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flyingsliverfin
September 3rd, 2011, 06:18 AM
HI! I'm currently taking AP chemistry and we just wizzed past significant figures. The teacher just told us "all the zeroes on the left are not significant" without a reason. Would someone mind providing? :)

Thanks

agillator
September 3rd, 2011, 07:05 AM
en.wikipedia.org/wiki/Significant_figures gives a good explanation.

Legendary_Bibo
September 3rd, 2011, 07:31 AM
Every Physics professor I've had told me that for significant figures we should put how much we think we should put.

September 3rd, 2011, 07:10 PM
HI! I'm currently taking AP chemistry and we just wizzed past significant figures. The teacher just told us "all the zeroes on the left are not significant" without a reason. Would someone mind providing? :)

Thanks

leading zeros are just a matter of scale and can be removed by rescaling.
1g has one significant figure.
0.001kg has still one significant figure and means the same just rescaled to kilogram.

keithpeter
September 3rd, 2011, 08:52 PM
leading zeros are just a matter of scale and can be removed by rescaling.
1g has one significant figure.
0.001kg has still one significant figure and means the same just rescaled to kilogram.

+1 for this idea

Try writing all your numbers in Standard Form (aka Scientific Notation) for a few calculations...

0.00003 becomes 3.0 x 10^-5 and 12 500 000 becomes 1.25 x 10^+7

You get to separate the significant figures from the power of 10 that defines the scale.

cheers

BeRoot ReBoot
September 4th, 2011, 01:21 AM
+1 for this idea

Try writing all your numbers in Standard Form (aka Scientific Notation) for a few calculations...

0.00003 becomes 3.0 x 10^-5 and 12 500 000 becomes 1.25 x 10^+7

You get to separate the significant figures from the power of 10 that defines the scale.

cheers

This. "Significant figures" are just a way to introduce scientific notation into numbers described in another method. Just always use scientific notation and there can be no doubt about how many "significant figures" there are.

flyingsliverfin
September 4th, 2011, 01:42 AM
that makes more sense.
Thanks!

T2manner
September 4th, 2011, 03:14 AM
Usually when you're doing open response questions, you use as many significant figures as the given information has.
So if you're given 15.5 g of oxygen, and you need to find moles, and your answer is .9087592742 mols, then you'd make it .909 .

Besides scientific notation, it's used for knowing what decimal to round to.

devondashla
September 4th, 2011, 03:17 AM
EDIT: Go here to see my original post properly.

http://pastebin.com/0W5TyEV1

flyingsliverfin
September 5th, 2011, 07:06 PM
haha thanks for writing it all out devondashla :)