General Chemistry
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A solution of ascorbic acid (C6H8O6) was prepared in 180.0 g of water. The solution was found to have a boiling point of 101.25 °C. Find the molality of the solution. The value of Kb for water is 0.52 °C•kg/mol.
When 36.3 g of ibuprofen (MW = 206.3 g/mol) is dissolved in 235 g ethanol, the resulting solution boils at 0.90 °C higher than pure ethanol. Calculate the value of Kb (boiling point constant) for ethanol.
The phase diagram given below shows the relationship between vapor pressure and temperature for pure ethanol and for a solution of ethanol containing a nonvolatile solute.
Use this diagram to determine the approximate molality of the solute in solution. (Kb for ethanol is 1.2 °C/m)
For a 0.150 M solution of sodium ascorbate, NaHC6H6O6, what is its boiling point if it has a density of 1.05 g/mL? (Ka1 = 8.0×10–5, Ka2 = 1.6×10–12)
The boiling point of a solution composed of 1.21 g caffeine in 60.0 g ethanol is elevated by 0.127 ºC. Determine the molar mass of caffeine.
A solution containing 0.200 mol of a nonvolatile nondissociating solute in 400 g phenol boils at 183.47 ºC. If pure phenol boils at 181.7 ºC, calculate the ebullioscopic constant Kb for phenol.
Magnesium chloride is dissolved in 150.0 mL of water to make a 12.5% MgCl2 solution by mass. The solution has a density of 1.105 g/cm3. Calculate the mass of solute or solvent that must be added in order to make the boiling point of the solution 108.2°C. The van't Hoff factor of MgCl2 is 2.70.
The boiling point of a 2.4 m solution of an ionic compound MX3 is 103.9°C. What is the van't Hoff factor (i) for MX3?
38.2 g Na2SO4 (molar mass = 142.04 g/mol) is dissolved in 1470 g of water (Kb = 0.512 oC/m). What is the boiling point of the solution?
The boiling point and boiling point elevation constant of chloroform are 61.2 °C and 3.63 °C/m, respectively. What is the boiling point of a solution made of 89.3 g of benzoic acid (molar mass = 122.12 g/mol) is dissolved in 853 mL of chloroform (1.49 g/mL) ?