Solubility- the max amt of a subst that will dissolve in a certain quant of water, at a specific temp
NaCl.dissolving.mov Ex: sol. of KNO3 is 60g at 40C So what do you mean “dissolve”?? If I heat up the water, will that help me dissolve more solute?
Remember: Solute- what you are dissolving (what you have less of) Solvation-process that occurs when ionic process dissolves
Solvent- what you are dissolving the solute in. Ex: water (what you have more of) Solution- homogeneous mixture of 2 or more subst. (the solUTE + solVENT!) SOLVENT SOLUTE
So…”If I stir more, will that help me dissolve more?” Based on the graph? NO! Makes it dissolve faster, but not more of it.
Solubility vs. Temperature
What term describes 39g NaCl at 70C? Saturated! What about 30g at same T? Unsat! What about 45g at same T? SUPERsat!
Solution Concentration
Does everything fit into those 3 vocab terms? What about %? (Parts per 100) in here… = PART WHOLE (* 100!)
Ex – what would % be of 5 grams of salt added to 95 g of water? Part = Whole
5 5+95 = 5 100 = 5%! But is 0.005% really helpful? So… also have ppm & ppb (million/billion) DEMO!
Becker Bottle demo is great here
Dissolving Ionic Compounds
From a MACROscopic perspective, we say salt is dissolved in water when we can’t see it any longer. But is that what is REALLY happening SUBmicroscopically? Water is POLAR. What does that make you think of? Polar bear maybe? North/south pole? Need to think like the earth’s poles – they are OPPOSITE each other
POLAR??? Polar basically means that the electrons that make up the molecule (water) are NOT spread out evenly. - - - - + + -
if more negative stuff is on 1 side, then that side will be PARTIALLY negative. Whole molc is still neutral!! Which side will be more negative: H or O? Explain!
SO what??
So.. If a molc has a slight + charge to it, what will it be attracted to? What could that have to do with dissolving?? What is table salt again?? What is the charge of each ion involved?
What does each color represent? Which side of the water will be attracted to the green chlorine ion? Will just one slightly + ion be able to pull the Cl- away from the Na+? What about a bunch of them?
NaCl.dissolving.mov Explain this diagram. What is this showing? “Aqueous Salt” (not liquid!) Crystal structure of NaCl SugarH2O_dissolve.mov NaCl.Aqueous.Soln.mov Look how ionic compounds dissolve! Why doesn’t it break up too?
So based on those pics & concepts, when will water be able to dissolve something? What if the charges btw the ionic cpd are too high for water to pull them away from each other? “INSOLUBLE”
WS Solubility Practice a curvy subject
NaCl.dissolving.mov Explain this diagram. What is this showing? “Aqueous Salt” (not liquid!) Crystal structure of NaCl SugarH2O_dissolve.mov NaCl.Aqueous.Soln.mov Look how ionic compounds dissolve! Why doesn’t it break up too?
So based on those pics & concepts, when will water be able to dissolve something? What if the charges btw the ionic cpd are too high for water to pull them away from each other? “INSOLUBLE”
Effects of Dissolving Compounds in Water PART 2
Rate of Dissolving Colligative and Electrolytic Properties
What if you are impatient? How can we speed up the dissolving process?
Well, what is causing it to dissolve? Interactions btw solvent & solute particles. So how to get more collisions? STIR HEAT Increase SURFACE AREA Explain…
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