Practical key terms Flashcards
Why is a syringe not very precise? What should be used instead?
difficult to read
especially when using dark coloured liquid
instead use graduated pipette or burette
Why are replicates used?
to detect anomalies
Why is judging colours using the eye bad? How can it be improved?
subjective
coloromiter of pH meter
What is the problem with too few intermediate readings?
makes conclusion about trends difficult
take recordings at smaller intervals
Why is insufficent range of the indepedant variable a problem?
difficult to identify a pattern
Why is inconsisten stirring a problem? How is this prevented?
inconsistent range of product formation
automated stirrer or standardise timing of stirring
How is pH controlled?
using a buffer
What should be commented on to determine the validity of results?
- limitations
- uncontrolled variables
- effect of errors
- precision
- accuracy
Why are systematic errors not usually as significant?
occur all the way through the experiment
therefore results have the same error
Why are random errors damaging?
causes results in variation at any time
not easily predicted or controlled
What is qualatative?
yes or no answer
What is quantative and semi-quantative?
quantative uses numbers
semi quantative gives some indication to the amount of a substance
