Moderate

30 grams of 2-propanol were mixed with excess acidified K2Cr2O7 and boiled under reflux for 20 minutes. The organic product was then collected by distillation. The yield of product was 75.0%. What is the mass of product produced?

Correct answer: B. 21.75g

  • A. 1.74g
  • B. 21.75g
  • C. 2.74g
  • D. 29 g

Explanation

To calculate the mass of the product produced, you can use the yield percentage. The yield percentage is calculated as follows: Yield (%) = Actual Yield / Theoretical Yield × 100 In this case, the yield is given as 75.0%, and mass of 2-propanol is 30 grams. The molecular formula of 2-propanol (isopropanol) is C3H8O. Molar mass of C3H8O = (3 * 12.01 g/mol) + (8 * 1.01 g/mol) + (1 * 16.00 g/mol) = 60.03 g/mol Theoretical Yield = (Mass of 2-propanol) × (Theoretical Yield / Molar Mass of 2-propanol) Theoretical Yield = (30 g) × (1 mol / 60.03 g) = 0.4999 mol Now, calculate the actual yield using the given yield percentage: Yield (%) = (Actual Yield / Theoretical Yield) × 100 75.0% = (Actual Yield / 0.4999 mol) × 100 Actual Yield = (75.0% / 100) × 0.4999 mol = 0.3749 mol Now, convert the actual yield from moles to grams using the molar mass of the product you expect to obtain. Actual Yield (grams) = 0.3749 mol × 60.03 g/mol = 22.51 g So, the mass of the product produced is approximately 22.51 grams, which is closest to option (b) 21.75g.

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