Examples volume percent

A stock solution is prepared by weighing out an appropriate portion of a pure solid or by measuring out an appropriate volume of a pure liquid and diluting to a known volume. Exactly how this is done depends on the required concentration units. For example, to prepare a solution with a desired molarity you would weigh out an appropriate mass of the reagent, dissolve it in a portion of solvent, and bring to the desired volume. To prepare a solution where the solute s concentration is given as a volume percent, you would measure out an appropriate volume of solute and add sufficient solvent to obtain the desired total volume. 

Percentages can be used as factors. The percentage of something is the number of parts of that thing per hundred parts total. Whatever unit(s) is used for the item in question is also used for the total. For example, the percent by mass of water in a solution is the number of grams of water per hundred grams of solution or the number of kilograms of water per 100 kg of solution. The percent by volume of alcohol in a mixed drink is the number of milliliters of alcohol in lOOmL of the drink, and so forth. If the words by volume or some other similar words are not stated, assume percent by mass. 

Prepare four to six standard solutions of ethanol in water such that the alcohol content of the wine (as indicated on the wine label) is in the middle. For example, if the wine is 15% ethanol (volume percent assumed), standards of 5,10,20, and 25% are appropriate. Use 25-mL volumetric flasks, and pipet the ethanol accurately. Dilute to the mark with water and then add 1.00 mL of acetone (the internal standard) above the mark. Shake well. 

Important properties of petroleum and its fractions are measured by standardized procedures according to the API or ASTM. A particularly distinctive property is the true boiling point (TBP) curve as a function of the volume percent distilled under standardized conditions. Figure 13.19 is the TBP curve of a whole crude on which are superimposed curves of products that can be taken off sidestreams from a main distillation column, as in Figure 19.21. As samples of the distillate are collected, their densities and other properties of interest also are measured. The figure with Example 13.14 is of such measurements. 

Uniformity of lower limits on a mass basis. Concentrations of vapors and gases usually are reported in volume percent. As molecular weight increases, the lower limit usually decreases. On a mass basis, the lower limits for hydrocarbons are fairly uniform at about 45 mg/L at 0°C and 1 atm. Many alcohols and oxygen-containing compounds have higher values for example, on a mass basis, ethyl alcohol in air has a lower limit of 70 mg/L.27... 

Figure 1 shows an example 30 percent lead inclusions (a = 2mm) in epoxy, Epon 828Z, Here 0 —0 and a is seen to be essentially due to Ops at low frequencies. The volume concentration of inclusions in this example is, however, known to be rather high for Equation (29) to yield exact predictions. It has been pointed out that Equation (31) does not predict the shift in resonance frequency with concentration that is experimentally observed for Pb in epoxy at volume concentrations above 5 percent. Note the steep rise of of and the attenuation edge (predicted by Equation (30) at all concentrations of inclusions), approaching the characteristic (Rayleigh) dependence of Opg below the dipole resonance frequency Equation (26), At ka>l, attenuation is controlled by high frequency resonances above the quadrupole resonance. 

Lowenstam and Weiner (1989, pp. 8-11, table 2.1) clearly show that carbonates dominate in biomineralization. They even occur in plants and fungi. The volume percent of limestone and marbles is well documented from the Precambrian to the present. Whether these rocks are inorganic precipitates or festooned with fossils, many of the living creatures had biomineralized with calcium carbonate, is usually clear. Indeed, some strata are composed entirely of calcium carbonate shells. We present examples of carbonate mineral deposition in cyanobacteria, corals, coccoliths, foraminifera, mollusks, echinoids, and the arthropods. 

The analyses of gases such as air, combustion products, and the like are usually on a dry basis—that is, water vapor is excluded from the analysis. Such an analysis, called an Orsat analysis, is explained in Sec. 2.3. If the gas acts as an ideal gas and its cornponents are each measured by volume, you know (or will learn in Sec. 3.1) that volume percent under ordinary conditions is the same as mole percent. For example, consider the composition of air, which is approximately... 

Volume percent is commonly used to specify the concentration of a solution prepared by diluting a pure liquid compound with another liquid. For example, a 5% aqueous solution of methanol usually describes a solution prepared by diluting 5.0 mL of pure methanol with enough water to give 100 mL. 

