Topic 5 - Separate Chemistry Flashcards
What is a yield?
The amount of product you get from a chemical reaction
What do you mesure the yield in?
Grams/moles
What is an actual yield?
The amount we actually get produced in a chemical reaction.
What is a theoretical yield?
The amount of product you’d expect to get
What are the 3 main reasons that an actual yield is different to the theoretical yield?
- Reactants might not all react
- There could be side reactions
- ## We may loose some of the products.
What does it mean when the reactants dont all react?
Some of the mixture will be reactants.
This could be if the reaction is slow or if the reaction is reversibe.
What does it mean when a chemical reaction has side reactions?
Reactants react to produce a different side product than the one we were expecting. E.g reacting with the air.
How may some products be lost in a chemical reaction?
Gases may diffuse
Filtering may not capture all of the liquid or solid
Why do we calculate the percentage yield?
To tell us what percentage of the theoretical yield we actually got.
What is the equation for percentage yield?
Actual yield / Theoretical yield x 100
What is atom economy?
A measure of how many reactant atoms form a desired product.
How do you calculate atom economy?
Mr of desired products/ Mr of all reactants
What are the 3 factors considered when creating the indsutrial Haber process?
- Cost of extracting and refining raw materials
- Energy costs ( High temp and pressure )
- Have to be able to control conditions to maximise yield but also react at an acceptable rate
How do catalysts affect equilibrium
They do not move equilibrium, however increase rate of reaction wich then in turn icreases the rate that the equilibrium is reached
