This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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b) (i) How many moles of zinc are there in 2.08 g of anhydrous zinc Sulphate? Step 1: Calculate the molar mass of anhydrous zinc sulfate (ZnSO_4). Given atomic masses: Zn = 65, S = 32, O = 16. Molar mass of ZnSO_4 = Zn + S + (4 × O) Molar mass of ZnSO_4 = 65 + 32 + (4 × 16) = 65 + 32 + 64 = 161 g/mol Step 2: Calculate the moles of anhydrous zinc sulfate. Moles of ZnSO_4 = Mass of ZnSO_4Molar mass of ZnSO_4 Moles of ZnSO_4 = 2.08 g161 g/mol ≈ 0.012919 mol Step 3: Determine the moles of zinc. From the formula ZnSO_4, 1 mole of ZnSO_4 contains 1 mole of Zn. Moles of Zn = Moles of ZnSO_4 Moles of Zn ≈ 0.0129 mol There are approximately 0.0129 mol of zinc in 2.08 g of anhydrous zinc sulfate. (ii) How many moles of water were lost? Step 1: Calculate the mass of water lost. Initial mass of hydrated crystals = 3.715 g Mass of anhydrous zinc sulfate = 2.08 g Mass of water lost = Initial mass - Mass of anhydrous salt Mass of water lost = 3.715 g - 2.08 g = 1.635 g Step 2: Calculate the molar mass of water (H_2O). Given atomic masses: H = 1, O = 16. Molar mass of H_2O = (2 × H) + O Molar mass of H_2O = (2 × 1) + 16 = 2 + 16 = 18 g/mol Step 3: Calculate the moles of water lost. Moles of H_2O = Mass of H_2OMolar mass of H_2O Moles of H_2O = 1.635 g18 g/mol ≈ 0.090833 mol Approximately 0.0908 mol of water were lost. (iii) Determine the value of n in the formula ZnSO_4 · nH_2O. Step 1: Use the moles of anhydrous zinc sulfate and moles of water lost. From part (i), Moles of ZnSO_4 ≈ 0.012919 mol. From part (ii), Moles of H_2O ≈ 0.090833 mol. Step 2: Calculate the ratio of moles of water to moles of zinc sulfate to find n. n = Moles of H_2OMoles of ZnSO_4 n = 0.090833 mol0.012919 mol ≈ 7.03 Rounding to the nearest whole number, n = 7. The value of n is 7. 3 done, 2 left today. You're making progress.