CHEMISTRY GLOSSARY

absolute volume    →   apsolutni volumen

Absolute volume is the total volume of the particles in a granular material, including both permeable and impermeable voids but excluding spaces between particles.

critical volume    →   kritični volumen

Critical volume is the volume of a fixed mass of a fluid at critical temperature and pressure.

molar volume    →   molarni volumen

Molar volume is the volume occupied by substance per unit amount of substance. The volume of the gas at 0 °C and 101 325 Pa is 22.4 dm³mol^-1.

volume    →   volumen

Volume is a space taken by a certain mass of some matter. SI unit for volume is a cubic meter (m³). Changes of temperature or pressure can change volume.

volume ratio    →   volumenski omjer

Volume ratio is equal to volume (V_A) of one component and volume (V_B) of other component’s proportion.

volumetry    →   volumetrija

Volumetry consists of adding an equivalent amount of a reagent of exactly known concentration to the analyte. From stechiometrical proportion and added volume of reagent the quantity of matter in question can be calculated.

volume concentration    →   volumenska koncentracija

Volume concentration (σ) is equal to volume (V_A) of solute and volume (V) of solution proportion. Volume concentration differs from volume fraction because the sum of solution components volume is almost always different than the solution volume.

volume fraction    →   volumenski udio

Volume fraction (φ_A) is defined as

where V_A is the volume of the specified component and the V_i are the volumes of all the components of a mixture prior to mixing.

volumetric flask    →   odmjerna tikvica

Volumetric flasks are bottles made of glass, in a pear like in shape with long thin necks and flat bottoms. All come with a ground glass stopper for a tight seal. Volume marking is cut in glass with fluoride acid around the neck, so that parallax should be avoided (flask is put in front of the eyes so that one can see only a straight horizontal line). A volumetric flask is calibrated to contain (TC or In) the indicated volume of water at 20 °C when the bottom of the meniscus is adjusted to just rest on the center of the line marked on the neck of the flask. They are used for preparing the exactly known volume of sample solution and standard solutions of reagents. On each flask with volume designation a temperature on which the flask has been calibrated is designated.

volumetric pipette    →   prijenosna pipeta

Volumetric pipettes (transfer or belly pipette) are used in volumetric analysis, when there is a need for taking exact smaller volume of a sample solution or reagent. The upper tube of volumetric pipette has a ringlike marking (mark) which marks its calibrated volume. Pipettes calibrated to deliver (TD or Ex) the indicated volume. By sucking in (with mouth, propipette or a water pump) the liquid is pulled in a little bit above the mark and the opening of the pipet is closed with a forefingertip. Outer wall of pipet is wiped and, with a slight forefinger loosening, the liquid is released until it reaches the mark. Mark must figure as a tangent on a lower edge of the liquid meniscus. A pipette is emptied out by lifting the forefinger off and letting the liquid flow out of the pipette freely. After another 15 s and the tip of the pipette is pulled onto the inner wall of the vessel. It is absolutely forbidden to blow out the contents of the pipette.