Percent-by-Weight Solutions

Percent-by-weight solution—representation in which the concentration of the solute is expressed as a percentage of the total weight of the solution. 

Percent-by-weight solutions are expressed as a percentage of the weight of the total solution. In other words, the weight of the solute (material being dissolved) is taken in relationship to the weight of the entire solution. 

Solubility is given in parts by weight (of the formula weight) per 100 parts by weight of the solvent (i.e., percent by weight) and at room temperature. Another unit frequently used is grams per 100 mF of solvent (mF per 100 mF for liquids and gases). The symbols of the common mineral acids represent aqueous solutions of these acids. 

Balling. Balling is a measure of the sugar concentration in a grain mash, expressed in degrees. It approximates percent by weight of the sugar in solution. 

In which 100 cc could be polymerized. We used a pressure gage, rated from 0 to 140 pounds per square Inch. There were 3 type J thermocouples - one In the center of the solution, one In the reactor wall, and the third near the heater outside the reactor. The experiments were conducted In a high pressure bay and observed on closed circuit television. The Initial polymer concentrations of the test reactants were either 0 or 15 or 30 percent by weight. An electric heater controlled the ambient temperature of the nitrogen - purged reactor, and supplied heat to Initiate the reaction. 

Electrolytic cleaning should be preceded by scrubbing to remove loosely adhering corrosion products. One method of electrol c cleaning that has been found to be useful for many metals and alloys is as follows Solution 5 percent (by weight) H2SO4 Anode carbon or lead Cathode test specimen Cathode current density 20 A/dm (129 A/in )... 

The binder used in Giatt granulation is a six percent (6%) by weight solution of PVA in water. The binder is accurately weighed and slowly paired into the stirred non-heated water. When all the PVA is0added, heat is applied to bring the terrperature of the slurry to 185>. This temperature is maintained for at least 30 minutes, or until all the PVA is in solution. At this point the application of heat is discontinued and the binder is allowed to cool before use. 

Percent weight-in-weight (percent by weight), % w/w number of grams of a constituent (solute) in 100 g of preparation (solution)... 

Percent by weight (Wo wt/wt) concentration based on the number of grams of solute per 100 g of solution. 

Introduction. Degrees Brix is a term used to designate the percent by weight of dissolved sugar in a solution. In citrus juices it is used to indicate the percent of soluble solids contained in the juice. This is one of the more important... 

Another method, not specifically described as an asphaltene separation method, is designed to remove pentane- or heptane-insoluble constituents by membrane filtration (ASTM D-4055). In the method, a sample of oil is mixed with pentane in a volumetric flask, and the oil solution is filtered through a 0.8-p.m membrane filter. The flask, funnel, and filter are washed with pentane to completely transfer any particulate matter onto the filter, after which the filter (with the particulate matter) is dried and weighed to give the pentane-insoluble constituents as a percent by weight of the sample. Particulate matter in the extracts can also be determined by membrane filtration (ASTM D-2276 ASTM D-5452 ASTM D-6217 IP 415). 

Formally, percent by weight to volume is defined as grams of solute per 100 mL of solution. There are two mathematically equivalent statements of this definition ... 

Percent by Weight (% w/w) Percent by weight is commonly reported by chemical analysts. The definition of percent by weight is exactly analogous to the definition of percent weight to volume, except the denominator expresses the quantity of solution in terms of grams, not milliliters. 

For example, what is the percent by weight concentration of glucose in a solution prepared by dissolving 25 g of glucose in 475 g of water As with all solutions problems, we need to be very careful about the definitions. The mass of solute is obviously 25 g, but what about the grams of solution The solution consists of both glucose and water, so the total solution mass is 500 g, not 475 g. So the percent concentration is ... 

To relate percent by weight to percent weight to volume, we again need to employ the density of the solution. For example, what is the percent by weight of a D5W solution The density of D5W is 1.0157 g/mL. Let s see we need to convert 5.0 g per 100 mL into grams per 100 g. That is, we need to convert the denominator from 100 mL into 100 g. Density is the quantitative relationship between mass and volume. So, let s apply the density as a conversion factor to convert the amount of solution from milliliters into grams. You will find this solution is 4.9% (w/w) glucose. 

Aluminum is present in most rocks and is the most abundant element in the earth s crust (eight percent by weight.) However, its isolation is very difficult and expensive to accomplish by purely chemical means, as evidenced by the high E° (-1.66 v) of the A13+/A1 couple. For the same reason, aluminum cannot be isolated by electrolysis of aqueous solutions of its compounds, since the water would be electrolyzed preferentially. And if you have ever tried to melt a rock, you will appreciate the difficulty of electrolyzing a molten aluminum ore Aluminum was in fact considered an exotic and costly metal until 1886, when Charles Hall (U.S.A) and Paul Herault (France) independently developed a practical electrolytic reduction process. 

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