Weight/volume percent is often employed to indicate the composition of dilute aqueous solutions of solid reagents. For example, 5% aqueous silver nitrate often refers to a solution prepared by dissolving 5 g of silver nitrate in sufficient water to give 100 mL of solution. 

Naphtha can constitute from 10 to 35 volume percent of crude oil. Despite this difference, considerable similarities were observed in different crude oils if the comparison uses the ratios of each hydrocarbon to the volume percent of K-hexane (Smith, 1968). Table IX gives a very simple example of this by demonstrating the similarity between two different naphthas. 

Water absorption showed a rather complex quantitative pattern for composites of HDPE, wood flour, and talc. Evidently, the higher the plastic content and the talc content, the lower the water absorption. However, in the triple system when talc also replaced plastic, and wood fiber content increased, the relationship with water absorption was not that simple, particularly when weight and volume percents of the ingredients were considered. For example, after 4000 h of water immersion, the composition of 44% HDPE, 27% wood flour, and 27% talc (the balance was a lubricant) absorbed 6% water (w/w). A slight increase of HDPE content to 47%, with a concurrent increase of wood flour to 40% and decrease of talc content to 10% gave 11% of water absorption. A sharp decrease of HDPE content to 25%, with both a concurrent decrease of wood flour (36%) and increase in talc (36%) resulted in 13% of water absorption. Finally, a composition with 28% of HDPE, 54% of wood flour, and 14% of talc absorbed 20% of water [6-8]. 

The ASTM method describes as an example polyisocyanurate (Procedure A) and extruded polystyrene (Procedure B), both samples 3 in. thick, in terms of the average water absorption as volume percent. For polyisocyanurate it is 2.06 0.14% (within-laboratory tests) and 2.1 + 0.5% (between-laboratory tests). For extruded polystyrene it is 0.17 0.04% (within laboratory tests) and 0.17 0.08% (between-laboratory tests). 

Figure 2.40, presented earlier, is an example of concentration of whole yeast cells. Though the concentration of cells at the end of the run was only 10%, the data imply that cells may be concentrated up to the close packed sphere density of 75 volume percent. Indeed, yeast, and E. colt concentrations of 60% and 37% respectively have been harvested. 

A common symbol for volume percent is % (v/v). Commercial rubbing alcohol, for example, is an aqueous solution of isopropyl alcohol (a three-carbon alcohol) that contains 70 volumes of isopropyl alcohol per 100. volumes of solution, and the label indicates this as 70% (v/v). Parts-by-volume concentrations are most often used for liquids and gases. Minor atmospheric components occur in parts per million by volume (ppmv). For example, there are about 0.05 ppmv of the toxic gas carbon monoxide (CO) in clean air, 1000 times as much (about 50 ppmv of CO) in air over urban traffic, and 10,000 times as much (about 500 ppmv of CO) in cigarette smoke. 

By lowering the volume percent of resin and increasing the volume percent of the filler, the composite CTE is reduced. This is best illustrated in Figure 3.17 where an epoxy resin formulated with 15 phr of m-phenylenediamine has a CTE of 50 ppm/°C without filler. The addition of about 60% by weight of alumina, for example, lowered the CTE to about 25 ppm/°C. 

The proof of an alcoholic beverage is twice the volume percent of ethanol 80-proof vodka, for example, contains 40% ethanol by volume 95% ethanol is 190 proof. 

Partially water-miscible organic solvents (PMOSs) may act as either cosolvents or cosolutes, and the research in the past has shown flic complexity of their effects. " It was demonstrated that in order to exert effects on solubility or sorption of HOCs, PMOSs must exist as a component of the solvent mixture in an appreciable amount Munz and Roberts suggested a mole fi action of greater than 0.005 and Rao and coworkers proposed a volume percent of 1% or a concentration above lO mg/L. Cosolvents with relatively high water solubility are likely to demonstrate observable effects on the solubilities of solutes, up to their solubility limits, in a similar manner to cosolvents of complete miscibility with water. A few experimental examples of the effects of PMOSs include 1 -butanol and... 

A standard practice gives the method of calculation of gas chromatographic response factors. The response factor is a constant of proportionality used for conversion of observed chromatographic response of a particular compoimd (e.g., peak area or peak height) to its mass or volume percent in composition. The standard shows how to obtain these response factors based on an example of a mixture of n-paraffins. 

---