Including this datum results in an overall standard deviation that is statistically different than that obtained with the rejected datum. We solve the K sp equation for the molar solubility, x Now find the weight in the 0.030 M chloride solution 4. A 0.5962 g iron ore sample was dissolved in hot perchloric acid and then filtered. The solution was made basic with ammonium hydroxide, NH 4 OH, and the iron subsequently precipitated as ferric hydroxide. This gel was filtered in a cistern-glass crucible, rinsed with dilute ammonium hydroxide, ignited, cooled in a desiccator, and weighed.
Ammonium hydroxide is a volatile electrolyte solution.
The original counter ions should be eliminated to avoid gravimetric errors. The desiccator is used to keep the sample dry. Its use during cooling avoids weight gain due to water adsorption. Calculate the weight percent iron in the ore. Regression values for the slope and intercept, and their standard deviations, are given in the inset box.