Water molar mass

E 72 grams of water (molar mass of 18) is 4 moles of water. For every 2 moles... 

High purity water (molar mass 18.015 g/mol) is a clear, odourless and tasteless, colourless liquid, which in thick layers appears blue. Some of the physical properties are listed in Table 2. 

Convection current Conduction current Total current Maximum a.c. current Inner Helmholtz plane Membrane partition coefficient Water molar mass... 

Dimefoylhydrazine, foe fuel used in foe Apollo lunar descent module, has a molar mass of 60.10 g/mol. It is made up of carbon, hydrogen, and nitrogen atoms. The combustion of 2.859 g of the fuel in excess oxygen yields 4.190 g of carbon dioxide and 3.428 g of water. What are foe simplest and molecular formulas for dimefoylhydrazine ... 

NaOH for complete neutralization. What is the molarity of the H2X solution (c) Beaker C contains 0.124 g of H2X and 25.00 mL of water. To reach the equivalence point, 22.04 mL of NaOH are required. What is the molar mass of H2X ... 

Not all organic compounds that contain —OH groups are soluble in water (Table 10.1). As molar mass increases, the polar —OH group represents an increasingly smaller portion of the molecule. At the same time, the nonpolar hydrocarbon portion becomes larger. As a result, solubility decreases with increasing molar mass. Butanol, CH3CH2CH2CH2 OH, is... 

In carrying out a molar mass determination by freezing point depression, we must choose a solvent in which the solute is readily soluble. Usually, several such solvents are available. Of these, we tend to pick one that has the largest kf. This makes ATf large and thus reduces the percent error in the freezing point measurement From this point of view, cyclohexane or other organic solvents are better choices than water, because their kf values are larger. 

Insulin is a hormone responsible for the regulation of glucose levels in the blood. An aqueous solution of insulin has an osmotic pressure of 2.5 mm Hg at 25°C. It is prepared by dissolving 0.100 g of insulin in enough water to make 125 mL of solution. What is the molar mass of insulin ... 

Lysozyme, extracted from egg whites, is an enzyme that cleaves bacterial cell walls. A 20.0-mg sample of this enzyme is dissolved in enough water to make 225 mL of solution. At 23°C the solution has an osmotic pressure of 0.118 mm Hg. Estimate the molar mass oflysozyme. 

A biochemist isolates a new protein and determines its molar mass by osmotic pressure measurements. A 50.0-mL solution is prepared by dissolving 225 mg of the protein in water. The solution has an osmotic pressure of 4.18 mm Hg at 25°C. What is the molar mass of the new protein ... 

The water-soluble nonelectrolyte X has a molar mass of 410 g/mol A 0.100-g mixture containing this substance and sugar (MM = 342 g/mol) is added to 1.00 g of water to give a solution whose freezing point is —0.500°C. Estimate the mass percent of X in the mixture. 

The reaction of amines with Fl+ ions has an interesting practical application. Amines of high molar mass, frequently used as drugs, have very low water solubilities. They can be converted to a water-soluble form by treatment with strong acid. For example. 

You are asked to determine whether an unknown white solid is acidic or basic. You also need to say whether the add or base is weak or strong. You are given the molar mass of the solid and told that it is soluble in water. Describe an experiment that you can perform to obtain the desired characteristics of die white solid. 

Table 22.3 compares two physical properties, boiling point and water solubility, of alcohols, ethers, and alkanes of similar molar masses. Notice that—... 

From the preceding discussion, it is easily understood that direct polyesterifications between dicarboxylic acids and aliphatic diols (Scheme 2.8, R3 = H) and polymerizations involving aliphatic or aromatic esters, acids, and alcohols (Scheme 2.8, R3 = alkyl group, and Scheme 2.9, R3 = H) are rather slow at room temperature. These reactions must be carried out in the melt at high temperature in the presence of catalysts, usually metal salts, metal oxides, or metal alkoxides. Vacuum is generally applied during the last steps of the reaction in order to eliminate the last traces of reaction by-product (water or low-molar-mass alcohol, diol, or carboxylic acid such as acetic acid) and to shift the reaction toward the... 

Although low-molar-mass aliphatic polyesters and unsaturated polyesters can be synthesized without added catalyst (see Sections 2.4.1.1.1 and 2.4.2.1), the presence of a catalyst is generally required for the preparation of high-molar-mass polyesters. Strong acids are very efficient polyesterification catalysts but also catalyze a number of side reactions at elevated temperature (>160°C), leading to polymers of inferior quality. Acid catalysts are, therefore, not much used. An exception is the bulk synthesis of hyperbranched polyesters reported in Section 2.4.5.1, which is carried out at moderate temperature (140°C) under vacuum in the presence of p-toluene sulfonic acid catalyst. The use of strongly acidic oil-soluble catalysts has also been reported for the low-temperature synthesis of polyester oligomers in water-in-oil emulsions.216... 

Suppose we dissolved LO.O g of cane sugar in enough water to make 200. mL of solution, which we might do (with less precision) if we were making a glass of lemonade. Cane sugar is sucrose (C H On), which has a molar mass of 342 g-mol" 1. What is the molarity of sucrose molecules in the solution ... 

J.10 (a) White phosphorus, which has the formula P4, burns in air to form compound A, in which the mass percentage of phosphorus is 43.64%, with the remainder oxygen. The mass spectrum of A yields a molar mass of 283.9 g-mol. Write the molecular formula of compound A. (b) Compound A reacts with water to form compound B, which turns litmus red and has a mass percentage composition of 3.087% 11 and 31.60%... 

For example, in Section L.l we saw that 0.50 mol H20 can be produced from 0.25 mol 02. If we want to know the mass of water that can be produced, the additional step is to use the molar mass of water to convert this amount to grams by using m = nM ... 

L.18 A tablet of vitamin C was analyzed to determine whether it did in fact contain, as the manufacturer claimed, 1.0 g of the vitamin. One tablet was dissolved in water to form 100.00 mL of solution, and 10.0-mL of that solution was titrated with iodine (as potassium triiodide). It required 10.1 mL of 0.0521 M I3-(aq) to reach the stoichiometric point in the titration. Given that 1 mol L,- reacts with 1 mol vitamin C in the reaction, is the manufacturer s claim correct The molar mass of vitamin C is 176 g-mol-1. 

M.9 The stimulant in coffee and tea is caffeine, a substance of molar mass 194 g-mol When 0.376 g of caffeine was burned, 0.682 g of carbon dioxide, 0.174 g of water, and 0.1 10 g of nitrogen were formed. Determine the empirical and molecular formulas of caffeine, and write the equation for its combustion. 

M.10 Nicotine, the stimulant in tobacco, causes a very complex set of physiological effects in the body. It is known to have a molar mass of 162 g-mol. When a sample of mass 0.385 g was burned, 1.072 g of carbon dioxide, 0.307 g of water, and 0.068 g of nitrogen were produced. What are the empirical and molecular formulas of nicotine Write the equation for its combustion. 

The average molar mass of molecules in the air, allowing for their different abundances, is 28.97 g-mol. The percentage of water vapor in ordinary air varies with the humidity. 

FIGURE 5.8 The boiling points of most of the molecular hydrides of the p-block elements show a smooth increase with molar mass in each group. However, three compounds—ammonia, water, and hydrogen fluoride are strikingly out of line. 

Osmosis is the flow of solvent through a semipermeable membrane into a solution the osmotic pressure is proportional to the molar concentration of the solute. Osmometry is used to determine the molar masses of compounds with large molecules, such as polymers reverse osmosis is used in water purification. 

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