1. Consider the conductance meter and the titration method of determining the salt content of a brine sample. Discuss at least two advantages and two disadvantages of each method.
2. A corrosion technologist pipetted a 50.00 mL sample of an unknown brine and titrated it with 37.64 mL of 0.1024 M silver nitrate solution. Calculate the ppm salt (NaCl) in the sample.
3. If a salty crude sample was analyzed to have 110.6 ppm salts, calculate the pounds of salt per 1000 bbls of crude
can someone give me a push in the right direction, cuz I am totally cluless when it comes to this? like i don't want you to give me the answer just need help knowing what to do... thanks
1. The question isn't quite clear as to what is determined in the titration method vs the conductance method. If the conductance meter is simply one of these "dip in" and read the salt content from a graph, then the meter method is fast (an advantage) but it measures anything and everything in the solution that has any ions to transport the electrons from one electrode to the other (a disadvantage). What about cost? Compare the cost of a titration set up (buret and some indicator) vs the cost of a conductance meter (advantages and disadvantages there, too). Finally, look at the time required to calibrate the titration solutions vs the time required to calibrate the conductance meter. And so on.
2. Personally I don't like to use ppm because there is always some confusion as to whether this is w/v ppm or w/w ppm. In analytical chemistry, we prefer to use mg/L instead of w/v ppm because the density of brines is often not 1.0 g/mL and mg/L can't be misconstrued. Anyway, determine mols Ag^+ used. That is L x M. That many mols of Ag^+ will titrate the same number of mols of Cl^-. Obtain grams NaCl by mols Cl^- (which is same as mole NaCl) x molar mass NaCl = grams NaCl. So that many grams NaCl was in 50.00 mL. Convert that to mg/L and that will be ppm (that is w/v ppm but I think that is what the problem wants bacause there is no density given.) To convert mg/L to ppm an example is: 1.5 mg/L NaCl = 1.5 ppm (of course use your numbers).
3. This is just the reverse of #2. Again, no density is given so ppm PROBABLY means mg/L. So 110.8 ppm will be 110.8 mg/L. You will need to convert a bbl (barrel) to liters and convert 1,000 barrels to liters. Then mg/1000 barrels and convert that to lbs/1000 barrels. By the way, when the problem mentioned "crude" I immediately thought of oil. The problem doesn't say what kind of barrel. If its a barrel of water that is 55 gallons. If it is a barrel used in the oil patch it is 42 gallons. I don't mean for all of this to confuse you but I had about 15 years of experience working with the oil industry on brine samples and I ran into these problems everyday. My biggest problem was trying to tell someone who knew nothing about chemistry that I couldn't give the answer in ppm because they didn't give me the density. And of course, they thought they knew what a ppm was and they didn't know what a mg/L was. (Actually, they didn't know either. :-)
I hope this helps you get started.
2. The moles of silver nitrate will be equal to the moles of sodium chloride.
molesAgNO3= .03764*1.024
then, convert moles sodium chloride to mass, assume 50g H2O in the sample, and compute ppm
ppm= masssalt/50g * 10^6
3) compute the mass of 1000bbls of crude.
110.6= masssalt/masscrude * 10^6
how many atoms of iron are in 0.750 moles of the compound Iron (III) oxide?
1 answer
1 answer