4.1 Solutions and Electrolytes - Solubility rules Flashcards
What is an aqueous reaction?
A reaction that takes place in water
What is solution?
Solvent + Solute
So something dissolved in a liquid
Solvent
What the solute is dissolved in
It is usually a liquid and present at a higher concentration than any of the solutes
Solute
Thing dissolved in the solvent
What do fish breath?
* They breathe O2 just like we do. This O2 is actually dissolved in water
* This is a gas solute dissolved in H2O
* So if you cover up your fish bowl, the O2 from the atmosphere cant get in and dissovle into the water, so the fish will die
* so you can have gases dissolved in water
Electrolytes:
Water is actaully not electrically conductive when it is pure. However, if there are electrolytes dissolved in that water it makes it electrically conductive
Electrolytes = anything that dissassociates into ions when it dissolves in water
* not everything that is dropped into water will dissassociate into ions, but the ones that do are called electrolytes
* the more ions the h2o has in it the more electrically conductive that water will be
Electrolytes: Anything when introduced to water disassociates into ions
Strong electrolytes: When dissolved in water dissasociate larely into ions - there are 3 types of strong electrolytes:
1) Soluble Ionic Compounds
* So this is metal and non metal, or something + polyatomic ion
* Think NaCl - but how do we know which ones are soluble? Wel cover this later, but think about table salt, just from experience you know this dissolves pretty fully in water = strong electrolyte
2) Strong Acids - acids that dissolve a lot in water
* Remember, acids begin w/ an H
* Strong Acids = HCl, HBr, HI, HClO4, HClO3, H2SO4, HNO3
* This is helpful because now that we have the strong acids memorized, everything thats not these is considered weak acids
3) Strong Bases - bases that dissolve a lot in water
* So these are all hydroxides, and mostly group 1 and group 2
* LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
Weak electrolytes:
1) Weak acids - you recignize these by knowing the strong acids and seeing that its not one of them
* If he gave me something like HF, then i can identify it as an acid by seeing that it starts w/ an H and it isnt one of the strong ones = weak acid
* CH3COOH = organic acid - this is the one that we basically need to memorize and know that its an acid even though it doesnt begin w/ an H. Know its a weak acid - end w/ COOH. Anything ending w/ COOH = weak acid
2) Weak bases - NH3, CH3,NH2 - so typically these are going to to have something either is or looks like ammonia in it (NH3)
Nonelectrolytes: - these might dissolve in water, but they dont dissassocite into ions when they do. = non electrically conductive at all
* Way to recignize = they arent acids, they arent bases, they arent ionic compounds - they’re molecular compounds (all non metals and no polyatomic ions). - keep in mind some acids and bases are entirely non metal (remember hydrogen doesnt count as a metal) but you have to be able to identify these and diliniate them out.
* CH3OH - this is an alcohol (dont mix it up w/ week acids that end in COOH) - so its a molecular compound
* C6H12O6 - all non metals and molecular compound - will dissasociate into water but because its covalent there arent charges, so it won’t be ionic - its a molecular compound = nonelectrolyte
What are out 7 storng acids?
These are acids that are very likely to dissassociate in water (making electrolytes)
1) HCl
2) HBr
3) HI
4) HClO4
5) HClO3
6) H2SO4
7) HNO3
What are our 8 strong bases?
These are bases that are very likely to disassociate in water making electroyltes
1) LiOH
2) NaOH
3) KOH
4) RbOH
5) CsOH
6) Ca(OH)2
7) Sr(OH)2
8) Ba(OH)2
These are easy because they all have hydroxide in them and they are all in group 1 or 2
Compound ends w/ COOH, what is it?
Weak acid
CH3COOH = weak acid
* the only acid we have to remember that doesnt start w/ an H
What do weak bases look like?
NH3 - ammonia
might have NH2 in it, just something that resembles this
* think CH3NH2
Solubility Rules (for ionic compounds in water)
By looking at the anions you can tell if something is soluble or not
Soluble Ionic Compounds (meaning if the ionic compound has one of these anions in it its solbule)
* NO3-, CH3COO- = no exceptions
* Cl-, Br-, I- = Exceptions (Ag+, Hg2^2+, Pb^2+)
* SO4^2- (Exceptions: Sr^2+, Ba^2+, Hg2^2+, Pb^2+)
What are our two ionic anions that make every thing they combine w/ soluble?
NO3-
CH3COO-
Theres no exceptions to these guys
* Ways they’re written in compouns
* NaCH3CO2
* AgNO3
What cations make the anions Cl-, Br-, I- insoluble?
Meaning if they combine w/ these they wont dissolve in water. However, in any other ionic compound these will be soluble dissolving in water
Ag+
Hg2^2+
Pb^2+
Ag+, Hg2^2+, Pb^2+ are all cations that make these anions insolbule (3)
Normally and substance that has these 3 cations in them is solbule in water (dissassociates). However, not when they’re combined w/ the exceptions above
Cl-
Br-
I-
SO4^2- makes almost any ionic compound soluble in water. However, when its combined w. these 4 exceptions it is insoluble in water. What are the 4 exceptions?
Sr^2+
Ba^2+
Hg2^2+
Pb^2+
Which anion when combined w/ Sr^2+, Ba^2+, Hg2^2+, Pb^2+ is insoluble, but any other time makes the ionic compound solbule?
SO4^2- sulfate
Insoluble Ionic Compounds
* S^2- (Exceptions: NH4^+, Group 1, Ca^2+, Sr^2+, Ba^2+
* CO3^2- (exceptions: NH4^+, Group 1)
* PO4^3- (exceptions: NH4^+, Group 1)
* OH- (Exceptions: NH4^+, Group 1, Ca^2+, Sr^2+, Ba^2+)
Typically an ionic compound is insoluble if it has the anion S^2- in it. However, what are its 5 exceptions?
1) NH4^+
2) Group 1
3) Ca^2+
4) Sr^2+
5) Ba^2+
Typically any ionic compound when combined w/ the Anion CO3^2- (carbonate) is insoluble. However, when combined w/ these two exceptions its actually soluble, what are the exceptions?
NH4^+, Group 1
PO4^3- is an anion that typically makes any substance its combined w/ insoluble, however, when combined w/ these two exceptions the ionic compound is actually solbule
1) NH4^+
2) Group 1
OH- is an anion that typically makes the ionic compound its in insoluble, however when these 5 exceptions its soluble in water
1) NH4^+
2) