Seawater contains 3.4 g of salts for every liter of solution. Assuming that the solute consists entirely of NaCl (over 90% is), calculate the osmotic pressure of seawater at 23°C.
By using the formula osmotic pressure=(molarity)(temperature)(R), I got this...
1. M=mol/L=(3.4/58.4)/1 [because it says per liter]
2. T=23+273=296
3. MTR=1.41
...but the answer I got was wrong, so I tried multiplying the moles by .9 (thinking the 90% part was important), but the answer was still wrong. Any ideas?
2006-12-30 08:07:00 · 2 answers · asked by SDesign 1 in Science & Mathematics ➔ Chemistry
I never thought of that, but thanks so much! Both answers were GREAT :)
2006-12-31 09:52:48 · update #1
Try thinking along the lines of NaCl having two particles, Na+ and Cl- ions.
So try doubling the number of moles of NaCl to get the total number of moles of particles.
2006-12-30 08:53:28 · answer #1 · answered by Gervald F 7 · 0⤊ 0⤋
First the 90 is a red herring. The problem says assume it is all NaCl. You have left out the von't Hoff factor (for NaCl, 2 ions per mole). The equation is iMRT, not MRT.
2006-12-30 17:34:03 · answer #2 · answered by Peter Boiter Woods 7 · 0⤊ 0⤋