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plz i need question 8 might have happened to cause your percentage to be high or

ID: 548126 • Letter: P

Question

plz i need question 8

might have happened to cause your percentage to be high or low) 8 Would your experimental percent sulfate be high or low if your alum sample had a soluble non-sulfate impurity, for example, water? To prove your answer, do the following calculation. Assume that included in the weight of a sample of alum are 0.10 g of water. The total weight of sample is 1.20 g. Calculate the percent sulfate in the sample. 9 Would your experimental percent sulfate be high or low if you spilled a little barium sulfate? Explain. 10 Would your experimental percent sulfate be high or low if the barium sulfate were incompletely washed? Explain. 11 Would your experimental percent sulfate be high or low if the barium sulfate were incompletely dried? Explain.

Explanation / Answer

mass of sample = 1.2 g

Mass of water present in sample = 0.1 g

Mass of pure alum = 1.2 g - 0.1 g = 1.1 g

Molar mass of alum = 474.4 g/mol

No. of moles of alum = (Mass of alum /Molar mass of alum) = 1.1 g / 474.4 g/mol

each mole of alum contains 2 moles of sulfate ion

No. of moles of sulfate ion = 2 * No. of moles of alum = 2 * 1.1 / 474.4 mole

Molar mass of sulfate ion = 96 g/mol

Mass of sulfate = (2 * 1.1 / 474.4) mol * 96 g/mol = 0.445 g

Percent sulfate in sample = (0.445 / 1.1) * 100 = 40.47 % Answer