balance designed to measure small mass in the sub-milligram range. University and If you want accurate weight measurements of laboratory samples, you need to have the right kind of scales. Typically balances use a force restoration mechanism that when a force is applied (i.e. Hogentogler introduces our new line of full featured, high quality analytical balances. Legal. Types of lab balances we offer Analytical & Semi-micro: Analytical balances are ideal for weighing to the highest degree of precision and accuracy usually up to 4 decimal places. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. The analytical balance is used to measure the mass of objects and chemicals until the 0.0001 gram accurately and precisely. The cap is likewise removed from the weighing bottle. NEWTRY 0.001g Grams High Precision Digital Lab Analytical Balance Lab Scale Electronic Precision Balance Scale 1mg for Laboratories Lab Research Jewelry (220V EU/UK/AU Plug, 50HZ, MAX 500g 0.001g) $469.00 $ 469 . It is important for you to realize with what sort of accuracy these weighings should be made. laboratory. Start defining your balance by knowing readability, capacity and repeatability. Ms. Hupert is ePR Program Manager, Mettler Toledo AG. Prepare the Balance for Weighing. In these cases, the user’s application and weighing environment will generally determine the type of balance required. It goes back to 5000 BC where balances consist of two pans and was used by chemists until the emergence of one-pan balance in 1948 (Sandor, 2017). When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. Learn how to use an analytical balance. sample which remains on the weighing bottle rim may be lost and produce a weighing error. sample being weighed. These balances can measure a variety of substances from a single grain of a chemical solid using a micro balance to the weight of a large beaker on a triple beam balance. Adherence to these rules will, at the same time, prevent damage to the balance. they vary in capacity and readability), bioscience technicians should know the general steps for balance calibration and performance verification. Analytical Balance Accessories. ANALYTICAL BALANCE LAB-300 SERIES Features Applications Labocon LAB-300 Series electronic Analytical Balance offers a high level of weighing accuracy that is ideally suited for weighing small quantities of materials and for specialized laboratory uses of Analytical Balances. spill into the device, then polish it with a dry soft cloth. Operating manuals shipped with analytical balances provide â Do not use the surface on which the balance rests for writing or other tasks, as the balance will react to the slightest vibration or slant. For additional information we direct you to our post on calibration The accuracy and precision of the results are dependent on how reliable the weighing system is. 8.3 CALIBRATION 8.3.1 At least once a year, when balances are moved off of a physical surface, or as deemed necessary, the current user shall check all analytical and electronic balances with standard weights. Have questions or comments? An analytical balance (or lab balance) is a class of balance designed to measure small mass in the sub-milligram range. Preparing the balance for use. Record the date, balance number, and operator name in the Analytical Balance and Pipette Calibration Check Laboratory Notebook. This laboratory experiment aims to familiarize the students on the proper use of the analytical balance, to study the instruction on cleaning these precision instruments. The tried-and-true method of transferring a precisely weighed sample uses "weighing by difference," shown here. accuracy. During the course you will be asked to make a variety of weighings. The use of analytical balances in the laboratory is for industries that require accurate and sensitive measurements.Mass of chemicals and other compounds can be measured, and for density determination or pipette calibration,Measurement of medicines,precise animal â¦ Most analytical balances are equipped with leveling bubbles; vibrations can come from a variety of sources but most likely passing foot traffic in the lab. Moisture, grease and dirt on you fingers will affect the weight of the objects. The advantage of this method is that you have more room for sample addition and the placement of your hands, arms and the transfer spatula is less awkward, but the disadvantage is that you must check the weight of your beaker and sample after each addition; it is not good practice to remove excess sample from the beaker if you add too much. The weighing bottle is tipped back up and tapped gently to make sure all of the substance falls back in the bottle and doesn't remain on the bottle rim. Analytical balances We offer several brands and models to fulfil your needs including internal or external calibration, different draft shields, stability filters or various connections. The difference between the first and second weighings represents the amount transferred. Start Right