{"id":234863,"date":"2025-06-14T14:06:04","date_gmt":"2025-06-14T14:06:04","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=234863"},"modified":"2025-06-14T14:06:06","modified_gmt":"2025-06-14T14:06:06","slug":"first-determine-the-mass-of-sulfate-in-the-sample","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/14\/first-determine-the-mass-of-sulfate-in-the-sample\/","title":{"rendered":"First, determine the mass of sulfate in the sample."},"content":{"rendered":"\n

First, determine the mass of sulfate in the sample. To do this, you need the following information: – Molar mass of SO4^2-: 96.06 g\/mol – Molar mass of BaSO4 (which is your solid precipitate): 233.43 g\/mol Mass of SO4^2- in sample (in g) = (g BaSO4) * (mol BaSO4 \/ 233.43 g BaSO4) * (mol SO4^2- \/ mol BaSO4) This is the mass of your precipitate after oven drying. Second, determine the mass percent of sulfate in the sample: Mass percent of SO4^2- in the sample = (mass of SO4^2- in the sample (in g) \/ mass of original soluble sulfate sample (in g)) * 100 Third, compare your experimental mass percent of sulfate (above) to the mass percentages of sulfate that were calculated in the Procedure in Step #2, page 1. Identify your original soluble sulfate-containing unknown as either Na2SO4, K2SO4, or (NH4)2SO4. Last, evaluate the accuracy of your mass percent sulfate result by calculating a percent error: Percent Error = (|your experimental mass % sulfate – actual mass % sulfate| \/ actual mass % sulfate) * 100<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Correct Answer (Example):<\/h3>\n\n\n\n

Assume the mass of oven-dried BaSO\u2084 precipitate = 0.467 g<\/strong>
Assume the original sample mass = 0.300 g<\/strong><\/p>\n\n\n\n

Step 1: Determine mass of SO\u2084\u00b2\u207b in the sample<\/strong>Mass of SO\u2084\u00b2\u207b=0.467 g BaSO\u2084\u00d7(1 mol BaSO\u2084233.43 g BaSO\u2084)\u00d7(96.06 g SO\u2084\u00b2\u207b1 mol BaSO\u2084)\\text{Mass of SO\u2084\u00b2\u207b} = 0.467\\ \\text{g BaSO\u2084} \\times \\left(\\frac{1\\ \\text{mol BaSO\u2084}}{233.43\\ \\text{g BaSO\u2084}}\\right) \\times \\left(\\frac{96.06\\ \\text{g SO\u2084\u00b2\u207b}}{1\\ \\text{mol BaSO\u2084}}\\right)Mass of SO\u2084\u00b2\u207b=0.467 g BaSO\u2084\u00d7(233.43 g BaSO\u20841 mol BaSO\u2084\u200b)\u00d7(1 mol BaSO\u208496.06 g SO\u2084\u00b2\u207b\u200b)Mass of SO\u2084\u00b2\u207b=0.467\u00d796.06233.43=0.1922 g\\text{Mass of SO\u2084\u00b2\u207b} = 0.467 \\times \\frac{96.06}{233.43} = 0.1922\\ \\text{g}Mass of SO\u2084\u00b2\u207b=0.467\u00d7233.4396.06\u200b=0.1922 g<\/p>\n\n\n\n

Step 2: Determine mass percent of SO\u2084\u00b2\u207b in the sample<\/strong>Mass % SO\u2084\u00b2\u207b=(0.19220.300)\u00d7100=64.07%\\text{Mass \\% SO\u2084\u00b2\u207b} = \\left(\\frac{0.1922}{0.300}\\right) \\times 100 = 64.07\\%Mass % SO\u2084\u00b2\u207b=(0.3000.1922\u200b)\u00d7100=64.07%<\/p>\n\n\n\n

Step 3: Compare to known values for identifying unknown<\/strong><\/p>\n\n\n\n