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sig. figures & decimal places in data and uncertainties


beatriz

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Hey there! :)  so there are maany 'theories' about the number of significant figures and/or decimal places that all the data needs to have. Some say that all the values have to have the same sig. fig. Some say that all the values need to have the same decimal places. Some say that the experimental data should have the same sig fig between them, but not compared to uncertainties. Other say that the uncertainties should have the same amount of decimal places, but not when comparing it to experimental data. Whaat??

 

So I attach one of the tables (in form of plain text) - it is a minor one, to show what I've done with the values (rounding them up) - I am totally unsure if this is right. (It doesn't show proper calculations or anything - & I'm sure I messed it up with the concentration, it is only to show my understanding of sig. figs). Thanks a lot.

IMSOSCREWED :(

 

so it is like parameter. unit. error. value.

 mass of ascorbic acid (solute). g. ±0.001. 0.250

volume of water (solution). ml Â±0.100. 250

volume of solution used in titration. ml±0.100.  25.0 

moles of ascorbic acid. mol  Â±0.001.  1.44

concentration of ascorbic. mass/volume percent (%). ±0.200. 0.100

 

agh it's hard to understand without table

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Hey there! :)  so there are maany 'theories' about the number of significant figures and/or decimal places that all the data needs to have. Some say that all the values have to have the same sig. fig. Some say that all the values need to have the same decimal places. Some say that the experimental data should have the same sig fig between them, but not compared to uncertainties. Other say that the uncertainties should have the same amount of decimal places, but not when comparing it to experimental data. Whaat??

 

So I attach one of the tables (in form of plain text) - it is a minor one, to show what I've done with the values (rounding them up) - I am totally unsure if this is right. (It doesn't show proper calculations or anything - & I'm sure I messed it up with the concentration, it is only to show my understanding of sig. figs). Thanks a lot.

IMSOSCREWED :(

 

so it is like parameter. unit. error. value.

 mass of ascorbic acid (solute). g. ±0.001. 0.250

volume of water (solution). ml Â±0.100. 250

volume of solution used in titration. ml±0.100.  25.0 

moles of ascorbic acid. mol  Â±0.001.  1.44

concentration of ascorbic. mass/volume percent (%). ±0.200. 0.100

 

agh it's hard to understand without table

The number of decimals in the uncertainty and the values have to be the same. 

For the moles of ascorbic acid. mol  Â±0.001.  1.44 , you need to have three decimal number in the value, therefore it should be 1.440. 

You do not need to write 0.100, (0.1) will be fine. 

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The majority of your decimal places look good. The only one that stuck out to me was commented on the above reply. Additionally, you added two extra decimal points than necessary in regards to your concentration. Other than that you're fine, so don't stress out about it. :) 

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