with Calibration. For more on this see our post on calibrating digital scales introducing the Kern Gnome. For example, you can use an analytical balance to correctly weigh the lab samples. trained technicians authorized by the manufacturer. So how did an MIT Ph.D. end up selling refrigerators? Hence, it’s important to choose a balance that can report the information specified by the laboratory protocols and quality control systems. For many laboratory applications, a balance with a high level of precision is essential for weighing samples. Laboratory Balances and Scales are essential instruments used in regular daily laboratory operations, such as percentage calculations, tablet counting and prescription weighing. Before weighing anything on the analytical balance you must make sure that it is leveled and zeroed. The laboratory balance was born. for an analytical balance is an electrostatic discharge ionizer, especially when weighing grams and The mouth of the beaker is rather high, so one must have good coordination to orient the spatula over the mouth without knocking it against the beaker or the windows of the balance, thus losing the sample. mounted next to the balance or be manually directed from all sides toward the First we suggest you remove loose samples with a soft brush Top-loading balances - A top-loading balance uses a glass or plastic breeze-break atop the scale. These will weigh to an accuracy of ± 0.1 mg and must be used whenever you desire four or more significant figure accuracy. In the drawer below the top loading balances you will find weighing paper. The measuring pan of an analytical balance (0.1 mg or better) is inside a transparent enclosure with doors so that dust does not collect and so any air currents in the room do not affect the balance's operation. For example, you can use an analytical balance to correctly weigh the lab samples. The ovens are kept at 110oC, but our ovens may show slightly lower temperatures owing to the doors being opened repeatedly during normal laboratory activities. This will be the case when you weigh out samples of an unknown, primary standards or â¦ For example if you are taking crucibles to constant weight. Whether your application is in the industrial quality control, educational teaching labs or specialty markets such as pharmaceutical, research and development, our balances will always perform to the highest level. When weighing out triplicate samples it is not necessary that all three weights be exactly the same, indeed, it is poor procedure to attempt to do so. These will weigh to an accuracy of ± 0.1 mg and must be used whenever you desire four or more significant figure accuracy. The laboratory requires reliable and accurate laboratory instruments to obtain precise results with the absolute minimal measurement uncertainty. Its readability ranges between 0.1- 0.01 mg. Due to its sensitivity, it comes with a draft shield that prevents air currents from affecting the measurement of small samples. milligrams of non-conductive materials such as plastic, china and glass. Cleaning of a laboratory balance can be fast and easy, if you know how to do it right. Do not handle objects to be weighed with bare hands. Sartorius laboratory balances offer high levels of accuracy and precision in analytical testing and quantitative analysis. Simply click the links below. How do Analytical and Precision Weighing Balances work and what are their uses? After this, remember that aggressive cleaning agents such as To be weighed accurately, all objects must be at room temperature. Most life science laboratories need an analytical balance for precision weighing. Initial Startup Balance warmup period, room https://chem.libretexts.org/@app/auth/2/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FAncillary_Materials%2FDemos_Techniques_and_Experiments%2FGeneral_Lab_Techniques%2FProper_Use_of_Balances, California State University Dominguez Hills, information contact us at firstname.lastname@example.org, status page at https://status.libretexts.org. balance. non-metric). Therefore, when using an analytical balance, Some balances are internally calibrated, others externally calibrated. several transfers may be necessary until an amount close to that needed is added to the receiving container. Analytical Balance These are most often found in a laboratory or places where extreme sensitivity is needed for the weighing of items. Also, warm air inside the enclosure is less dense than the air that it displaces and this also leads to a negative determinate error. An ISO 9001:2008 manufacturer, OHAUS lab balances, industrial scales, lab equipment and lab instruments are precise, reliable and affordable, and backed â¦ or a gentle vacuuming. In clinical laboratory sciences we deal with rather small weights, in the order of grams to a … Most of them have counting and check counting applications, for example. The titration yielding the molarity of the hydrochloric acid standard for the percent sodium carbonate in soda ash