C5.1 Monitoring Chemical Reactions Flashcards
What is theoretical yield?
The maximum mass possible to make from a given mass of reactants
What is yield?
The mass of a product made in a reaction
How do you find theoretical yield?
Just use moles=mass/Mr and stoichiometry.
Whatever you do don’t use the formula, it will just confuse you
What is actual yield?
The amount of product that you actually make
What is percentage yield?
Actual yield/ theoretical yield x 100
What affects percentage yield?
- The reactions may not go to completion, especially if it is reversible
- The reactants may react in a different way to what you thought
- Some product may be lost when separated or purified, eg while filtering
What is Atom economy?
How many atoms in the reactants form a desired product
How do you calculate atom economy?
Sum of Mr of desired products/sum of Mr of all products x 100
What factor determine how you make a substance
- Yield of product
- Atom Economy
- usefulness of by products
- rate of reaction
- equilibrium
What can be done with by products?
By products can sometimes be sold which improves the atom economy. If it is not usable or toxic, nothing can be done with it.
