Question

Help me with Significant figures?

Answer 1

i have attach a data table from a lab calculations

Answer 2

Joseph Stalin
Napolean
Jesus
All very signifigant

Answer 3

hahaha you forgot michael jackson

Answer 4

Very true, very true.

Answer 5

Are you multiplying or adding with your numbers?

Answer 6

well the burete readings are manually done from reading the burrete

Answer 7

mmk. But when you do some math, will you be doing multiplication? I haven't done chem in a while, so I just want to confirm my theory that you're doing multiplication.

Answer 8

the concentration are calculated with

0.00811L x 0.0200MnO4/1L x 5mol H2O2/2mol MNO4 x 1molH2O2/5mL = 0.0811MH2O2

Answer 9

hope you understand that

Answer 10

Ah ok. It's just multiplication and division, then. Awesome.

Answer 11

And strangely enough, I do understand that stuff. Good ole stoichiometry/dimensional analysis. :D

Answer 12

You've done it correctly. Your final answer should be equal to the number with the fewest sig figs, which I saw as all being 3. So, .0811 is correct.

Answer 13

funny i dont seem to be able to do any of these when it comes to
test. =)

Answer 14

what if i convert 5mL to L 0.005 will it affect it?

Answer 15

nope! When it comes to conversion, they have 'infinite' sig figs. At least for certain stuff. Like... 1 liter is "exactly' 1000 milliliters. Or... 1000.00000000000000000000... milliliters.

Answer 16

Likewise with feet to inches. 1 foot is 'exactly' 12 inches, so you won't hurt your sigfigs with it.

Answer 17

However, a kilometer is 'about' 3280 feet, so at this point, it'll affect your sigfigs. Basically, if you are converting from one system to another, you're going to hurt your sig figs. Otherwise if you're just switching between related units, you're ok. So meters to centimeters won't hurt. But... gallons to liters... that will be a problem.

Answer 18

hmm the 9.21 and 17.03 on my readings doesnt have to be the same sig fig?

Answer 19

That part is a problem (I didn't take a close look at your readings). In this instance, your final answer will have to have 3 sig figs.

Answer 20

But it is ok if you keep the 17.03 while you work with the calculations. I mean... the teacher might be like "what? Why did you suddenly go to .xxx from .xx?" but other than that, it shouldn't be a big issue. A hint, though: You should never guess more than 1 unit above the lines on a buret.

Answer 21

For example, if the buret goes straight from 1 to 2 millimeters without lines in between, you can guess something like 1.5. But do not guess 1.53, as you have no justification for going beyond the 1.x

Or if the buret has lines for 1.1, 1.2, 1.3... you CAN guess that it's at 1.13, but do NOT guess something like 1.135

Answer 22

Make sense?

Answer 23

yup! thanks friend

Answer 24

chemistry have been really hard for me

Answer 25

=) i cant seem to remember how to do calculations

Answer 26

No problem. I actually quit my major (pharmacy) because Chemistry 2 killed me. :(

Answer 27

Erm.... not advocating you do the same. I just didn't try as hard back then. I'm going to go back to pharmacy once I finish my (easier) computer engineering degree.

Answer 28

aww sorry about computer engineering is easier?? LOL