Percentage yield and atom economy

Percentage yield and atom economy Quiz

Spec 1.9 · Edexcel International A Level Chemistry: Quiz

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  1. 1. What is the atom economy for making O2 in 2KClO3 → 2KCl + 3O2 (K = 39.1, Cl = 35.5, O = 16.0)?

    • A. 19.6%
    • B. 39.2%
    • C. 78.4%
    • D. 100%

  2. 2. A reaction should give 12.5 g of product but 8.00 g is obtained. What is the percentage yield?

    • A. 64.0%
    • B. 156%
    • C. 36.0%
    • D. 4.50%

  3. 3. Which of these would increase the atom economy of a process?

    • A. A catalyst
    • B. Higher temperature
    • C. Choosing a reaction route that makes fewer or lighter by-products
    • D. Using less solvent

  4. 4. 1.215 g of magnesium forms 2.015 g of an oxide. What is the empirical formula (Mg = 24.3, O = 16.0)?

    • A. Mg2O
    • B. MgO2
    • C. Mg2O3
    • D. MgO

  5. 5. In a formula experiment the mass gain of the magnesium is lower than expected because oxide escaped as smoke. How can the experiment be improved?

    • A. Use more magnesium
    • B. Heat to constant mass and keep the lid on as far as possible
    • C. Use a smaller crucible without a lid
    • D. Weigh the crucible only once

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