Concentration mass percent

Solution concentrations are often presented as a percent concentration (mass percent). Ten percent NaOH solution is used to break down wood fibers often used to make paper. For this example, how many grams of solute are added to how many grams of solvent to prepare 100 g of 10% NaOH solution ... 

Concentration Mass Percent Volume Percent Mass/Volume Molarity... 

Note 9— In addition to the calibration standards identified in 6.4, single-element or multielement calibration standards may also be prepared fix>m materials similar to the samples being analyzed, provided the calibration standards to be used have previously been characterized by independent, primary (for example, gravimetric or volumetric), and a ytic techniques to establish the elemental concentration mass percent levels. 

Figure 1 Thermal oxidative breakdown of polyethylene (temperature 200°C P02 = 350 Tor stabilizer concentration 0.5 mass percent). 1-without stabilizer 2-CaO-6 3-polydii-minodiphenylmethane disulfide 4-polydiiminodiphenylsul-fon disulfide 5-polyparaoxydiphenylamine disulfide 6-po-lydimethylaniline disulfide 7-polyaniline disulfide 8-polydiiminodiphenyloxide disulfide 9-polythiosemicarbaz-ide disulfide 10-polyamine disulfide 11-polycarbamide disulfide 12-poly thiocarbamide disulfide 13-polyethylenedi-amine disulfide.

It is frequently necessary to convert from one concentration unit to another This problem arises, for example, in making up solutions of hydrochloric acid. Typically, the analysis or assay that appears on the label (Figure 10.2, p. 263) does not give the molarity or molality of the add. Instead, it lists the mass percent of solute and the density of the solution. 

The label on a bottle of concentrated hydrochloric acid. The label gives the mass percent of HCI in the solution (known as the assay] and the density (or specific gravity) of the solution. The molality, molarity, and mole fraction of HCI in the solution can be calculated from this information. 

Fig. 61. Isotherms (800°C) of specific volume versus TaFs concentration in mass percent for the molten systems KF - KfTaFj (1) and KCl - KfFaFj (after Agulyansky et al. [324]).

Recap 50. mL samples of known concentration of[Ni(NH3)J2+ were made up by using NiS04 6 H20. The concentrations were then plotted versus their absorbance. The unknown solution s absorbance was then extrapolated from this graph and used in the calculation for the mass percent ofNi2+. 

Percent solution is another common way to express concentration. The precise units of percent solution typically depend on the phase of each component. For solids dissolved in liquids, mass percent is usually used ... 

This kind of measurement is sometimes called a mass-mass percent solution because one mass is divided by another. Very dilute concentrations (as in the concentration of a contaminant in drinking water) are sometimes expressed as a special mass percent called parts per million (ppm) or parts per billion (ppb). In these metrics, the mass of the solute is divided by the total mass of the solution, and the resulting fraction is multiplied by 10 (ppm) or by 10 (ppb). 

Clearly, paying attention to units is important when working with concentration. Only by observing which units are attached to a measurement can you determine whether you re working with molarity, with mass percent, or with a mass-mass, mass-volume, or volume-volume percent solution. 

The NTO/TNT formulation is characterized by a lower vulnerability than RDX/ TNT and Composition B. NTO is also used to produce pressed PBXs with thermoplastic binders and cast PBXs with thermosetting binders for IMs. NTO is an explosive with calculated performance near that of RDX but with insensitivity approaching that of TATB. Possible use of NTO is as an alternative to RDX in formulations where a lower sensitivity is desired or as an alternative to TATB where better performance is required without a large increase in sensitivity [123, 152, 153, 215]. The formulations based on NTO/binder (FPC-461, Viton-A, Kel-F800, Estane-5702 and Kraton G) in 95/5 (mass percent concentrations) have also been tested for compatibility and none of the NTO/binder formulations showed evidence of incompatibility. 

