A. % Concentration 1 GIVEN: FIND: APPROACH: 52.3 g of NaCl completed dissolved in 215.6 g solvent % (m/m) NaCl % = (amount of solute / amount of solution) x 100%

Solutions Introduced directly into the bloodstream have to be isotonic with blood; that is, they must have the same osmotic pressure as blood. An aqueous NaCl solution has to be 0.90% by mass to be isotonic with blood. What is the molarity of the sodium ions in solution? Take the density of the solution to be 1.00 g/mL.

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 25C. 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?

The Henry's law constant for the solubility of argon gas in water is 1.0103M/atm at 30C. (a) Express the constant in M/mm Hg. (b) If the partial pressure of argon gas at 30C is 693 mm Hg, what is the concentration (in M) of the dissolved argon gas at 30C? (c) How many grams of argon gas can be dissolved in 29 L of water at 693 mm Hg and 30C? (Ignore the partial pressure of water.)

Cooking A cook prepares a solution for boiling by adding12.5 g of NaCl to a pot holding 0.750 L of water. Atwhat temperature should the solution in the pot boil?Use Table 14.5 for needed data.

Sodium chloride (NaCl) is commonly used to melt ice on roads during the winter. Calcium chloride (CaCl2) is sometimes used for this purpose too. Let us compare the effectiveness of equal masses of these two compounds in lowering the freezing point of water, by calculating the freezing point depression of solutions containing 200. g of each salt in 1.00 kg of water. (An advantage of CaCl2 is that it acts more quickly because it is hygroscopic, that is. it absorbs moisture from the air to give a solution and begin the process. A disadvantage is that this compound is more costly.)

Caffeine is made up of 49.5% C, 5.2% H, 16.5% O, and 28.9% N. A solution made up of 8.25 g of caffeine and 100.0 mL of benzene (d=0.877g/mL) freezes at 3.03C. Pure benzene (k f =5.10C/m) freezes at 5.500C. What are the simplest and molecular formulas for caffeine?

Many solutions are found in the home. Some are listed below, with the composition as printed on the label. When no percentage is indicated, components are usually given in order of decreasing amount. When water is present, it is often not mentioned on the label or it is included in the inert ingredients. Identify the solvent and solutes of the following solutions: a.Antiseptic mouthwash: alcohol 25, thymol, eucalyptol, methyl salicylate, menthol, benzoic acid, boric acid b.Paregoric: alcohol 45, opium 0.4 c.Baby oil: mineral oil, lanolin there happens to be no water in this solution-why? d.Distilled vinegar: acetic acid 5

Solutions of hydrogen in palladium may be formed by exposing Pd metal to H2 gas. The concentration of hydrogen in the palladium depends on the pressure of H2 gas applied, but in a more complex fashion than can be described by Henry's law. Under certain conditions, 0.94 g of hydrogen gas is dissolved in 215 g of palladium metal (solution density = 10.8 g cm3). (a) Determine the molarity of this solution. (b) Determine the molality of this solution. (c) Determine the percent by mass of hydrogen atoms in this solution.

You have read that adding a solute to a solvent can both increase the boiling point and decrease the freezing point. A friend of yours explains it to you like this: The solute and solvent can be like salt in water. The salt gets in the way of freezing in that it blocks the water molecules from joining together. The salt acts like a strong bond holding the water molecules together so that it is harder to boil. What do you say to your friend?