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### Topic: what is the molarity of water?  (Read 22759 times)

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#### doubt

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##### what is the molarity of water?
« on: May 16, 2007, 02:53:01 AM »
My Question is

"What is the molarity of Water?"

can you please explain me the answer clearly with an small explanation

since i'm not an chemical student...but wish to know the molarity of water

thank you very very much in advance.

#### Borek

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##### Re: what is the molarity of water?
« Reply #1 on: May 16, 2007, 03:04:56 AM »
Simply start with molarity definition - all you have to do is to plug numbers
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#### Dolphinsiu

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##### Re: what is the molarity of water?
« Reply #2 on: May 16, 2007, 03:18:40 AM »
Molarity means concentration.

For example, molarity of NaCl solution = concentration of NaCl solution

#### AWK

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##### Re: what is the molarity of water?
« Reply #3 on: May 16, 2007, 03:33:23 AM »
How many moles of H2O are in 1 liter of water?
AWK

#### english

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##### Re: what is the molarity of water?
« Reply #4 on: May 16, 2007, 03:00:18 PM »
Think about water's density, and what the units signify.  The answer lies there.

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##### Re: what is the molarity of water?
« Reply #5 on: May 16, 2007, 05:01:49 PM »
well, the molarity of water is a tricky one, as usually we take water as solvent and are interested only in the molarity of the solute.

Basic explanation is as Borek referred to:
Molarity = number of moles per unit volume.

Now with the molarity of water you have to go to the basics:
-The density (r, Temperature dependant!) will give you the number of grams per dm3
-The molar mass (M, in g/mol) will allow you to calculate mass (grams) into moles.

So: r / M
will give you number of moles/dm3 = molarity

#### AWK

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##### Re: what is the molarity of water?
« Reply #6 on: May 17, 2007, 01:13:04 AM »
Think about water's density, and what the units signify.  The answer lies there.
For molarity, density is not needed
AWK

#### english

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##### Re: what is the molarity of water?
« Reply #7 on: May 17, 2007, 10:07:18 AM »
Think about water's density, and what the units signify.  The answer lies there.
For molarity, density is not needed

Yes but it's easier.  If you have x L of water and we assume that its density is approx. 1 g/mL, or 1 kg/L, then you know how many grams of water are in x L of water.

Denisty of water is such a commonality that I see it as the easiest way.

#### ARGOS++

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##### Re: what is the molarity of water?
« Reply #8 on: May 18, 2007, 11:58:01 AM »

Dear GWK,  Dear All,

Sorry, but now I believe, that something went wrong!!

DONNOT intermix MolaLity with MolaRity, NEVER !!!

MolaLity is a MASS-Conzentration!
MolaRity is a VOLUME-Conzentration!
That means, that MolaRity MUSST very strongly depend on the Density of the Solvent you use.

But for theThumb-Rule” it is allowed to set the Density of Water to 1.00 g/cm3,
what results in the simple Division of: 1000g / “MW of Water”,
with the “Schnaps-Zahl” of  55.55  !!!

Good Luck!
ARGOS++