What Are the Methods for Calculating Concentration of a Mass in a Solution?

[Kelly09]

Hi guys,here is my question. What is the Concentration of Na2CO3 when it dissolves in a solution and forms a volume of 100 cubic cm?

Concentration= moles/volume.
I found moles using mass/atomic mass of Na2+C+03.
Then i used moles/volume to calculate concentration. Correct?

 

[Kelly09]

Mass of Na2CO3 is 5.8g

 

[sjb-2812]

So far so good.

 

[Kelly09]

I found concentration to be 0.0005M. Could you confirm if this is correct?

 

[sjb-2812]

Sounds a bit low to me, can you show your working?

 

[Kelly09]

Concentration=moles/volume

Moles = mass/atomic mass, 5.8g/Na2C03

So 5.8/106=0.005moles.

Conc=0.05/100=0.0005M. So?

 

[sjb-2812]

What is the definition of M here?

 

[Kelly09]

M is concentration. There are two ways of writing it,M or mol/dm3

 

[sjb-2812]

OK, so how many dm³ are there in your solution?

 

[Kelly09]

0.0005mol/dm3

 

[Char. Limit]

No... what you'd get in your calculations is 0.0005 mol/cm^3. You should change your mL (cm^3) to L (dm^3) before using it.

 

[Borek]

OK, so how many dm³ are there in your solution?

0.0005mol/dm3

sjb asked about volume of the solution, and you have answered giving concentration...

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methods