Density of Water

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minendo

minendo

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Aug 31, 2001
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Anyone happen to know the density of water at 19C? I'm trying to write up this lab report, but in order to do the calculations I need the density of water at 19C. Our professor expected the room to be warmer than 19C so the only values we have for water density are at 20C and above.
 
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SoylentGreen

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Oct 17, 2002
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Water was used as the basis for establishing the metric unit of mass, however, so it is easier to remember that a cubic centimeter of it has a mass of 1 gm. Knowing that there are 1000 cubic centi- meters in a liter, you can also use 1 kilogram (1000 grams) per liter for water's mass density.
 
guyver01

guyver01

Lifer
Sep 25, 2000
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20 degrees C = 0.99823 g/mL

15 degrees C = 0.99913


The density of water depends on its temperature. Water?s maximum density of 1.0000 g/cm3 is at 3.98° C. The density falls as it approaches freezing.
Water?s density will start to fall at temperatures higher than 3.98° C, at 50° C, the density has fallen to 0.9880 g/cm3.

At 0° C, liquid water has a density of 0.9998 g/cm3.

 
minendo

minendo

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Aug 31, 2001
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Originally posted by: Kiyup
Water was used as the basis for establishing the metric unit of mass, however, so it is easier to remember that a cubic centimeter of it has a mass of 1 gm. Knowing that there are 1000 cubic centi- meters in a liter, you can also use 1 kilogram (1000 grams) per liter for water's mass density.
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The density of water changes as temperature changes thus causing water to have a different mass. At 4C it is known that 1g water = 1mL water, but for this experiment we used 19C water.

 
Evadman

Evadman

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Feb 18, 2001
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Originally posted by: Kiyup
Water was used as the basis for establishing the metric unit of mass, however, so it is easier to remember that a cubic centimeter of it has a mass of 1 gm. Knowing that there are 1000 cubic centi- meters in a liter, you can also use 1 kilogram (1000 grams) per liter for water's mass density.
Click to expand...

But the density of water changes baised on tempeature. IIRC it is densist at 4c. Unfortunately, I do not have my phisics book where I can get at it :(
 
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Moonbeam

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Nov 24, 1999
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I hope you realize that if water didn't expand at 4 degrees in either direction temperature wise, there would be no life on earth. WTF indeed. Good grief.
 
Evadman

Evadman

Administrator Emeritus<br>Elite Member
Feb 18, 2001
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Originally posted by: bGIveNs33
Originally posted by: minendo
Originally posted by: guyver01
20 degrees C = 0.99823

15 degrees C = 0.99913
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Thank you. I can extrapolate from there.
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Wouldn't it be interpolate?
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yes, it would be. Bad minendo, and bad Evad for not catching that ;)
 
minendo

minendo

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Aug 31, 2001
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Originally posted by: Moonbeam
He might have meant extrapolate if he meant 19F. :D
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I meant interpolate. I would have extrapolated had I only known the densities for 20C and above.

 
Zebo

Zebo

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Jul 29, 2001
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It depends of the type of dissovlved gases in the water and atmospheric pressure. The best way is trought expirmentation on the vessle of water (mass/volume) at the temp in question.

Now the question I have is why 4C is water at it's greatest density;)
 
Evadman

Evadman

Administrator Emeritus<br>Elite Member
Feb 18, 2001
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Originally posted by: Carbonyl
It depends of the type of dissovlved gases in the water and atmospheric pressure. The best way is trought expirmentation on the vessle of water (mass/volume) at the temp in question.

Now the question I have is why 4C is water at it's greatest density;)
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because it expands on both sides of 4C :) Water is special ;)
 
Zenmervolt

Zenmervolt

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Oct 22, 2000
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Originally posted by: Evadman
That's no excuse. I'm a Finance Major and I knew what they were talking about.

ZV
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You are FAR from normal Sir. ;)
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That's what the people in the "Physics for Engineers" courses I took a couple semesters ago said. I figured it would be more fun to take a set "real" Physics courses instead of the "Physical Science" classes that the other Business Majors took. The Engineering Majors thought I was nuts (I think they were secretly upset that a Finance Major could be near the top of the class). :) As the saying goes, "Anything easy has its cost."

ZV
 
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bGIveNs33

Golden Member
Jul 10, 2002
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Originally posted by: Carbonyl
It depends of the type of dissovlved gases in the water and atmospheric pressure. The best way is trought expirmentation on the vessle of water (mass/volume) at the temp in question.

Now the question I have is why 4C is water at it's greatest density;)
Click to expand...

I've only taken 1 college level Chem class but I'm gonna take a guess at it. Water is one of the few things that expands when it freezes(only other one I know is the metal used for the letters in typewriters). So, the closer it gets to its freezing point the water begins to form its hexagonal(i think) shape. And, of course as the temp rises the density decreases because the molecules are moving faster.

edit... LOL... i originally put "I'm gonna take a st@b at it" but with an "a" instead of "@" and it basically said "no soup for you".
 
Zebo

Zebo

Elite Member
Jul 29, 2001
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Originally posted by: bGIveNs33
Originally posted by: Carbonyl
It depends of the type of dissovlved gases in the water and atmospheric pressure. The best way is trought expirmentation on the vessle of water (mass/volume) at the temp in question.

Now the question I have is why 4C is water at it's greatest density;)
Click to expand...

I've only taken 1 college level Chem class but I'm gonna take a guess at it. Water is one of the few things that expands when it freezes(only other one I know is the metal used for the letters in typewriters). So, the closer it gets to its freezing point the water begins to form its hexagonal(i think) shape. And, of course as the temp rises the density decreases because the molecules are moving faster.

edit... LOL... i originally put "I'm gonna take a st@b at it" but with an "a" instead of "@" and it basically said "no soup for you".
Click to expand...

LOL I've wrote STAAAB before on a really long long post and it got lost cuz of the word.

Yes, water should really be wirtten as (h2O)n because of it's very strong hydrogen bonding of water (as you know most other liquids become more dense as they freeze). But water is constantly breaking these bonds and expanding and contracting because of that when above 4C and acts just like any other liqiuid above that temp . But below that, as you apprach freezing, the molecules no longer move vigorously enough to break their picosecond on and off hydrogen bonding. And finally at freezing, all water molecules are "locked" into having four nearest neighbors (crystalline stucture), each positive H atom form a permanet bond with four Oxygens from neighboring water molecules.


 
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