Concept explainers
(a)
Interpretation:
Equivalence of the magnitude of molality and the molarity in a dilute aqueous solution should be demonstrated.
Concept introduction:
The molarity, molality and density of a solution can be calculated as follows:
(b)
Interpretation:
In a dilute solution, proportionality of the solute mole fraction to the molality should be demonstrated.
Concept introduction:
In a dilute solution, solvent concentration is larger than the solute concentration.
(c)
Interpretation:
In a dilute aqueous solution, proportionality of the solute mole fraction to the molarity should be demonstrated.
Concept introduction:
In an aqueous solution, solvent is water. A dilute aqueous solution, water concentration is larger than the solute concentration.
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EP GENERAL CHEMISTRY-MOD.MASTERINGCHEM.
- A solution is made by dissolving 0.542 mol0.542 mol of nonelectrolyte solute in 901 g901 g of benzene. Calculate the freezing point, ?f,Tf, and boiling point, ?b,Tb, of the solution. Constants can be found in the table of colligative constants.arrow_forwardColligative properties, such as boiling point elevation, depend on the number of dissolved particles in solution. For nonelectrolytes, no dissociation occurs, and so you can use the number of moles of solute to calculate both molality and molarity. In contrast, electrolytes dissociate, and therefore the molality and molarity must be calculated based on the number of moles of dissociated particles or ions. There are two ions per formula unit of NaCl. Therefore, we would expect the freezing-point depression AT of a NaCl solution to be twice that of a sugar solution of the same concentration. However, it has been experimentally determined that in the typical unsaturated solution AT for the salt solution is only 1.9 times that of the sugar solution. This indicates that not all ion pairs in the NaCl solution are dissociated. The number 1.9 is called the van't Hoff factor (symbolized by i) and can be thought of as the number of dissociated particles per NaCl formula unit. This factor changes…arrow_forwardTo 180g of 8% sodium chloride solution was added 20g of NaCl. The mass fraction of sodium chloride in the resulting solution is?arrow_forward
- A student determines the molar mass of acetone, , She found that the equilibrium temperature of a mixture of ice and water was 1.0C on her thermometer. When she added 11.1g of her sample to the mixture, the temperature, after through stirring, fell to -3.0C. She then poured off the solution through a screen into a beaker. The mass of the solution was 90.4g. a. what was the freezing point depression? b. what was the molarity of the acetone? c. how much aceton was in the decanted solution? d. how much water was in the decanted solution? e. how much acetone would there bein a solution containing 1kg of water and acetone at the same concentration as she has in herexperiment? f. what did she find to be the molar mass of aceton, assumingshe made the calculation properly?arrow_forwardThe presence of the radioactive gas radon (Rn) in well waterpresents a possible health hazard in parts of the UnitedStates. (a) Assuming that the solubility of radon in waterwith 1 atm pressure of the gas over the water at 30 °C is7.27 * 10-3 M, what is the Henry’s law constant for radon (c) The free-base form of cocaine has a solubility of 1.00 g in6.70 mL ethanol (CH3CH2OH). Calculate the molarityof a saturated solution of the free-base form of cocaine inethanol.(d) The hydrochloride form of cocaine has a solubility of1.00 g in 0.400 mL water. Calculate the molarity of a saturatedsolution of the hydrochloride form of cocaine inwater.(e) How many mL of a concentrated 18.0 M HCl aqueoussolution would it take to convert 1.00 kilograms(a “kilo”) of the free-base form of cocaine into its hydrochlorideform?arrow_forwardWhat is the molality of HCl in an aqueous solution in which the mole fraction of HCl is 0.220arrow_forward
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- The Henry’s law constant for CO2 in water at 25 °C is3.1x 10-2 M atm-1. (a) What is the solubility of CO2 inwater at this temperature if the solution is in contact withair at normal atmospheric pressure? (b) Assume that all ofthis CO2 is in the form of H2CO3 produced by the reactionbetween CO2 and H2O:CO2(aq) + H2O(l)------>H2CO3(aq)What is the pH of this solution?arrow_forwardA solution contains only sucrose and water. If the mole fraction of sucrose is 0.0558, determine the molality of this sucrose solution.arrow_forwardThe molar mass of liquid A = 85.0 g / mole, that of B = 112.0 g / mole. At 100 C, a solution of mass percentage in A equal to 30.0%, considered ideal, has a vapor pressureof equilibrium equal to 110 kPa. The vapor in equilibrium with this solution has a mole fraction of A equal to 0.450.(a) Determine the mass of A which must be added to 100 g of B to obtain a solution whosenormal boiling point is 100 C. Please give the Answerarrow_forward
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