Science questions not covered in Chem 14A and 14B. Try to limit questions to chemistry (inorganic chemistry, physical chemistry, organic chemistry, biophysical chemistry, biochemistry, materials science, environmental chemistry).
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Typically, it is best not to round the atomic weights of the elements before using it for calculations because your final answer would not be as accurate as it could be. Usually, you would round at the end of your calculation depending on the amount of significant figures there are. You determine the amount of significant figures through the given/ starting amounts within the problem. Keep in mind, this also depends on the type of problem and how accurate you want your answer to be!
I tend to use the entirety of the atomic weight listed for that element on the periodic table. I only round at the very end for the final answer and that depends on how many significant figures are used in the given values that is stated at the very beginning from the question.
It is best to not round the atomic weight in order to produce a more accurate result, especially when having to conform to the appropriate number of significant figures. However, if the number is very long, I usually round to the nearest thousands place.
Usually, the question or the previous questions should give you an idea of how much you should round. When I round, I look at the previous questions and if they rounded to the nearest hundredth than I round to the nearest hundredth. If they do it to the thousandth than I do it to the thousandth, and so on. Hope this helps :)
Gillian Ward 4H wrote:How should you round the atomic weights of the elements on the periodic table when using it for calculations and how many decimal places should you go out to?
I usually use the entire atomic weight given so that my final answer is more accurate than if I were to round from the start.
rounding atomic weight/mass can lead to small discrepancies so it's best not to do so until you've reached your answer. Usually I try to include at least three numbers after the decimal for accuracy when rounding to find the number of moles.
The safest way to prevent incorrect rounding early on is to use the entirety of the number given on the periodic table. With other pieces of data, rounding is more difficult to fully avoid, but avoiding rounding with Periodic elements will produce the most accurate answer possible, and then it can be rounded to the lowest amount of significant figures given in the question.
Katie Sy 1J wrote:I tend to just use the whole number listed on the periodic table to make sure my answers are exact as possible, but if it's a super long number, I usually stop after 3 decimal places
That's helpful to know thank you
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