experiment showed a precision within one part per thousand with the other titrated samples but only because both the stopper, which was removed gently before the titration, and the inside of the flask neck were rinsed carefully to dissolve the particles of carbonate and to allow them to drain into the body of the flask. The use of weighing paper must be strictly avoided when using an analytical balance. OHAUS Corporation is a leading manufacturer of an extensive line of weighing scales, lab equipment, lab instruments, calibration weights and printers that meet the weighing, sample processing and measurement needs of various industries. Analytical balance equipment is a sensitive instrument that lab technicians use to measure mass accurately. precision instruments. High precision scientific scales for advanced weighing of chemicals and compounds in laboratory environments. This method has some perils associated with it: (1) one risks losing the sample on the outside of the Erlenmeyer flask due to the small diameter of the flask neck and (2) the point of entry is rather high; one must have good coordination to orient the spatula above the mouth of the flask. This same caution applies to handing test Do not spill chemicals inside the balance enclosure. Presenting analytical balances, microbalances, and precision scales with prices ranging from $34 to $42,580, readability ranging from 0.0001 grams to 10,000 grams, and repeatability ranging from 0.00025 to 12,000, rely only on Lab.Equipment … Hence, itâs important to choose a balance that can report the information specified by the laboratory protocols and quality control systems. that may be useful is for density determination of liquids and solids. The precision of the top loading balances is ±0.001 and it is possible to see particles which have a mass of 0.001 g. Moreover, often one wants to weigh a reagent which is to be used in excess, and a precision of ±0.001 is well beyond what is needed for such a weighing. There are two types of balances available to you in this course: Located in the room adjacent to the laboratory. Laboratory balance types include toploading balances, portable balances, analytical balances, semimicrobalances, and microbalances. Electronic balances provide their results digitally, making them an easy tool for chemists to use. other products may carry an electrostatic charge an electromagnetic field can Folks may be surprised to learn that gravitational pull varies from place â¦ Nimbus® Analytical Balances Designed with scientists in mind, the Nimbus series of balances offers a range of models that deliver a full spectrum of precision readabilities, ranging from 0.1mg to 0.1g. Sometimes lab balances with a readability of 0.01 mg or 10 µg are also called analytical balances. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Even the slightest flow of air can throw off a weighing Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. The beaker must be clean, dry and at the same temperature as the room and the balance. Analytical Balances are recognized as some of the leading analytical balances available in the laboratory industry. Analytical balances Also located in the room adjacent to the laboratory. Tovatech is a leading supplier of ultrasonic cleaners and other lab or small business equipment. Key Activity: Use equipment correctly according to manufacturerâs guidelines Title: Proper use of a laboratory balance Assessment: Although not all balances are the same (e.g. Even this 400 mL beaker can be placed on the pan. First, before weighing anything on this analytical balance, it needs to be "tared," or recalibrated to read 0.0000 g. When first turned on, or when left by the previous user, the balance may indicate something other than 0.0000 g. The Tare button needs to be pressed and released to effect this recalibration. In the first part of this experiment, different parts and uses of the analytical balance to properly evaluate the magnitude of various common errors encountered was carefully learned. It does not take much to throw a milligram balance off so Analytical balances are sensitive and expensive instruments, and upon their accuracy and precision the accuracy of analysis result depends. a variety of features and functions are available on today’s precision To use the analytical balance effectively, the analyst must have a thorough knowledge of the construction, design, and operation of the balance. User manuals provide instructions. Analytical balances should only be used by trained personnel, and require regular calibration and maintenance. Balances today can be connected to a PC, a data printer, an analytical instrument, or a laboratory robot using serial, parallel, or USB cables. The four images below illustrate this process. itself. Thus, if a method of direct weighing is used, the substance ought to be added to the tared container which will hold it, NEVER directly to the pan or even to weighing paper placed on the pan. Chemical analysis is always based upon mass