C5.1 Flashcards
What is yield
The mass of the product made in a chemical reaction
What is theoretical yield
The maximum mass possible to make from a given mass of reactants.
How to work out theoretical yield
Use mole calculations (stoichometry)
What is actual yield
The actual mass of product you make in a chemical reaction
What is percentage yield
Percentage yield = actual yield/theoretical yield x 100
What are the factors that affect percentage yield
. The reactant may react in a different way than expected
. The reaction may not go to completion
. You may lose some product when separating and purifying it
What is atom economy
atom economy = sum of Mr of desired products/sum of Mr of all products x 100
What are the different factors that are considered when choosing a reaction pathway
Yield of the product
Atom economy of the reaction
Usefulness of by-products
Rate of reaction
Equilibrium position if it’s a reversible reaction
What is a by-product
Is a substance formed in a reaction in addition to the desired product. If it’s useful it’s considered in the atom economy.
How many cm cubed in a dm cubed
1000
What is the formula for concentration in (mol/dm cubed)
Concentration (mol/dm cubed) = mass of solute (mol) /volume of solution in (dm cubed)
What is the formula for concentration in (g/dm cubed)
Concentration (g/dm cubed) = mass of solute (g) /volume of solution in (dm cubed)
What is in the conical flask in a titration
In a titration you have a known volume of alkali or acid in the conical flask with an indicator such as phenolpathein.
What do you do to the tap in a titration
You need to let it flow until there is a slight colour change then add it drop by drop until it changes colour completely (whilst swirling).
What is the end point in a titration
The end point in a titration is when the alkali has been neutralised/ changed colour.
What do you repeat titrations until you have
You repeat titration until you have at least 2 concordant titres.
What are concordant titres within of each other
0.10 cm cubed of each other
what are the precautions that you need to take during titrations
You should use a volumetric pipette to work out the volume of the solution;.
You need a pipette filler to use a volumetric pipette safely
What must be clamped vertically to obtain accurate readings
The burette
What does one mole of any substance in the gas state do
It occupies the same volume at the same temperature and pressure
gas moles
24 = volume/mol
