6.9 Atom Economy

Question 1

What does the atom economy of a reaction tell you?

Answer 1

How much of the mass of the reactants is wasted when manufacturing a chemical and how much ends up as desired products

Question 2

What is the atom economy equation?

Answer 2

atom economy = relative formula mass of desired products/relative formula mass of all reactants x 100

Question 3

The higher the atom economy the ‘________’ the process

Answer 3

Greener

Question 4

Why is it important to consider atom economy? (3)

Answer 4

• Raw materials are expensive, so if they’re mostly being converted into waste products the process is generally going to be less profitable
• Reactions with low atom economy use up resources very quickly to make tiny amounts of products. This means the reaction is less sustainable
• At the same time, they make lots of waste materials that have to be disposed of somehow. That tends to make these reactions unsustainable - non-renewable raw materials will run out and the waste has to go somewhere

Question 5

What are 2 alternatives for using low atom economy reactions?

Answer 5

• Use a reaction with a high atom economy
• You can find a use for the waste products rather than just throwing them away. There’s often more than one way to make the product you want, so the trick is to come up with a reaction that gives useful by-products rather than useless ones. Even if you cant sell these useful by-products for very much money, its still much better than paying to dispose of the waste

Question 6

What are the reactions with the highest atom economy?

Answer 6

The ones that only have one product. Those reactions ave an atom economy of 100%

Question 7

What are the 5 other important factors that depend how profitable a reaction is?

Answer 7

• % Yield
• Cost of raw materials
• The position of equilibrium
• The rate of reaction
• Cost of maintaining the right conditions