Practicals Flashcards
In a titration, 0.002 mol dm^-3 potassium manganate is used rather than 0.02. Why?
Larger titre leading to less percentage error.
What affects how big the uncertainty is?
The measuring instrument - what increments does it go up in?
Uncertainty with the procedure (repeat to limit this)
Making a judgement.
How do you calculate the uncertainty of repeated measurements?
How do you calculate percentage uncertainty?
Uncertainty/ measurement x 100
How do you reduce percentage uncertainty?
More sensitive equipment or increase the measurement.
Suggest ways a student could improve the quality of her scientific drawing.
No shading. Only use single lines. Add further labels. Don’t allow label lines to intersect. Add magnification.
How do you find percentage yield when you are given the moles of reactant?
Use moles of reactants to find moles of product. Use actual moles of product / expected moles of product.
Explain why an air bubble increases the final burette reading.
Air bubble takes up volume that would be filled by acid.
