Sea water contains an average of 270 ppm of sulfate ion. Calculate the molar concentration of sulfate given that the average density of sea water is 1.02 g/ml.
-At first i tried assuming that density is 1.00 g/ml which is a common practice in ppm problems but the answer is wrong. What keeps bugging me is the sea water density because I don't know what to do in terms of using it. Any ideas?
To calculate the molar concentration of sulfate in sea water, you need to consider the density of sea water. Here's how you can approach the problem:
1. Convert the parts per million (ppm) value to grams per liter (g/L), since molar concentration is commonly expressed in moles per liter (mol/L).
To do this, you need to know the molar mass of sulfate ion (SO4^2-) which is 96.06 g/mol.
So, if sea water contains 270 ppm of sulfate ion, it means there are 270 grams of sulfate in every 1 million grams (or 1 million milligrams) of sea water.
To convert to grams per liter, assuming sea water density is 1.02 g/mL:
270 ppm = (270 mg/L) * (1.02 g/mL) * (1 L/1000 mL) = 0.2754 g/L
2. Convert the mass of sulfate to moles.
To do this, divide the mass of sulfate by its molar mass:
0.2754 g/L / 96.06 g/mol = 0.002866 mol/L
So the molar concentration of sulfate ion in sea water is approximately 0.002866 mol/L.