Calculations With Significant Figures

Moderators: Chem_Mod, Chem_Admin

William Chan 1D
Posts: 102
Joined: Sat Sep 14, 2019 12:15 am

Calculations With Significant Figures

Postby William Chan 1D » Sun Sep 29, 2019 6:27 pm

When I do multiple calculations in my calculator, should I round every answer before I carry onto then next step using the appropriate number of sig figs, or should I just use the exact numbers the calculator gives me and at the end round using sig figs?

Trinity Vu 1D
Posts: 53
Joined: Fri Aug 30, 2019 12:15 am

Re: Calculations With Significant Figures

Postby Trinity Vu 1D » Sun Sep 29, 2019 6:32 pm

You should always save using sig figs for when you get your final answer instead of during calculations. For example, if you had to convert 5.63 g O2 to moles and then to atoms, you would put the answer in 3 sig figs but you wouldn't put the mid-calculation, the moles, in sig figs (just use the exact number you get on your calculator) because this would end up throwing off the final answer and in certain cases would produce the wrong final answer and then you would only get partial credit for the problem.

Robert Tran 1B
Posts: 118
Joined: Thu Jul 11, 2019 12:15 am

Re: Calculations With Significant Figures

Postby Robert Tran 1B » Sun Sep 29, 2019 9:48 pm

You should always store exact values in intermediate calculations, or else there will oftentimes be significant error in the final resulting calculation. The amount of error increases for every calculation if the values are rounded. Because of this, you should only apply significant figures once all the calculations have been finished.

Posts: 51
Joined: Sat Aug 24, 2019 12:16 am

Re: Calculations With Significant Figures

Postby RoshniVarmaDis1K » Mon Sep 30, 2019 8:46 pm

When doing these problems it is best not to round after each step. Instead, just input the answer given on your calculator into the next line and go from there.

At the end of the problem, apply the sig fig rules to the final answer. Make sure to keep track of the proper number of sig figs at every step, and keep in mind the different rules for multiplication/division vs. addition/subtraction.

Return to “Significant Figures”

Who is online

Users browsing this forum: No registered users and 2 guests