Chemistry: Significant Figures and Addition

[Soaring Crane]

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.

 

[symbolipoint]

You have all the place values known to the fifth decimal place, so yes, take to the fifth decimal place.

 

[chemisttree]

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.

 

[Borek]

0.111+0.222+0.0001=0.3 then?

 

[chemisttree]

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...

 

[symbolipoint]

We each did some rethinking and are a bit better for doing so.

 

[link2110]

haha should you really be helping people with that kind of math? XD just kidding :P

 

[chemisttree]

Sometimes I amaze myself.

 

[Borek]

Sometimes I amaze myself.

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