[altoradoom]

everywhere i read

weight X grams of solute(solid) and fill the measuring to Y ml

what if we have Yml of solvent and add x grams of solute?

will we have diferent concentrations? (in the cases under saturation point of course)

if so why? i always thought that the solute gets in the space between the solvent molecules.

thanks in advance

[Borek]

If the solution is saturated and in equilibrium with solid it doesn't matter. Otherwise you have to take into account volume changes, and they make the difference.

100.0g NaCl filled to 1000 mL - solution volume 1000 mL, solution density 1.0661, molarity 1.7111, 9.3803 w/w %

100.0g NaCl added to 1000 mL - solution volume 1034 mL, solution density 1.0640, molarity 1.6550, 9.0909 w/w %

Play with CASC.

[altoradoom]

100.0g NaCl filled to 1000 mL - solution volume 1000 mL, solution density 1.0661, molarity 1.7111, 9.3803 w/w %

100.0g NaCl added to 1000 mL - solution volume 1034 mL, solution density 1.0640, molarity 1.6550, 9.0909 w/w %

first of all thanks,


after searching a bit:  NaCl density 2.16g/cm^3 
thus 100g take a volume of 46,29 cm^3 of NaCL
 solution volume 1034  you gave is 1034

why not 1000 or 1046,29 

i don't need the formulas, i just need to understand the principle.

also, another thing, the final volume of 1000 should be filled after the dissoluton, right? if one fills before mixing for dissolving, and then mixes the final volume will be under the 1000, right?

took a look at CASC seems insteresting, downloaded  demo and played a while, very interesting!

[Borek]

solution volume 1034  you gave is 1034

why not 1000 or 1046,29 

i don't need the formulas, i just need to understand the principle.

No principle here

The only principle is that volumes are not additivie and it is in practice impossible to precisely calculate solution volume without using density tables (that's what CASC does). In other words: we can't calculate, we can only measure.

took a look at CASC seems insteresting, downloaded  demo and played a while, very interesting!

Try EBAS and BATE as well.