Part 1 Flashcards
Give examples of volume measurements
Conical graduates
Cylindric graduates
pipette
pipette-filling bulb
Give examples of when a conical graduate should be used over a cylindric graduate
When we need to make something “QS”
When we want to mix something in there (wider measuring device. easier than cylindric)
In a pharmacy setting, we usually don’t use pipettes we use ____ instead
syringes
Name the tool with the greatest to least amount of error
(choices: Pipette, conical graduate, cylindric graduate)
greatest error: conical graduate
middle: cylindric graduate
least error: pipette
An error of no more than ______% is considered acceptable
5%
Give 2 examples of equipment used to measure solids
- Torbal torsion balance (double pan)
- Ohaus electronic balance (1 electric pan)
Define accuracy in terms of using a prescription balance
the degree of agreement between the value DISPLAYED on the balance and the TRUE VALUE of the quantity measured
Define calibration
Calibration is the process of adjusting a measuring device to a reference point or standard unit of measure
Calibration is critical to _____
accuracy
When should calibration be verified?
calibration is normally done on most balances during manufacture. However, calibration should be measured at INSTALLATION and performed periodically to maintain accuracy
are some balances self calibrating?
yes
When must calibration be done every time the equipment is used?
when a double pan is being used
Define load
the weight applied to the receiving balance or scale
Define precision
the degree of agreement between repeated measures of the same quantity
Define readability
the smallest fraction of a division to which a balance or scale can be read
What is sensitivity requirement ?
The load (weight) that will cause a change of one division on the index plate on a balance
What is stability
the degree of constancy of measurement of an instrument when subject to variation in external factors such as time, temperature, and supply voltage
Name 3 methods to test a balance
-arm ratio test
-shift tests
-rider and graduated beam test
Briefly explain the procedure of using a prescription balance and give the alternate name for a prescription balance
prescription balance = double pan torsion balance
Drugs go on the LEFT, weights go on the RIGHT
Weighing boats or papers must always be used
Weights should not be left on the balance when not in use
Must be LOCKED during weighing operations (otherwise it will swing)
A prescription balance (AKA double pan torsion balance) is known as a ___ class balance
Class A balance according to the USP
Class III balance according to NIST (national institute for standards and technology)
Are weights used in a top loading balance?
no
What is the sensitivity requirement of a prescription balance
6mg
Describe what a top-loading balance is
a SINGLE pan with internal weights and digital display features
