Please help me!! I need to know this ASAP! If you can answer any parts please tell me the parts you know. I really need someone to walk me through each step if possible...like show work and all. Thanks so much.
A. What is the freezing point and boiling point of an aqueous solution of KCl that contains 105 grams of KCl in 625 mL of water?
B. An aqueous solution of an unknown solute is made by adding 43.8 grams of the solute to water. This solution lowers the freezing point of the water by 0.935 degrees C. What is the mass of the unknown solute?
C. A 778 gram sample of aqueous solution contains 133.0 grams of RbBr. The vapor pressure of pure water at 20 degrees C is 17.5 mm Hg. What is the vapor pressure of the water in the RbBr solution?
2007-03-19 13:31:11 · 2 answers · asked by XoswimXo 1 in Science & Mathematics ➔ Chemistry
A. find molality (moles solute over kg solvent) of KCl (make sure you multiply by 2 since KCl disassociates, otherwise just make sure u get the units right)
freezing point is lowered by molality * Kf of water
boiling point is raised by molality * Kb of water
B. use freezing point is lowered by molality * Kf of water
2007-03-19 13:53:27 · answer #1 · answered by Jeffrey W 3 · 0⤊ 0⤋
a)Hydrogen bonding is present day in water, to a lesser volume in ammonia, and under no circumstances in any respect in methane. even as hydrogen bonding is present day, more advantageous ability could be invested to conquer the intermolecular forces. b)At 25C and a million atm. chlorine is a gasoline, bromine a liquid, and iodine a strong by way of Van der Waal's rigidity (London dispersion rigidity) which will strengthen with mass. Chlorine, the lighest of the three, is in a gaseous area because a lot less ability replaced into required to conquer the Van der Waal's rigidity. c)calcium oxide melts at a a lot more advantageous temperature than does potassium chloride because calcium oxide has a a lot more advantageous lattice ability because of the extreme prices of Ca and O (2and -2 respectively) vs. the prices of KCL (a million and -a million on the ions respectively). d) ethanol is a liquid somewhat than a gasoline because unlike propane, ethanol contains an O-H team giving it hydrogen bonding and is the reason the better boiling aspect of ethanol.
2016-11-26 23:30:50 · answer #2 · answered by ? 4 · 0⤊ 0⤋