Is the answer 342g? I'm wondering if I am doing this correctly. Also....how many moles/liter are present in a 2 molal solution of HCl? I'm guessing it's not quite as simple as 2 moles/1L. Could someone confirm please? Lastly....how many grams/liter are present in a 2 molal solution of HCl? Is it 72.9g/L?
Any help is much appreciated!
Thank you!
Any help is much appreciated!
Thank you!
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this is a molality problem and not a molarity problem let me take another look
Molality is the concentration of a solution expressed in moles of solute per kg solvent.
if you have a 1 Molal Sucrose solution you have a total mass of 1kg water + 342 g of sucrose. The total mass of the sucrose and solution would be 1.342 Kg for every 1000ml of water because 1000ml = 1 L = 1kg for water. So the amount of grams would be 1342 in 1000ml of 1 molal sucrose solution.
It is not as simple as you would think. for the HCL problem if you had 1kg solvent (water) and you added 2 Molal solution of HCl it would have 2 moles of HCl/kg of solvent. So it would have the 1 kg and the 72.9 grams from the 2 moles of HCl for a total mass of 1072.9 grams in the solution.
Good luck with this. I still think your professor needs to express how many kg of solvent was used to make the solution; or he should ask what are the grams of solute in a a 2 molal solution of a particular solute and what amount of solven is expressed. Maybe he is using this question as an important tool to teach his students that they cannot find the answer if the do not know the amount of solvent too.
Molality is the concentration of a solution expressed in moles of solute per kg solvent.
if you have a 1 Molal Sucrose solution you have a total mass of 1kg water + 342 g of sucrose. The total mass of the sucrose and solution would be 1.342 Kg for every 1000ml of water because 1000ml = 1 L = 1kg for water. So the amount of grams would be 1342 in 1000ml of 1 molal sucrose solution.
It is not as simple as you would think. for the HCL problem if you had 1kg solvent (water) and you added 2 Molal solution of HCl it would have 2 moles of HCl/kg of solvent. So it would have the 1 kg and the 72.9 grams from the 2 moles of HCl for a total mass of 1072.9 grams in the solution.
Good luck with this. I still think your professor needs to express how many kg of solvent was used to make the solution; or he should ask what are the grams of solute in a a 2 molal solution of a particular solute and what amount of solven is expressed. Maybe he is using this question as an important tool to teach his students that they cannot find the answer if the do not know the amount of solvent too.