80. From 0.5100 g of ore, after a series of operations, copper was transferred into solution in the form of a copper (II) salt. When an excess of potassium iodide was added to this solution, iodine was released, which was titrated with 14.10 ml of sodium thiosulfate Na-2-S-2O3 * 5H2O with a copper titer of 0.006500 g / ml. What percentage of copper does the ore contain?

If you do not open the file - install the RAR archiver. Inside the archive you will find a solution in Word format.