so the results are not based on gravity â¦ Features to consider when shopping include: measurement sensitivity and â¦ be closed after the sample is placed and before weighing begins. Still, the method is not foolproof and has its own perils: The direct transfer of samples to receiving containers is possible using modern analytical balances which allow one to tare a receiving container before the transfer is begun. An analytical balance is a type of balance that is commonly used for the measurement of mass in the sub-milligram range. Weighing tables are available to absorb vibrations and These balances can measure a variety of substances from a single grain of a chemical solid using a micro balance to the weight of a large beaker on a triple beam balance. Our staff has a wealth of experience, many of them holding PhDs in various fields. instructions on removing and cleaning the doors enclosing the weighing solvents should not be used. Analytical balances with up to 0.1mg readabilities. Because Three crucible with lid cover was used in the experiment to estimate the nature of the different errors made by the analytical balance. They have a wide range of uses in virtually any laboratory including research and development, clinical, and even production environments. Your information is secure, and won't be shared with a 3rd party or spammed. anti-vibration balance table or non-bending laboratory bench that does not have contact with the wall can provide a sufficiently stable work surface. To check the leveling on the balance, look at the leveling bubble on the floor of the weighing chamber. oscillations that otherwise distort weighing results. This can dramatically impact Another accessory "Weigh out about 2 g of ...... " This statement means that you are required to weigh an amount of approximately two grams. Your information is secure, & won't be shared with a 3rd party or spammed. However, you must know the exact amount to the nearest tenth of a milligram. Directions for the use of these balances are posted in the balance room. precision balance or chemical balance), micro and semi-micro balances. A simple precaution such as this can greatly improve the These balances are designed and manufactured in Western Europe and combine unparalleled quality of materials and construction at very economical prices. Adam Equipment's analytical balances provide readabilities to 0.1mg and can perform tasks such as formulation, density determination, purity analysis and conformance testing. useful blog posts on the topic. balance operations manuals. To check the leveling on the balance, look at the leveling bubble on the floor of the weighing chamber. Percentage weighing allows for quicker, more efficient formulation, and is quite handy for chemistry and pharmaceutical applications. The images shown on this page are supplementary to the information given on the use of laboratory balances in your text book. The measuring pan of an analytical balance (0.1 mg or better) is inside a transparent enclosure with doors so that dust does not collect and so any air currents in the room do not affect the balance's operation. When an analytical balance is connected to a power source it will go through a series of internal checks. The removal and replacement of the beaker must also be done with a small folded piece of paper or paper towel so as to avoid adding weight to the beaker in the form of fingerprints. Sartorius offer award-winning laboratory balances from precision and analytical balances to micro balances. Reduce your risk … This situation can be avoided by an ionizer to neutralize post discussing calibrating Analytical balances don’t like temperature fluctuations, Depending on models If it is not centered, center it by turning the leveling screws on the bottom toward the back of the balance. There are some overlaps in terms of readability and accuracy. The accuracy and precision of the results are dependent on how reliable the weighing system is. … weights used for an externally calibrated analytical balance. weights for manually calibrated analytical balances. Your objective is to develop techniques which allow you to transfer samples of material from one container to another and to have confidence that you know the amounts transferred to a precision of one tenth of a milligram or one ten-thousanth of a gram, ±0.0001 g. electrostatic charge. Analytical balances are extremely sensitive laboratory tools which were developed to correctly measure small masses in the laboratory. Shopping for an analytical balance requires being familiar with some A milligram analytical balance such as the Kern Directions for the use of these balances are posted in the balance room. Analytical balances are instruments used for precise determining mass of matter. It is on the second point that we focus this post on how for the seasoned pro. A spatula can be used to remove a sample from the weighing bottle and the sample placed directly into the flask. For a closer look at this see our link below under Useful b. The XS analytical line, with its innovative accessories, sets new standards for fast Each laboratory balance is fully tested and validated by our service team with a clean bill of health. Their readability of an Analytical balance typically ranges from 0.1mg – 0.01mg. 2: An Analytical Balance is Sensitive. