Chemistry Percentage Yield and Atom Economy Key Terms

Key terms that when revised will help you understand the concept of percentage yield and atom economy. 

HideShow resource information
  • Created by: Molly
  • Created on: 27-04-13 15:47
What is meant by the theoretical yield?
The mass of product that should be made in a reaction if no products are 'lost'.
1 of 14
What is the percentage yield?
The actual amount of product that you collect written as a percentage.
2 of 14
What is the equation for percentage yield?
Actual Yield / Theoretical Yield X 100
3 of 14
What does the percentage yield tell you about a reaction?
Tells you how wasteful the process is as the equation is based on how much of the product is lost because of purification, losses during collection etc.
4 of 14
What is the atom economy of a reaction?
It is a measure of the proportion of the reactant atoms that become part of the desired products in the BALANCED chemical equation.
5 of 14
What is the equation for atom economy?
Atom Exconomy = MR of desired product / MR of all products x 100
6 of 14
What is the atom economy in an addition reaction and why?
The atom economy is ALWAYS 100% because the reactants combine to form a SINGLE product and so no atoms are wasted.
7 of 14
What is the atom economy in a substitution reaction and why?
The atom economy is ALWAYS less than 100% because there are bi products that are made as the atoms from one reactant are swapped with atoms of the other reactant, and so substitution reactions are more wasteful.
8 of 14
Why do companies in the chemical industry choose to use reactions with high atom economies?
Because high atom economy has HIGH environmental and economic benefits.
9 of 14
Why do companies in the chemical industry try to avoid reactions with low atom economies?
Because low atom economy means there is a lot of waste product. It also takes money to seperate the desired product from ALL of the products and more money to dispose of the unwanted products safely so they do not harm the environment.
10 of 14
What helps to solve some of the problems of low atom economy?
By finding other uses for the bi-products so they are not wasted.
11 of 14
Why are reactions with LOW atom economies less sustainable?
Because many raw materials are in low supply and so they need to be used efficiently rather than wasted.
12 of 14
Does the percentage yield for a reaction always have the same value as the percentage atom economy?
No.
13 of 14
Changing conditions such as temperature and pressure will alter the percentage yield. Will changing these conditions affect the atom economy?
No, because atom economy is based on the equation and the proportion of desired product in the entire product.
14 of 14

Other cards in this set

Card 2

Front

What is the percentage yield?

Back

The actual amount of product that you collect written as a percentage.

Card 3

Front

What is the equation for percentage yield?

Back

Preview of the front of card 3

Card 4

Front

What does the percentage yield tell you about a reaction?

Back

Preview of the front of card 4

Card 5

Front

What is the atom economy of a reaction?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Calculations resources »