Mettler Toledo Density Determination Kit Mode D'emploi page 10

Legend
ρ Density of samples
A Weight of sample in air
B Weight of sample in the auxiliary liquid
ρ Density of auxiliary liquid
0
ρ Air density (0.0012 g/cm
L
α Balance correction factor (0.99985). It takes air buoyancy of the adjustment weight into account.
4.1.2 Density determination of liquids
The density of a liquid is determined using a sinker of known
volume. the sinker is weighed in air and then in the liquid whose
density is to be determined. The density ρ can be determined from
the two weighing results.
With and electronic balance it is possible to determine the weight of
the displaced liquid P (P = A - B), and thus the buoyancy, allowing
the preceding formula to be simplified.
Legend
ρ Density of liquid
A Weight of sinker in air
B Weight of sinker in the liquid
V Volume of sinker
ρ Air density (0.0012 g/cm
L
α Balance correction factor (0.99985). It takes air buoyancy of the adjustment weight into account.
P Weight of displaced liquid (P = A - B)
4.2 Determine density of solids
To improve the accuracy of the result, take following precautionary measures into account:
• The effect of temperature on liquids can cause density changes of order of magnitude 0.1 to 1 ‰ per °C. To
obtain accurate results, take the temperature of the auxiliary liquid into account in all density determinations.
• Adhesion of the auxiliary liquid to the suspension wires of the basket causes an apparent weight increase of up
to 3 mg. If the greatest possible accuracy is required, use a few drops of the wetting agent supplied.
• To avoid air bubbles, take following precautionary measures into account:
– Use enclosed wetting agent or organic liquids. The density change on the addition of wetting agent can
be neglected.
– Degrease solvent-resistant solids.
– Clean basket at regular intervals.
– Gently move basket on first-time immersion to dislodge any air bubbles.
– Remove adhering air bubbles with a fine brush.
Attention
Always wear cloves when touching parts, which are immersed in liquid.
Note
For the density determination of solids, use the broader glass beaker ø 80 mm.
8 Operation
3
)
3
)
Density:
A-B
+ ρ
ρ α
=
L
V
Density simplified:
P
+ ρ
α
ρ
=
L
V
Density Determination Kit