1 Flashcards
It is defined as mass per unit volume at a fixed temperature and pressure
Density
how is density expressed in CGS system?
g/cm*3
How is density is expressed in the SI unit
kg/m*3
Centimeter
Gram
Second
CGS
Meter
Kilogram
Second
SI
Ratio of a mass of a substance to the mass of an equal volume of another stance chosen or taken as a
Specific Gravity
Formula for Sp.Gr
Ddrug/DH20 (usually standard ang water)
how is specific gravit determined in liquids?
Flotation method
The specific gravity of a liquid maybe determined with the aid of a?
pycnometer
hydrometer
Mohr-Westphal balance
Two types of pycnometer
ordinary
leach
For liquid and solid
Pycnometer
Pycnometer with thermometer
Leach pycnometer
follow principle of bouyance/buoyant effect
Flotation method
Constant weight, Variable depth of immersion of hydrometer-multiple calibration
hydrometer
for light <1g/ml; heavy >1g/mL
Baume hydrometer
Tralle’s hydrometer
Alcoholometer
what hydrometer measure the constant weight, Variable depth of immersion of hydrometer - multiple calibration
Baume Hydrometer
Alcoholometer
Twadell’s hydrometer
Cartier’s hydrometer
what are the hydrometer that pertains the constant depth of immersion variable weight of hydrometer
Nicholson’s hydrometer
Fahrenheit hydrometer
Lovis bead
balloon shaped halo globe of glass with different sizes and weight with specific gravity values scratch on their side
Lovis bead
Fischer Davidson Gravitometer
Manometric method
a very convenient device for taking the specific gravity of liquids
Mohr-Westphal balance
The plimmet (occupying 5mL) suspended from the beam of balance is immersed in the liquid to be tested, in which the plummet is subject to a buoyant effect equivalent to the weight of fluid.
Principle of Mohr-Westphal balance
is measured by placing various weight on the notched beam of the balance to effect submersion of the plummet to a constant reference point
Buoyant force
it is the exert on the plummet is equal to the weight of the liquid displaced
Buoyant effect
What is the principle used in the specific gravity determination of solid pycnometer method
Loss of weight or displacement
is used for most determination of specific gravity of liquid
pycnometer or specific bottle
It maybe ysed in taking specific gravity of solid substances which are small fragments or even in a much finer route of subdivision
Pycnometer
to compute for the specificgravity,what is itsformula
Specific gravity = weight of sample/ weight of standard displaced by solid (spgr of substance)
Weight solid immersed in water
Hydrostatic balance
what is the formula for getting the spgr on hydrostatic balance
spgr = weight of sample/weight of equal volume water
What is the formula for specific gravity if solid heavier than and insoluble in water
Spgr = weight of sample in air/weight sample in air - weight of sample in water
What is the formula if solid heavier than and soluble in water
spgr = weight of sample in air/ weight of sample in air - weight of sample in std liquid x (spgr of standard liquid
Post lab question 1:
the principle involve in specific gravity determination for liquid is buoyant force measured by placing various weights on the notched beam of the balance to effect submersion of the plummet to a constant reference point. Weight displacement is also involved
Post lab question 2:
Specific gravity is the ratio of the substance to the mass of an equal volume of another substance chosen or taken as a standard
Post lab question 3:
Density vs. Specific Gravity
Density:
Concrete Number
Must Vary with the table of measurement
Water maybe variously expressed
Specific Gravity
Ratio between like quantities
Has no dimension therefore a constant value for each subs
H20=1
Post lab question 4:
Methods of determining the specific gravity
Solid
- Pycnometer method (ordinary)
- Hydrostatic balance method
- Graduated cylinder
- Immersion of solid in transparent liquid
Liquid:
Pycnometer method (leach)
Flotation method
Manometric method
