Rounding in K problems

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claudia_1h
Posts: 111
Joined: Fri Aug 09, 2019 12:16 am

Rounding in K problems

Postby claudia_1h » Sun Jan 12, 2020 3:32 pm

In the solution for problem 5I.23, I noticed that the values for the equilibrium concentrations of the reaction were rounded according to sig figs before they were plugged into the equation to find Kc. Is this a universal rule for rounding? If not, how do we know when to apply sig figs?

Timmy Nguyen Dis 1I
Posts: 107
Joined: Sat Aug 17, 2019 12:17 am

Re: Rounding in K problems

Postby Timmy Nguyen Dis 1I » Sun Jan 12, 2020 3:40 pm

I think only the final answer is rounded.

Jasmine 2C
Posts: 184
Joined: Wed Sep 18, 2019 12:18 am

Re: Rounding in K problems

Postby Jasmine 2C » Sun Jan 12, 2020 3:47 pm

I don't know why they were rounded before plugging in. But the general rule for tests, midterm, and final is to keep as many digits as possible (in multi-step problems) for each calculation and at the end when you have a final answer, go according to the least number of sig figs in the problem.

Aiden Metzner 2C
Posts: 104
Joined: Wed Sep 18, 2019 12:21 am

Re: Rounding in K problems

Postby Aiden Metzner 2C » Sun Jan 12, 2020 3:51 pm

You aren't supposed to round until the end, the answer will be the most accurate if the exact numbers are used until the final answer.

JohnWalkiewicz2J
Posts: 103
Joined: Thu Jul 11, 2019 12:17 am
Been upvoted: 1 time

Re: Rounding in K problems

Postby JohnWalkiewicz2J » Sun Jan 12, 2020 3:51 pm

Yeah id say just use the exact values the problem give you when calculating Kc and then apply sig figs to your final answer.


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