Specific gravity bottle

The solids density Ps is the density of fhe solid material from which fhe parficle is made and excludes any pore spaces within the particle. It can be measured using a specific gravity bottle and a liquid in which the particle does not dissolve. The envelope density of a particle is that which would be measured if an envelope covered the external particle surface, i.e. it is equal to the particle mass divided by the external volume. In most analyses the envelope and solids densities are assumed to be equivalent. The bulk density of a powder ps is the effective density of the particle bed defined by... 

Volume Changes. The density changes of several amide-water systems have been measured using 10-cc. specific gravity bottles. These experimental values were compared with an ideal density defined in terms of additive molar volumes and are shown as a dotted line in Figures 1 through 8 for the respective amide-water mixtures. 

NOTE Small temperature fluctuations can result in large errors in calculated densities. The temperature of all materials (bottle and solutions) should therefore be carefully controlled during all stages of the procedure using either a temperature-controlled chamber or a water bath. If a water bath is used, all excess water must be wiped off the specific gravity bottle prior to measurements to prevent evaporative cooling effects and errors in weight determination. 

Specific gravity bottle with glass stopper High-precision balance (+1 mg)... 

Measure the weight of an empty specific gravity bottle (mb) using a high-precision balance. 

Fill the specific gravity bottle with continuous phase and measure the new weight of the filled bottle (mt). Calculate the density of the continuous phase (pc) as pc = (m, -... 

Support Protocol Density measurement The required time depends strongly on the equipment being used. Modern analytical equipment can correctly measure density within minutes. If the density measurement is conducted using the specific gravity bottle method, then an initial calibration is required that can take up to several hours (due to the fact that the volume of the bottle has to be determined as a function of temperature). After the initial calibration curve has been obtained, tests can be conducted within 15 to 20 min since only a precise mass determination is necessary. 

The specific gravity of a beer, also termed " present gravity " or attenuation gravity, is determined on the gas-free beer at 15 5° C. (6o° F.)—with reference to water at the same temperature—by means of a specific gravity bottle or a Westphal balance (see Spirits). 

For non-porous solids the particle density is equal to the true, skeletal, or absolute density, Pabs which can be measured using either a specific gravity bottle or air pycnometer ... 

An equivalent formula fpr powders that are present as slurries in water removes the necessity for drying out the slurry. A specific gravity bottle is filled with water and weighed the water is replaced with the slurry under test and the bottle is re-weighed the difference in weights being AIV. The sample is then taken out of the bottle and used for the analysis. The equivalent formula is ... 

A twin pyknometer method with specific gravity bottles giving an accuracy of 1 in 10<5, is described. 12 The use of a bottle with two graduated capillary necks (based on the Sprengel pyknometer, bicapillary pyknometer ), gives an accuracy of 5 in 10. In very accurate work a correction for the weight of the vapour of a volatile liquid in the unfilled neck of the bottle, pyknometer, or dilatometer (see below), should be applied, i" ... 

If the volume of a specific gravity bottle, pyknometer, or dilatometer is found accurately at one temperature by weighing the vessel empty and then full of a standard liquid, such as water or mercury, this volume will alter as the. temperature is changed. Let Fo=real volume of liquid at 0°C.,... 

Arthur H. Thomas Hydrometer for Liquids Lighter than Water Westphal Specific Gravity Balance Pycnometer Specific Gravity Bottle Lypkin Pycnometer... 

Specific Gravity.—The physical constants of fats and oils are often used for purposes of identification. Those most commonly used are, specific gravity, melting point or solidification point, refractive index and viscosity. The specific gravity may be most readily determined, in the case of oils or easily melting fats by means of an immersion hydrometer. It may also be determined more accurately by use of a specific gravity bottle or picnometer. The specific gravity of some oils may be cited as follows ... 

Determination of Specific Gravity.— The determination of the specific gravity, usually in the case of liquids only, is made by means of a pycnometer or specific gravity bottle. The pycnometer is filled with the liquid, at a definite temperature, and weighed. The weight of the pycnometer empty, and the weight of it when filled with water at a definite temperature, must also be known or must be determined. 

Liquids.—The sp. gr. of liquids is determined by the specific cavity balance, by the specific gravity bottle, sometimes called pionometer, or by the spindle or hydrometer. 

Figure 4.2 A A pycnometer (or specific gravity bottle ) is an accurate volumetric flask whose weight change when totally filled with liquid gives the density of that liquid. B A hydrometer measures the buoyant density of the fluid by the level at which it floats...

Other methods of determining density can be used, such as the specific gravity bottle or pyknometer. Flowever, the density-column method is usually far simpler and of greater accuracy for the small samples usually used in polymer research, for which an inaccuracy of 0.1 kg m can be achieved. 

The simplest instrument for measuring liquid density is the hydrometer, a float with a graduated stem. To approach reasonable accuracy, however, it is essential to make the measurement at the particular calibration temperature marked on the hydrometer. Densities may be determined more accurately by the specific gravity bottle method, or with a pyknometer (BS 733, 1983) or Westphal balanee, details of which may be found in most textbooks of practical physics. 

---