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Mass % comp accuracy F5

Posted: Thu Oct 03, 2019 7:12 pm
by Lara Kristine Bacasen 1L
Alright so I was doing F5 and when I did the percentages I got values different from the solutions manual but they still result to 100% when added together. I know how to do it but I think there is a difference because of the masses I'm using for the individual atoms and molar mass. Do you think it is okay to leave my answer even though it is different from the solutions?

Re: Mass % comp accuracy F5

Posted: Thu Oct 03, 2019 8:17 pm
by Sarah Blake-2I
Yeah I think it is fine if you get slightly different answers than the solutions manual. I know this happened to me a few times already, but my answers were pretty close to the solution manual, so as long as they are very close, I think it is fine. Also, Dr. Lavelle has a link on his website with mistakes in the solutions manual, so maybe check that as well. :)

Re: Mass % comp accuracy F5

Posted: Thu Oct 03, 2019 10:37 pm
by Charisse Vu 1H
Yes, I believe it's totally fine! It depends on the periodic table you are using too. Some periodic tables round off at different sig figs so you should be fine.

Re: Mass % comp accuracy F5

Posted: Fri Oct 04, 2019 1:19 am
by Ashley R 1A
It should be fine :) The purpose of sig figs is to account for inaccuracies like that anyways, so as long as you show your work we won't get docked points !

Re: Mass % comp accuracy F5

Posted: Fri Oct 04, 2019 1:32 am
by Osvaldo SanchezF -1H
So it is best to hold off in rounding till the end because you may encounter inaccuracies. My TA also told me that when you find the molar mass of a compound or element, you should be very accurate going to the last decimal, at least at the start. However, as long as the values are very close to each other then it should be fine but make sure it is not too inaccurate such as it being 700g but you get like 670g. Although it does seem very close, it is quite a difference, and in fact, could have occurred through a computational mistake and not sig fig one.

Re: Mass % comp accuracy F5

Posted: Fri Oct 04, 2019 7:33 pm
by Mellanie Gamero 4D
I think a slight difference in the solution you get versus the solution that is given shouldn't be too much of a problem. As long as they both roughly round up to about the same answer it should be fine(that is if the solution is within decimal form).