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When it comes to finding the mass percent composition of a substance how many sig figs should we round to? Or is there a certain amount of decimal places we need to round to? Or does it not make a difference? I've noticed that in the textbook solution they'll usually do up to two decimal places, but I've also seen them do up to four.
Should use significant figures instead of decimal places because finding the mass percent composition uses division. The number of significant figures in your answer should be the same as that of the value with the least significant figures that you use in the calculation.
In this calculation you are typically multiplying or dividing, and the rule when it comes to significant figures in multiplication or division the rule is that your answer should have the same number of significant figures as the factor with the least number of significant figures. And also make sure you are rounding up or down as needed. For example, if you are multiplying 2.05 (a number with 3 significant figures) and 3.7 (a number with 2 significant figures), you would have to write your answer with 2 significant figures. Your answer would be 7.6.
Hi yeah you just have to use the least amount of sig figs and I usually wait till the end to do so just because it’s less of a hassle doing it in between problems. However there are different rules between multiplying numbers and finding dog figs than if you were adding numbers which I would just review looking at a khan academy video.
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