Among the congeners investigated was 2,2 ,5,5 -tetrachlorobiphenyl (TeCIBP), which was determined to be present in the Aroclor 1242 mixture at about 3.2 mass percent (i.e., mass fraction miAroclor = 0.032 g, -g jor). The measured aqueous concentrations for this compound were 1.11 pg L 1 (case a) and 0.10 pg-L"1 (case b), respectively. Are these concentrations reasonable What aqueous TeCIBP concentrations would you have predicted from the above information, when assuming that Raoult s law is valid in both cases ... 

In daily life, it s often sufficient to describe a solution as either dilute or concentrated. In scientific work, though, it s usually necessary to know the exact concentration of a solution—that is, to know the exact amount of solute dissolved in a given amount of solvent. There are many ways of expressing concentration, each of which has its own advantages and disadvantages. We ll look briefly at four of the most common methods molarity, mole fraction, mass percent, and molality. 

Closely related to mass percent, and particularly useful for very dilute solutions, are the concentration units parts per million (ppm) and parts per billion (ppb) ... 

PROBLEM 11.3 What is the mass percent concentration of a saline solution prepared by dissolving 1.00 mol of NaCl in 1.00 L of water ... 

The concentration of a solution can be expressed in many ways, including molarity (moles of solute per liter of solution), mole fraction (moles of solute per mole of solution), mass percent (mass of solute per mass of solution times 100%), and molality (moles of solute per kilogram of solvent). When equilibrium is reached and no further solute dissolves in a given amount of solvent, a solution is said to be saturated. The concentration at this point represents the... 

What is the mass percent concentration of the following solutions ... 

The concentration of a solution can be expressed in mass percent, as described below. 

In chemistry, solutions are prepared so that a specific concentration of particles, the solute, is added to a specific volume of solvent. When a uniform mixture of solute and solvent results, a solution is formed. The concentration of a solution is expressed as the ratio of solute to solution, solution being solute plus solvent. In the next demonstration, we examine a change in value through dilution using mass percent as a means of expressing concentration of the solution. In mass percent, the ratio of grams of solute to grams of solution, multiplied by 100, is used to calculate the mass percent of the solution. 

Students will define solution and explain how to express the concentration of a solution using mass percent. 

Mass percent is the concentration of a solution in grams of solute per grams of solution. The mass percent would be 10%. The calculation is as follows 20.0 g of solute divided by 200.0 g of solution /100 = 10%. 

Given the solution composition in mass percent, it is easy to compute the mole fractions of solute and solvent and the molal concentration of solute. 

Active" ZDDP. Differential Infrared Spectroscopy (DIR) was used to determine the concentration of ZDDP in the used oil samples by measuring the absorbance of the P-O-C band at 1,000 cm 1. The ZDDP concentrations of the used oil samples were generally less than 0.05 mass percent (as zinc), which is substantially less than the nominal 0.12 mass percent in the fresh oils. There was no correlation between camshaft and lifter valve wear and amount of ZDDP remaining in the used oil. This result supports other observations that the decomposition of ZDDP results in other compounds which may also exhibit some antiwear properties. 

Fig. 3.18. Free-charge-carrier concentration (a,b) and mobility parameters (c,d) of Ga-doped ZnO thin films on sapphire vs. oxygen pressure during PLD-growth [43]. Triangles and circles correspond to the results determined by IRSE and Hail-effect measurements, respectively. Panels (a,c) and (b,d) contain the results of the films grown with 0.1 and 0.5 mass percent Ga2C>3 powder within the PLD target, respectively. Up- and down-triangles in panels (c) and (d) represent the anisotropic optical mobility parameter /inpt and respectively...

O Examine the photographs below. When concentrated sulfuric acid is added to sucrose, C12H22O11, a column of pure carbon is formed, as well as some water vapour and other gases. How would you find the mass percent of carbon in sucrose using this reaction You may assume that all the carbon in the sucrose is converted to carbon. Design an experiment to determine the mass percent of carbon in sucrose, based on this reaction. Do not try to perform this experiment. What difficulties might you encounter ... 

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