Solutions percent composition

An alloy made up of tin and copper is prepared by simultaneously electroplating the two metals from a solution containing Sn(N03)2 and Cu(N03)2. If 20.0% of the total current is used to plate tin, while 80.0% is used to plate copper, what is the percent composition of tire alloy ... 

In most commercial processes, borax is obtained from lake brines, tincal and colemanite. The primary salt constituents of brine are sodium chloride, sodium sulfate, sodium carbonate and potassium chloride. The percent composition of borax as Na2B40 in brine is generally in the range 1.5 to 1.6%. Borax is separated from these salts by various physical and chemical processes. The brine solution (mixed with mother liquor) is subject to evaporation and crystahzation for the continuous removal of NaCl, Na2C03 and Na2S04, respectively. The hot liquor consists of concentrated solution of potassium salts and borate components of the brine. The insoluble solid particles are filtered out and the liquor is cooled rapidly in continuous vacuum crystallizers under controlled conditions of temperatures and concentrations to crystallize KCl. Cystallization of borax along with KCl from the concentrated liquor must not occur at this stage. KCl is separated from the hquor by filtration. Bicarbonate then is added to the liquor to prevent any formation of sodium... 

Elemental composition (for anhydrous NiCb) Ni 45.30%, Cl 54.70% Percent composition of NiCl2 6H20 Ni 24.69%, Cl 29.83%, H2O 45.48%. Nickel may be analyzed in an aqueous solution of salt by various instrumental techniques (See Nickel). Chloride ion in the aqueous solution may be determined by titration with silver nitrate using potassium chromate indicator or preferably by ion-chromatography. The solutions must be appropriately diluted for all analyses. 

What is the percent composition Na2S04 (density 1.03) if it contains 0.001 g salt per mL of solution ... 

These results indicate that the 7 percent composition of t-Cs in D and the 3 percent composition of t-C4 in B obtained in the original column can also be obtained with the smaller column. These results disagree somewhat with the answers obtained from a rigorous computer solution, as shown in the following comparison. However, given the approximations that went into the FUG method, the agreement is good. 

Consider an aqueous solution containing sodium chloride that has a density of 1.01 g/mL. Assume that the solution behaves ideally. The freezing point of this solution at 1.00 atm is — 1.28°C. Calculate the percent composition of this... 

You take 20.0 g of a sucrose (Ci2H22On) and NaCl mixture and dissolve it in 1.0 L of water. The freezing point of this solution is found to be —0.426°C. Assuming ideal behavior, calculate the mass percent composition of the original mixture, and the mole fraction of sucrose in the original mixture. 

Scientists use different concentration units that describe the composition of a solution. Percent concentration, molarity, molality, normality, and parts per million (ppm) are some of the concentration units. 

One common way of describing a solution s composition is mass percent, otherwise known as weight percent or percent by weight. Mass percent expresses the mass of solute present in a given mass of solution. To calculate mass percent, the mass of solute is divided by the mass of the solution and multiplied by 100. 

Chemists frequently express concentrations in terms of percent (parts per hundred). Unfortunately, this practice can be a source of ambiguity because percent composition of a solution can be expressed in several ways. Three common methods are... 

These principles are illustrated with reference to the hypothetical alloy system shown in Fig. 12-3. This system contains two substitutional terminal solid solutions a and p, both assumed to be face-centered cubic, and an intermediate phase y, which is body-centered cubic. The solubility of either A or B in y is assumed to be negligibly small the lattice parameter of y is therefore constant in all alloys in which this phase appears. On the other hand, the parameters of a and P vary with composition in the manner shown by the lower part of Fig. 12-3. Since the B atom is assumed to be larger than the A atom, the addition of B expands the A lattice, and the parameter of a increases from a for pure A to 03 for a solution of composition x, which represents the limit of solubility of B in A at room temperature. In two-phase (a -t- y) alloys containing more than x percent B, the parameter of a remains constant at its saturated value a. Similarly, the addition of A to B causes the parameter of P to decrease from 02 to 04 at the solubility limit, and then remain constant in the two-phase (y -1- P) field. 

Solution The first step is to determine the empirical formula from the percent composition data. 

A solution of 4.3 I g of solute in 149 g of cyclohexane freezes at 2.7°C. The solute contains 40.0% carbon, 6.67% hydrogen, and 53.3% oxygen, (o) What can we calculate from the change in freezing point and tabulated data (b) What can we calculate from the masses and the answer to part (a) (c) What can we calculate from the percent composition data (d) What can we calculate from the answers to parts (b) and (c) ... 

Actually, in most cases, a correction is not necessary because the error resulting from the buoyancy will cancel out in percent composition calculations. The same error will occur in the numerator (as the concentration of a standard solution or weight of a gravimetric precipitate) and in the denominator (as the weight of the sample). Of course, all weighings must be made with the materials in the same type of container (same density) to keep the error constant. 

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