Atom economy ppt.pptx..............................................

ATOMS

1. Atom Economy Hydrogen can be made by passing steam over heated coal (carbon): C + 2H 2 O → 2H 2 + CO 2 In this process we WANT the hydrogen, and the CO 2 is a by-product. Is this reaction efficient ?

2. All of the carbon goes to waste! C + 2H 2 O → 2H 2 + CO 2 But just how inefficient is it? You could say that 3 in 7 atoms gets wasted. THIS IS NOT THE ATOM ECONOMY! The different atoms do not have equal weighting. Atom Economy

3. C + 2H 2 O → 2H 2 + CO 2 12 + 2x18 → 2x2 + 44 What is the total mass of substance going into the reaction (per mole)? What is the total mass of desired reactant produced (per mole)? What is the total mass of substance wasted (per mole)? Atom Economy

4. C + 2H 2 O → 2H 2 + CO 2 12 + 2x18 → 2x2 + 44 What is the total mass of substance going into the reaction (per mole)? 48 What is the total mass of desired reactant produced (per mole)? 4 What is the total mass of substance wasted (per mole)? 44 Atom Economy

5. C + 2H 2 O → 2H 2 + CO 2 12 + 2x18 → 2x2 + 44 What is the total mass of substance going into the reaction (per mole)? 48 What is the total mass of desired reactant produced (per mole)? 4 What is the total mass of substance wasted (per mole)? 44 Atom Economy % atom economy = 4/48 x 100 = 8.3% Now write a GENERAL equation for % atom economy!

6.   Definitions You need to know the balanced chemical equation. What is the difference between atom economy and percentage yield?

7. Percentage Yield = the actual yield expressed as a percentage of the theoretical yield. (Can vary based on scientist, or how the experiment is carried out). Atom Economy = the theoretical efficiency of a chemical process. (Does not vary based on how the experiment is carried out, only if the equation varies). Definitions

8. Answer = 111.7/243.7*100 = 45.8% Answer = 100% Answer = 63.02/81.04*100 = 77.8%

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