2. Concentration of metal ion. Absorbance of metal ion in solution 0.316 Concentration of metal ion from the calibration curve (mol/L) 0.084 Concentration of metal ion in the original sample corrected for dilution (mol/L) Show your calculations to account for the dilution of the original sample.

In most of its ionic compounds, cobalt is either Co(II) or Co(III). One such compound, containing chloride ion and waters of hydration, was analyzed, and the following results were obtained. A 0.256-g sample of the compound was dissolved in water, and excess silver nitrate was added. The silver chloride was filtered, dried, and weighed, and it bad a mass of 0.308 g. A second sample of 0.416 g of the compound was dissolved in water, and an excess of sodium hydroxide was added. The hydroxide salt was filtered and heated in a flame, forming cobalt(III) oxide. The mass of cobalt(III) oxide formed was 0.145 g. a. What is the percent composition, by mass, of the compound? b. Assuming the compound contains one cobalt ion per formula unit, what is the formula? c. Write balanced equations for the three reactions described.

Twenty-five milliliters of a solution (d=1.107g/mL)containing 15.25% by mass of sulfuric acid is added to 50.0 mL of 2.45 M barium chloride. (a) What is the expected precipitate? (b) How many grams of precipitate are obtained? (c) What is the chloride concentration after precipitation is complete?

An experiment in a general chemistry laboratory calls for a 2.00-M solution of HCl. How many mL of 11.9 M HCl would be required to make 250 mL of 2.00 M HCl?

Two liters of a 1.5 M solution of sodium hydroxide are needed for a laboratory experiment. A stock solution of 5.0 M NaOH is available. How is the desired solution prepared?

Two students titrate different samples of the same solution of HCl using 0.100 M NaOH solution and phenolphthalein indicator (Figure 4.12). The first student pipets 20.0 mL of the HCl solution into a flask, adds 20 mL of distilled water and a few drops of phenolphthalein solution, and titrates until a lasting pink color appears. The second student pipets 20.0 mL of the HCl solution into a flask, adds 60 mL of distilled water and a few drops of phenolphthalein solution, and titrates to the first lasting pink color. Each student correctly calculates the molarity of an HCl solution. What will the second students result be? (a) four times less than the first students result (b) four times greater than the first students result (c) two times less than the first students result (d) two times greater than the first students result (e) the same as the first students result

95. Many metal ions form insoluble sulfide compounds when a solution of the metal ion is treated with hydrogen sulfide gas. For example, nickel(II) precipitates nearly quantitatively as NiS when H2S gas is bubbled through a nickel ion solution. How many milliliters of gaseous H2S at STP are needed to precipitate all (he nickel ion present in 10. mL of 0.050 M NiCl2 solution?

What volume of 0.0105-M HBr solution is required to titrate 125 mL of a 0.0100-M Ca(OH)2 solution? Ca(OH)2(aq)+2HBr(aq)CaBr2(aq)+2H2O(l)

A 25-mL sample of 0.50 M NaOH is combined with a 75-mL sample of 0.50 M NaOH. What is the concentration of the resulting NaOH solution?

A solution is formed by mixing 1 gal ethanol with 10 gal gasoline. Identify the solvent and the solute.