Percentage yield and atom economy

Question 1

Percentage yield

Answer 1

Atoms never lost or gained in a chemical reactions
Not always possible to obtain calculated amount of product

Question 2

Reversible reaction

Answer 2

May not go to completion
Some product could be lost when separated from the reaction mixture

Question 3

What is amount of product called

Answer 3

Yield

Question 4

Percentage yield formula

Answer 4

(Yield from reaction/
maximum theoretical yield)x100

Question 5

Atom economy

Answer 5

Measure of amount of reactant that end up in a useful product
Scientists choose reaction pathways with higher atom economy

Question 6

Atom economy formula

Answer 6

(Relative formula mass of desired product/sum of relative formula mass of all products and reactants)x100

Question 7

Production of ethanol

Answer 7

Hydration and fermentation

Question 8

Hydration

Answer 8

Ethene reacted with steam to form ethanol
C2H4+H2O—->C2H5OH

Question 9

Fermentation

Answer 9

Fermentation of glucose
C6H12O6——->2C2H5OH+2CO2

Question 10

Choosing reaction pathways

Answer 10

Atom economy
Cost of reactants
Percentage yield
Rate of reaction
Equilibrium position
Usefulness of by products