When testing materials, the error in the amount of sample taken is to be controlled within ±0.0002g. How can this be achieved?
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When testing solid powder materials, the error in the amount of sample taken is to be controlled within ±0.0002 g. How can this be achieved? We use spoons to scoop it by hand, and it’s difficult to control – either too much or too little is scooped
There are no shortcuts for this. It’s just practice. Just practice more* and it will be fine
This post was last edited by qugd on 2018-10-8 at 14:13. That metric refers to the precision achieved when using a balance in analytical testing; an accuracy of 0.0002 grams is required, and analytical balances are capable of achieving such precision. For example, if you need to weigh a sample with a weight between 0.25 and 0.26 grams, you can accurately measure any of the following representative weights: 0.2516 grams, 0.2583 grams, or 0.2592 grams; it’s not necessary to measure exactly 0.2500 ± 0.0002 grams. You should take a close look at books on the basic knowledge of analytical chemistry.
During testing, the weighing error doesn’t need to be too large; just record the accurate values and use them in the calculations to obtain the result. It’s not necessary to weigh things with precision equal to that of the scale.