Presentation on theme: "Water Class #4 OB: continued practice with table G, water math problems, and some vocabulary, then Part 2 of the Water Lab."— Presentation transcript:
Water Class #4 OB: continued practice with table G, water math problems, and some vocabulary, then Part 2 of the Water Lab
Factors affecting solubility in water 1. temperature 2. solubility— like dissolves like, and insoluble exceptions from table F Solutes dissolve into solvents When 2 or more liquids dissolve into each other they are miscible. When they don’t, they’re immiscible.
In these solutions, are they saturated or unsaturated? If unsaturated, how many more grams of solute can fit? TempMass of soluteSoluteSat or Unsat?# grams 30°C60 gHClUn~7 g 60°C100 gKNO 3 Un~5 g 60°C125 gNaNO 3 SatX 90°C10 gNH 3 SatX 20°C30 gKClUn~ 3 g 5°C36 gNaClun~ 2 g Temp Mass of solute Solute Saturated or Unsaturated # grams to saturation 3060 gHCl 60100 gKNO 3 60125 gNaNO 3 9010 gNH 3 2030 gKCl 536 gNaCl
In these solutions, are they saturated or unsaturated? If unsaturated, how many more grams of solute can fit? TempMass of soluteSoluteSat or Unsat?# grams 30°C60 gHClUn~7 g 60°C100 gKNO 3 Un~5 g 60°C125 gNaNO 3 SatX 90°C10 gNH 3 SatX 20°C30 gKClUn~ 3 g 5°C36 gNaClun~ 2 g Temp Mass of solute Solute Saturated or Unsaturated # grams to saturation 3060 gHClunsaturated~ 7 g 60100 gKNO 3 unsaturated~ 5 g 60125 gNaNO 3 saturatedx 9010 gNH 3 saturatedx 2030 gKClunsaturated~ 3 g 536 gNaClunsaturated~ 2 g
Ionic Solid with cations and anions Water molecules “rip” the ions apart, and “juggle” them in a POLAR way.
At left, NONPOLAR molecules (possibly oil) are interspersed with water molecules. This is an UNTRUE version, since like dissolves like only. It shows, for teaching purposes, that the polar water molecules would be less energetically stressed if they were together. At right, is a somewhat more realistic diagram, where the water is attracted together, and the nonpolar molecules are pushed out from the water. The water attracts, and the nonpolar molecules are literally “squeezed out” from the water. If the nonpolar molecule is less dense than water, it floats. If it were to be more dense than water, it would sink.
Your saturated solution of KNO 3 is at 60°C and 100 mL. You cool it down to 20°C. What do you find? ?
Your saturated solution of KNO 3 is at 60°C and 100 mL. You cool it down to 20°C. What do you find? At 60°C 106 g saturates the solution At 20°C - 35 g saturates the solution 71 g precipitates out of solution
What happens when you put 140 g KI into 100 mL water at 10°C?
Only 135 g fits, so five grams falls to the bottom of the beaker. Simulated KI Do not attempt this at home kids, I am a trained professional
Does the precipitate just sit? No, a dynamic equilibrium exists The solid continues to dissolve into the solution, and the precipitate keeps falling out of solution. The rate of solvation equals the rate of precipitation.
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What is an electrolyte? An ionic compound that will ionize in water, creating a soution that will conduct electricity, or, a solution with ions that will conduct electricity. NaCl solid would be an electrolyte because it would conduct if put in water. Salty water is an electrolyte because it would conduct electrity.
Is NaCl (S) an electrolyte? Is NaCl (L) an electrolyte? By definition, both are. Solid salt would be because IF you put it into water it would then conduct electricity. Liquid sodium chloride (crazy hot – melted!) would also have loose ions, so it too would be an electrolyte. Aqueous sodium chloride is an electrolyte too. Sugar water is NOT an electrolyte. It dissolves, but not into ions.
Ionization into water by ionic compounds is called dissociation Here, sodium hydroxide will dissociate into water NaOH (S) Na +1 (AQ) + OH -1 (AQ) HCl (G) H +1 (AQ) + Cl -1 (AQ) C 6 H 12 O 6(S) C 6 H 12 O 6(AQ) NO IONS form, it just dissolves because glucose is polar water