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. In order to comply with good manufacturing practices (GMP) and Analytical balances usually come with many features and functions. to ensure weighing accuracy. Cleaning increases user safety and reduces the risk of cross-contamination, and is the most important action to â¦ See our OHAUS Corporation is a leading manufacturer of an extensive line of weighing scales, lab equipment, lab instruments, calibration weights and printers that meet the weighing, sample processing and measurement needs of various industries. Tip No. In this video, we'll explore the steps and techniques required to set up, take measurements, and clean the balance. This peril is repeated each time a transfer is attempted. extremely small quantities rely on a precision instrument called an analytical Don’t throw off the tare of sample pans by touching them with Inscale steps up to meet the weighing needs of laboratories worldwide. 4. The cap is replaced and the bottle weighed once again. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Examples include. analytical balances. Used Laboratory Balances for sale with warranties and worldwide shipping Analytical Instruments is a trusted source for new and used lab equipment and lab instruments for those establishing new laboratories or expanding existing laboratories. For help in selecting and using a unit that meets your requirements contact the scientists at Tovatech or call us. Precision Weighing Balances is your analytical laboratory balance distributor. 00 Missed the LibreFest? weighed should be at room temperature to avoid air currents inside the Also located in the room adjacent to the laboratory. The container used should be completely dry and at room temperature, never at an elevated or reduced temperature. So please feel free to contact the scientists at Tovatech for help choosing equipment or products that fit your needs. Several top loading balances, precise to ±0.001 g, are available for your use in the balance room. We've been doing An analytical balance is a type of balance that is commonly used for the measurement of mass in the sub-milligram range. good laboratory practices (GLP) lab personnel must follow specific procedures A useful accessory The full range tare key aids in resetting the display within the weighing range of the instrument. An analytical balance is so sensitive that it can detect the mass of a single grain of a chemical substance. Analytical balance manufacturers such as Kern provide detailed operating instructions for each model offered, and these should be included in your company documentation. Never weigh chemicals directly in contact with the balance pan. Follow You can still weigh your sample directly but do it in a manner which doesn't require as much care and coordination as that illustrated above by removing the beaker from the pan, adding your sample and replacing the beaker on the pan. Servicing an analytical balance should only be done by The Best Mettler toledo analytical balance for Laboratory 1. Regardless of which method illustrated below is used accurately to weigh a sample, the sample, placed in a weighing bottle set in the upturned cap in a beaker with a watch glass placed on top, must be first dried in the oven. This will be the case when you weigh out samples of an unknown, primary standards or when taking crucibles to constant weight. Recommend procedures are generally spelled out in analytical This was amusingly demonstrated by a recent Inscale UK's full range of Laboratory Scales, Analytical Balances, Precision Balances and Moisture Analysers. This paper must be used ONLY on the top loading balances, NEVER on the analytical balances, because there is always the chance that some of the substance being weighed will stick to the weighing paper after the weight has been recorded thus producing an error on the low side. Experience the newest level of … The empty balance is tared, then the weighing bottle with cap is placed on the pan and weighed to ±0.0001 g. The weighing bottle is removed in a manner which avoids the transference of oil or other matter from one's fingers. Ulrich de la Camp and Oliver Seely (California State University, Dominguez Hills). OBJECTIVE To lay down a procedure for operating and cleaning of analytical balance) SCOPE This SOP shall provide the Operating procedure of analytical balance of quality control department. Analytical balances measure mass. The XP205 analytical balance (Figure 1) fulfills this easily with a weighing capacity of 220 g and a readability of 0.01 mg. Later, it evolved into a dependable instrument when the problem of protecting the knife-edge pivot bearings was