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Module: Molarity #15

Posted: Wed Oct 10, 2018 11:16 pm
by Mariam Baghdasaryan 4F
15. Calculate the concentration (molarity) of a glucose solution containing 0.1 moles of glucose in 0.4 liters of water.
A. 0.25 mol.L-1
B. 4.0 mol.L-1
C. 2.5 mol.L-1
D. 2 mol.L-1

.1mol/.4L=.25 mol. L-1. So I got this for the answer but I was confused why the answer is exact and not 1 sig fig (.2)

Re: Module: Molarity #15

Posted: Wed Oct 10, 2018 11:50 pm
by jonathanjchang2E
I don't think multiple choice questions are as stringent on significant figures.

Re: Module: Molarity #15

Posted: Thu Oct 11, 2018 1:07 am
by Tony Ong 3K
That is strange! I would say to always keep the habit of putting the correct sig figs regardless because it's 1 point off per question on the midterms and finals!

Re: Module: Molarity #15

Posted: Thu Oct 11, 2018 9:55 am
by Courtney Quan 1C
I'm not sure either, but I refer back to the given information of the problem when determining the number of significant figures in my answer. You shouldn't have more significant figures in your answer than was present in the information with the least number of significant figures in the question. At least you got the answer right!

Re: Module: Molarity #15

Posted: Fri Oct 12, 2018 12:12 am
by Rachana Jayaraman 1H
On the actual test you would round 0.25 to 0.2 because of sig figs, but I think that the answer is 0.25 on this question is to prevent confusion since people may not be considering sig figs while taking the assessment.

Re: Module: Molarity #15

Posted: Sun Oct 14, 2018 10:20 pm
by Joussie Camacho 4I
You wouldn't round up to 0.3?

Re: Module: Molarity #15

Posted: Mon Oct 15, 2018 4:26 pm
by Courtney McHargue 1I
Since 0.25 isn't followed by any other decimal values after the 5, normally this answer would and should be rounded to 0.2 since both of the values getting you to this answer had only one significant figure.