Topic5 Flashcards
What is avagadros constant
6.02 x 10 23
What is empirical formula
The simplest whole number ratio of the atoms in a molecule
What is molecular formula
The actual number of atoms of each element
What are ionic equations
Equations that have excluded all the non reacting spectator ions, charge in either side should be equal
What is avagadros law
At the same temperature and pressure one mole of two different gases will have the same volume
This volume is 24dm3
What factors can affect percentage yield
Incomplete reactions
Waste
Extraction
Side reactions
Hydration
How can incomplete reactions change yield
Reaction is to slow
Reaction is reversible some of products have been turned back into reactants
How might waste affect percentage yield
Some of the chemicals will remain stuck to glassware and will be wasted
How will side reactions affect percentage yield
It might be difficult to fully separate product for the reaction mixture.
Why might side reactions affect percentage yield
Unexpected side reactions can happen. This could mean intended product us not created
How might hydration affect percentage yield
If a reaction is carried out in water, any extracted products may be wet, this means their may be water on extracted product. Water is diffcult to remove. If percentage yield is above 100 this may be why
What is atom economy
Desired / total
What is percentage yield
Real /theoretical
What is phenophalen colour change
Colourless to pink
What is methyl orange colour change
Red to yellow
Percentage uncertainty
Uncertainty / measurement
How to reduce uncertainty in titrations
Increase the volume needed by Increasing the tire volume and concentration or by reducing the concentration in the burette
