Chemical Calculations with Moles Flashcards
What is theoretical yield?
The mass of a product that is expected to be produced
Why might theoretical yield be wrong?
- Some product lost when separate from reaction mixture
- Unexpected side reactions
- Reversible reaction
How can theoretical yield be calculated?
Using the balanced symbol equation?
What is yield?
The amount of product actually obtained in a reaction
How do you calculate percentage yield?
(Actual yield/theoretical yield) x 100
What is atom economy?
The proportion of reactant atoms that form useful products
Why are high atom economies more sustainable?
Fewer atoms are wasted in products that are not used
How do you calculate the percentage atom economy?
Atom economy = (Mᵣ of useful products/Mᵣ of all products) x 100
What volume will 1 mole of any gas occupy?
Moles of a gas = volume (dm³)/24dm³
How do you calculate the volume of a gas at room temperature and pressure?
Volume (dm³) = moles x 24dm³
How do calculate concentration? (mol/dm³)
Concentration = number of moles of solute/volume of solution
What is a titration?
An experimental technique to find the concentration of an unknown solution in the reaction between an acid and alkali
What is the process of a titration?
- Using a pipette, extract solution (known volume, unknown concentration)
- Add solution (of unknown concentration) to a conical flask on a white tile
- Add few drops of suitable indicator
- Add other solution (known concentration) to burette
- Carry out rough titration. Add solution from burette to conical flask 1cm³ at a time
- End point - indicator changes colour
- Record volume.
- Repeat but add solution from burette drop-by-drop near end point, swirling conical flask in between drops.
- Record volume at end point. Calculate mean.
What is a titre?
The volume of solution added feom burette
What does a concordant titre mean?
Titres within 0.1cm³ of each other
