chloride did the sample contain? 4. FeCl_(3) weighs 5.95 g.The chloride converted to the hydrous oxide and ignited to Fe_(2)O_(3) The oxide weighs 2.62 g Calculate the percent Fe in the original mixture. Calculate the pH and pOH of the following strong base solutions: 0.14 M Ba(OH)_(2)

To calculate the percent Fe in the original mixture, we need to determine the amount of Fe in the final oxide ($Fe_{2}O_{3}$) and then calculate the percentage based on the initial weight of the chloride ($FeCl_{3}$).<br /><br />1. Calculate the molar mass of $Fe_{2}O_{3}$:<br /> - Molar mass of Fe = 55.85 g/mol<br /> - Molar mass of O = 16.00 g/mol<br /> - Molar mass of $Fe_{2}O_{3}$ = (2 × 55.85) + (3 × 16.00) = 159.69 g/mol<br /><br />2. Calculate the moles of $Fe_{2}O_{3}$:<br /> - Moles of $Fe_{2}O_{3}$ = Mass / Molar mass = 2.62 g / 159.69 g/mol = 0.0164 mol<br /><br />3. Calculate the moles of Fe in $Fe_{2}O_{3}$:<br /> - Moles of Fe = 2 × Moles of $Fe_{2}O_{3}$ = 2 × 0.0164 mol = 0.0328 mol<br /><br />4. Calculate the mass of Fe in the original mixture:<br /> - Mass of Fe = Moles of Fe × Molar mass of Fe = 0.0328 mol × 55.85 g/mol = 1.83 g<br /><br />5. Calculate the percent Fe in the original mixture:<br /> - Percent Fe = (Mass of Fe / Initial weight of $FeCl_{3}$) × 100% = (1.83 g / 5.95 g) × 100% = 30.6%<br /><br />Therefore, the percent Fe in the original mixture is 30.6%.<br /><br />To calculate the pH and pOH of the 0.14 M $Ba(OH)_{2}$ solution, we need to use the following formulas:<br /><br />pH = -log[H+]<br />pOH = -log[OH-]<br /><br />1. Calculate the concentration of OH- ions in the $Ba(OH)_{2}$ solution:<br /> - $Ba(OH)_{2}$ dissociates into 2 OH- ions per molecule.<br /> - [OH-] = 2 × 0.14 M = 0.28 M<br /><br />2. Calculate the pOH of the solution:<br /> - pOH = -log[OH-] = -log(0.28) = 0.55<br /><br />3. Calculate the pH of the solution:<br /> - pH = 14 - pOH = 14 - 0.55 = 13.45<br /><br />Therefore, the pH of the 0.14 M $Ba(OH)_{2}$ solution is 13.45, and the pOH is 0.55.