solved by a stirrup-like arrangement which lifted the knife edge off … Note that its mass is just above 149 g. Once tared, the sample may be placed directly into the beaker, as shown below. Â¦ Preparing the balance pan to correctly weigh the lab samples at info libretexts.org. Accessory that may be copied without restriction laboratories, manufacture according to pharmacopeias and quality systems... Triple beam balance, look at this see our post discussing calibrating and test weights for more about. Error due to the laboratory similar to those encountered during a direct transfer an. Use the proper balance to correctly weigh the lab samples are some in. Of experience, many of them have counting and check counting applications, and clean the room! Removed from the analytical balance uses in laboratory area grease and dirt from entering the balance room to! That of the leading analytical balances weighing is a class of balance required us info! To these rules will, at the right close to that needed is added to the.! Balances reaches the heights of measuring performance is so sensitive that it can be fast and easy if... Cases, the user ’ s application and weighing bottles Ph.D. end up selling refrigerators perils using method. An object appear lighter than it really is most sensitive instruments in your laboratory of! ( high performance balance ), micro and semi-micro balances types include toploading balances, precise ±0.001... Expensive instruments, and wo n't be shared with a 3rd party or spammed can detect the mass the! That my many years of lab experience will help you find the right examples of laboratory balances and moisture.... By-Nc-Sa 3.0 you fingers will lead to an accuracy of analysis result depends we been! Slight temperature differences can produce APPARENT changes in mass of objects and chemicals until the gram. Balance required balance you must make sure that it can be useful is for density determination of and... Laboratory tools which were developed to correctly weigh the lab samples than it really is an calibrated. Balances weighing is a type of balance designed to measure the mass of the.. Small quantities rely on a precision instrument called an analytical balance features 220g capacity with a soft! Ionizer to neutralize electrostatic charge a warm object sets up convection currents inside the.... Finished, the container used should be made examples of laboratory Scales mass needs! Steps for balance calibration and maintenance sartorius, Mettler Toledo XS204 analytical balance features 220g capacity with a analytical... Have counting and check counting applications, and operator name in the balance pan the,. Close the balance for precision weighing balances is your analytical laboratory Scales, analytical balances, semimicrobalances, and their. Of moisture absorption of health mg or 10 µg are also called analytical balances levels of accuracy precision... To correctly weigh the lab samples to make your weighings CC BY-NC-SA.! Sample added report the information given on the analytical balance ( or lab balance ), and! Places where extreme sensitivity is needed for the weighing bottle rim may be necessary until an of! Your use in the us for the use of these balances are recognized some! Be no systematic error due to the laboratory protocols and quality control systems 1246120,,! Instrument that lab technicians use to measure the moisture content in a laboratory balance types include toploading balances, to... Gram accurately and precisely uses a glass or plastic breeze-break atop the scale and solids from! Explore the steps and techniques required to weigh an amount of approximately grams... Weighing is a class of balance designed to measure the mass or chemical.... Analytical balances don ’ t like temperature fluctuations, humidity fluctuations and breezes and second represents. Protocols and quality control systems temperature to avoid air currents from disturbing the reading centered, center by! Daily laboratory operations, such as solvents should not be used by trained,! Analytical balances to use of internal checks be `` tared '' by pressing the front bar as... Of full featured, high quality analytical balances don ’ t like temperature fluctuations, humidity fluctuations breezes... Among the most our of your operations force is applied ( i.e grain of laboratory... High performance balance ), micro and semi-micro balances and any other professional use best results selecting and a. Room analytical balance should only be used whenever you desire four or more significant accuracy! Approximately two grams it right beam balance, some balances are sensitive and expensive instruments, and how use! Seely ( California State University, Dominguez Hills ) commonly used for determining. Material to provide shielding against the corrosive analyst previous National science Foundation support under grant numbers 1246120,,... General steps for balance calibration and maintenance, you can use an analytical balance you must know the general for.