1.1 Flashcards
What is a risk?
The likelihood that a hazard would cause significant harm
What is a hazard?
The source of potential harm
What is a risk assessment?
Identifying and determining likelihood if harm and implementing measures where necessary
Whats a beaker used for?
General purposes e.g. heating a solvent while the solute dissolves
(50-2000cm3)
How accurate is a beaker?
Not accurate
What is a standard flask?
Flask with a line on the neck to show a very precise volume
(25-1000cm3)
How accurate is a standard flask?
High accuracy
How accurate is a measuring cylinder?
Mid accuracy
How accurate is a pasteur pipette?
Low accuracy
How accurate is an auto-pipette?
High accuracy
How accurate is a syringe?
High accuracy
When is linear dilution used?
Used if you need a sample over a reasonably small range.
For example, 0.1ml, 0.2ml, 0.3ml and so on
What is linear dilution?
When different volumes of concentrated stock solution are added to different volumes of solvent.
What is a benefit of linear dilution?
Each concentration is made individually meaning any errors affect only one concentration
What calculation is used to calculate the concentration in a linear dilution?
C1V1=C2V2
When is log (aka serial) dilution used?
Used when a wide range of concentrations is needed.
Differ by a constant proportion, e.g. 10-1, 10-2, 10-3 and so on
What is log (aka serial) dilution?
Each dilution acts as the stock for the next.
What is a disadvantage of log dilution?
Because each concentration depends on the previous one, any errors are compounded in later dilutions
What is a standard curve?
Is a line or curve produced by plotting measured values for known concentrations.
What can a standard graph be used to estimate?
Unknown concentrations
What is a buffer solution?
A solution whos pH changes very little when small volumes of acid or base is added to it this allows the pH of a reaction mixture to be kept constant
What is the definition of colorimetry?
The use of a colorimeter to quantify concentration of a coloured solution or its turbidity
What is the turbidity of a solution?
Its cloudiness
What is absorbance in a colorimeter?
Used to determine concentrations of coloured solutions
What is the percentage transmission in a colorimeter?
Used to determine turbidity (e.g. cells in a solution)