Relationship between density and molarity

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Ashley Zhu 1A
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am

Relationship between density and molarity

Postby Ashley Zhu 1A » Wed Oct 03, 2018 2:42 pm

Today in discussion we learned that density was related to molarity as they had similar equations (D = m/V and C = n/V) and were given the example:

6.54g (1cm^3/0.7857) = 8.32 cm^3 = 8.32 mL

While I understand the calculations and the relationship between cm^3 and mL, I'm not sure where the 6.54 or 0.7857 comes from since there was no other context provided, as far as I could tell. Would someone be able to explain this and perhaps give a practical application of this theory in a practice problem?

Thank you!

Amy Dinh 1A
Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

Re: Relationship between density and molarity

Postby Amy Dinh 1A » Wed Oct 03, 2018 2:56 pm

I'm assuming that you were given the mass of a substance (6.54 grams) and the density of the substance (0.7857 g/cm^3). Since the equation was D= m/V he substituted in D and m to find volume. I think he was trying to say like the C =n/V problems, you can find any variable of the D = m/V equation as long as you have two given variables.

To elaborate on the cm^3 to mL, 1 cm^3 is equal to 1 mL.

Hope this helps.

Nicolle Fernandez 1E
Posts: 56
Joined: Fri Sep 28, 2018 12:25 am
Been upvoted: 1 time

Re: Relationship between density and molarity

Postby Nicolle Fernandez 1E » Wed Oct 03, 2018 3:16 pm

I believe the 6.54g is the mass of the substance, then you divide it by (0.7857/1cm^3) because that is equal to 0.7857/1mL which is the density which is mass/volume.


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