Chemistry: Significant Figures and Addition

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Discussion Overview

The discussion revolves around the application of significant figures in the context of addition in chemistry, specifically focusing on how to express the final answer correctly based on the significant figures of the initial values provided.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions whether the answer to the addition problem should be expressed as 0.00030 M, considering the significant figures of the original numbers.
  • Another participant agrees that the answer should maintain five decimal places, supporting the initial participant's claim.
  • A different viewpoint suggests that the answer should be 0.0003, arguing that expressing it to five places results in 0.00029..., which has two significant figures, while 0.00030 has two significant figures and is not appropriate for the context.
  • There are multiple instances of participants humorously reflecting on their own calculations and the correctness of their math skills.

Areas of Agreement / Disagreement

Participants express differing opinions on how to correctly represent the final answer in terms of significant figures, indicating that multiple competing views remain on this topic.

Contextual Notes

There is a lack of consensus on the correct application of significant figures in the addition problem, particularly regarding the interpretation of the final answer's significant figures.

Soaring Crane
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Homework Statement



I just wanted to know if I wrote the answer with the correct number of significant figures for this addition problem.

0.00015 M + 0.00004 M + 0.00011 M = 0.00030 M (Correct?)


Homework Equations



See above.

0.00015 M + 0.00004 M + 0.00011 M = ?

The Attempt at a Solution



See Part 1.

All of the original numbers have 5 decimals places, but only the first and third values have 2 significant figures. (The second has 1 significant figure.) Therefore, the final answer must be expressed with 5 decimal places, and will have 2 significant figures (0.00030 M)?

Thank you.
 
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You have all the place values known to the fifth decimal place, so yes, take to the fifth decimal place.
 
I would say that the answer was 0.0003. If you were to express the answer to 5 places you would get 0.00029... that is two sig figures and you are allowed one. 0.00030 has two sig figures and you are allowed one.
 
0.111+0.222+0.0001=0.3 then?
 
Borek said:
0.111+0.222+0.0001=0.3 then?

Yikes! Of course you are correct, Borek. Good catch. You will also note that I cannot even be trusted to correctly add three numbers together as well...
 
We each did some rethinking and are a bit better for doing so.
 
haha should you really be helping people with that kind of math? XD just kidding :P
 
Sometimes I amaze myself.
 
chemisttree said:
Sometimes I amaze myself.

Don't feel alienated :smile:
 

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