Posted by Riana on Tuesday, January 29, 2013 at 6:03pm.
25g of NaCl is deissolved in 100g of water. what is the concentration in percentage by mass?

chemistry  Riana, Tuesday, January 29, 2013 at 6:17pm
and mol/l ?( the density of the solution is 1.15g/ml)

chemistry  Devron, Tuesday, January 29, 2013 at 9:51pm
Question 1
Percent by mass of the solution= mass of NaCl/total mass= 25g of NaCl/25 g of NaCl +100g of H2O
Question2
Density =mass/volume, solve for volume
Solve for moles
moles of NaCl=25g of NaCl/58.44 g of NaCl/mol
Solve for Volume
mass/density=volume=125g of total solution/1.15g/ml=volume of total solution
The units for volume are in mL, so multiply that by 10^3 to convert to L.
Molarity=moles/Liters=moles of NaCl/volume of total solution (L)