Barium chloride, mole

A solution of 257 g. (1.05 moles) of barium chloride dihydrate in about 500 cc. of hot water is added to the reaction mixture, with vigorous shaking, and the mixture is heated on a steam bath for one-half hour. A heavy precipitate of the barium salt of the amino acid separates at once. After cooling to room temperature, the barium salt is collected on a suction filter, transferred to a beaker, and washed with two 250-cc. portions of hot water (8o°). After drying at ioo°, the barium salt weighs 225-230 g. (80-82 per cent of the theoretical amount). 

A mixture of 132.5 g. (1.05 moles) of sodium sulfite, 99.5 g. (0.5 mole) of bis-4-chlorobutyl ether (Note 1), and 450 ml. of water is placed in a creased 1-1. three-necked flask fitted with an efficient sealed stirrer and a reflux condenser. The third neck of the flask is closed with a stopper, and the mixture is heated and stirred vigorously under reflux until the ether has dissolved (Note 2). At the end of this time, heating is discontinued, and 60 ml. of concentrated c.p. hydrochloric acid is cautiously added to the solution. The mixture is then boiled with stirring until sulfur dioxide is no longer evolved. Solid barium chloride dihydrate (or a 10% aqueous solution of this salt) is added to the hot solution (Note 3) until all sulfate has been precipitated then the barium sulfate is removed by suction filtration through a layer of filter aid. 

Fe2(S04)3 (aq.). Thomsen15 measured the heat of reaction of aqueous barium chloride with aqueous ferric sulfate to be 27.43 per mole of ferric sulfate. His data yield, for Fe2(SO4)3(400), (2/=653.0. See also Berthelot,50 Tamanaeff,1 and Pissarjewsky 2 Data on the heat of dilution of aqueous ferric sulfate were reported by Thomsen,15 Lemoine,1 and Berthelot.5, 26... 

Practice Problem 1 0.30 How many moles of barium ions and how many grams of barium chloride would be required to produce 6.11 g of barium sulfate I... 

Notice in Table 1 that the same about 25 joule rule also applies to the molar heat capacities of solid ionic compounds. One mole barium chloride has three times as many ions as atoms in 1 mol of metal. So, you expect the molar heat capacity for BaCl2 to be C = 3 x 25 J/K mol. The value in Table 1,75.1 J/K mol, is similar to this prediction. 

Formula for a hydrate How can you determine the formula for a hydrate You must find the number of moles of water associated with one mole of the hydrate. Suppose you have a 5.00-g sample of a hydrate of barium chloride. You know that the formula is BaCl2-xH20. You must determine x, the coefficient of H2O in the hydrate formula that indicates the number of moles of water associated with one mole of BaCl2. To find x, you would heat the sample of the hydrate to drive off the water of hydration. After heating, the dried substance, which is anhydrous BaCl2, has a mass of 4.26 g. The mass of the water of hydration is the difference between the mass of the hydrate (5.00 g) and the mass of the anhydrous compound (4.26 g). 

The ratio of moles of H2O to moles of BaCl2 is 2 1, so two moles of water are associated with one mole of barium chloride. The value of the coefficient X is 2 and the formula for the hydrate is BaCl2 2H20. What is the name of the hydrate The CHEMLAB at the end of this chapter will give you experience determining the formula of a hydrate. 

Mercaptoacetic acid 267 This is formed very smoothly, even in aqueous solution, as follows. A solution of chloroacetic acid (100 g) is added gradually to a stirred solution (ca. 15%) of potassium hydrogen sulfide (2 moles) in water (500 ml). The mixture is heated for 15 min on a water-bath,then treated with a concentrated solution of barium chloride, followed by 25% ammonia solution (ca. 1.25 mole). The barium salt is caused to separate by scratching and shaking and is collected and treated with a three-fold amount of 12% hydrochloric acid. The acid liberated is taken up in ether and purified by distillation (b.p. 107-108°/16 mm). 

How many moles of barium chloride are present in tOOg of the hydrate ... 

What is the ratio of moles of barium chloride to moles of water ... 

For those hydrates that don t decompose thermally, the extent of hydration can be determined by weighing the solid sample before and after heating. The mass after heating is for the anhydrous salt, and the difference in the two masses gives the mass of water originally present. Moles of both the anhydrous salt and water can then be calculated, and the mole ratio of water to anhydrous salt can be determined. These ideas are illustrated with a hydrate of barium chloride, BaCl2 xH20. 

The equation shows that three moles of solid (one of hydrated barium hydroxide and two of ammonium chloride) produced eleven moles of product (two of ammonia, eight of water and one of hydrated barium chloride). Also, ten of the moles produced are gas or liquid. 

You are carrying out a laboratory reaction that requires 0.0360 mole of barium chloride. How many grams of the compound do you measure out ... 

Let s take the example of the mixing of 50 ml of a 3 x 10 mol/L barium chloride solution with 100 ml of a 4.5 x 10 mol/L sodium sulfate solution. The problem is to determine the fraction of barium precipitated. Let s call P the number of moles of precipitated barium sulfate per liter of solution. The mass balance relations on Ba +, 504 together with the solubility-product expression provide a system of three equations in three unknowns [Ba +], [804 ], and P ... 

Ci()-Ci2 alkyl 1- to 15-mole ethoxylates ethoxy distribution Merck Silica Gel 60 F-254, 0.25 mm, activated at 120-C for 15 min 80 14 10 ethyl acetate/HOAc/HzO Eosin modified Dragendorff reagent barium chloride/triio-dide solution 9... 

Coco acid mono- and diethano-lamide, oleic acid amide 6-mole ethoxylate, coco acid ethanolamide 5-mole ethoxylate detection in presence of other nonionics Merck Silica Gel GF-254 impregnated with oxalic acid 90 10 CHCla/MeOH Modified Dragendorff reagent barium chloride/triiodide solution 38... 

Note particularly that the numbers of moles of chloride ion from the two solutions are added, but that the moles of sodium ion and the moles of barium ion are not added. 

As part of her Ph.D. research (Radioactive Substances, 1903), Marie Curie measured the atomic mass of radium, a new, radioactive element that she discovered. She knew that radium is in the same family as barium, so the formula of radium chloride is RaCl2- In one experiment, 0.091 92 g of pure RaCl2 was dissolved and treated with excess AgN03 to precipitate 0.088 90 g of AgCl. How many moles of Cl were in the RaCl2 From this measurement, find the atomic mass of Ra. 

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