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Topic: Finding Density of a liquid with limited information  (Read 5918 times)

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Offline cnv22

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Finding Density of a liquid with limited information
« on: December 02, 2016, 01:28:16 PM »
How do I figured out the density asked for in this question?

A flask weighs 43.50 g when it is empty, and 105.50 g when filled with water. When the same flask is filled with another liquid, the mass is 96.75 g. What is the density of the second liquid?

Offline Borek

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Re: Finding Density of a liquid with limited information
« Reply #1 on: December 02, 2016, 01:47:19 PM »
What can you calculate from the given information?
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Offline KungKemi

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Re: Finding Density of a liquid with limited information
« Reply #2 on: December 02, 2016, 07:56:01 PM »
Remember that all information given in this question is relevant. One extra thing that I would have added to this question is "Assume that the density of water is 1.00 g/mL."

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Offline Vidya

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Re: Finding Density of a liquid with limited information
« Reply #3 on: December 03, 2016, 06:27:54 AM »
How do I figured out the density asked for in this question?
[/b]
Do you know what is density?
Do you know density of water?
How can first information about water helps in solving density for liquid?

Offline cnv22

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Re: Finding Density of a liquid with limited information
« Reply #4 on: December 03, 2016, 09:38:30 AM »
I know that the mass of the water is 62 g, and that the mass of the unknown liquid is 53.25 g. Is the mass of water being 1.00 g/mL just a standard concept? I am very new to chemistry! I do understand the relationship D=M/V. I can't figure out how to calculate the volume of either liquid with just knowing the mass of the liquid.

Offline Vidya

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Re: Finding Density of a liquid with limited information
« Reply #5 on: December 03, 2016, 09:41:42 AM »
actually the flask is completely filled with water so you can use density of water to calculate volume of water and this volume is equal to volume of the flask.And finally flask volume is also equal to volume of the liquid.I think now you can work out density of liquid.

Offline Dan

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Re: Finding Density of a liquid with limited information
« Reply #6 on: December 03, 2016, 10:55:44 AM »
Is the mass of water being 1.00 g/mL just a standard concept?

Yes, see the definition of gram.
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Offline Arkcon

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Re: Finding Density of a liquid with limited information
« Reply #7 on: December 03, 2016, 12:00:20 PM »
I know that the mass of the water is 62 g, and that the mass of the unknown liquid is 53.25 g.

OK, its often helpful to restate knowns.  So good work here.

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Is the mass of water being 1.00 g/mL just a standard concept?

Since you wrote that, its been confirmed for you several times, in different ways.  So you can just use that.

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I am very new to chemistry!


Not really relevant.  But its OK to mention.  Better at the beginning, or the end, and not stuffed in the middle.

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I do understand the relationship D=M/V.

This is good.  You've been given hints that should have led you here.  But if you know it, you can use it.

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I can't figure out how to calculate the volume of either liquid with just knowing the mass of the liquid.

Interesting.  Don't you have, in one case, the density and mass?  Can't you use that to find volume?  Can't you use the same volume, in the same formula, to find something else unknown? 

What good is D=M/V?   What happens when you plug in what you know, in each case?  That is, D=M/V, replace, in each case the variable, described by a letter, with a value that you know.
« Last Edit: December 03, 2016, 01:33:33 PM by Arkcon »
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Enthalpy

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Re: Finding Density of a liquid with limited information
« Reply #8 on: December 06, 2016, 08:12:57 AM »
Is the density of water being 1.00 g/mL just a standard concept?
This holds for pure water at +4°C. At +25°C it's more like 995kg/m3. Seawater varies a lot, 1030kg/m3 being an example.

The idea behind +4°C is that pure water has its biggest density at this temperature, so a small temperature imprecision around +4°C has smaller consequences than around +25°C.

This tells you too why water deep in the Ocean has +4°C: at that temperature it sinks.

Offline AWK

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Re: Finding Density of a liquid with limited information
« Reply #9 on: December 06, 2016, 09:00:39 AM »


This tells you too why water deep in the Ocean has +4°C: at that temperature it sinks.
This temperature concerns about 2500 m depth. In Mariana Trench temperature is ~+1 C.
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Offline Enthalpy

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Re: Finding Density of a liquid with limited information
« Reply #10 on: December 09, 2016, 06:13:11 PM »
O yes, "+1 to +4°C" according to Wiki
https://en.wikipedia.org/wiki/Mariana_Trench
The pressure or salinity may shift a bit the temperature of maximum density, or the water column isn't at equilibrium, or any other reason.
Thanks, +.

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