Green Chemistry Metrics: Atom Economy, E-Factor and Solvent Choice · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Yield hides waste, metrics reveal it

Science · Chemistry · ages 20-21
Name ______________________   Date ____________

  1. What does the E-factor count?

    • The lab electricity bill
    • Waste actually produced per product made
    • The exam score

  2. What does atom economy count?

    • What fraction of reactant mass lands in the product
    • The price of glassware
    • The number of lab workers

  3. Why does an addition route beat a substitution route on atom economy?

    • It runs at night
    • It uses prettier flasks
    • Nearly all atoms join the product

  4. Two routes share a 90 percent yield, but one dumps twice the solvent. Which wins on waste?

    • They tie, yields match
    • The low-solvent route wins
    • Yield decides alone

  5. Reactants total 125 grams, product is 100 grams. Give the atom economy in percent.

    Answer: ______________

  6. Solvent is usually the largest contributor to the E-factor.

    Circle one:   True   False

  7. A reclaimable benign solvent beats a nasty one you must burn, all else equal.

    Circle one:   True   False

  8. Two published routes share similar yields. How do you argue for one on waste?

    • Pick the one with more steps
    • Pick the older paper
    • Compare atom economy and E-factor, then rank the solvents
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Yield hides waste, metrics reveal it W1-mt_sxO1hLpaUV-s1

  1. Waste actually produced per product made · Real waste over real product, from the stated procedure.
  2. What fraction of reactant mass lands in the product · It is a paper ratio of product mass to reactant mass.
  3. Nearly all atoms join the product · No leaving group means little mass is lost as waste.
  4. The low-solvent route wins · Yield hides waste, and solvent dominates the E-factor.
  5. 80 · 100 over 125 is 0.8, which is 80 percent.
  6. True · Reaction and wash volumes dwarf the other piles.
  7. True · Hazard, recovery, and disposal decide between solvents.
  8. Compare atom economy and E-factor, then rank the solvents · Yield ties, so metrics and solvent choice break it.
Worksheet · LightMySky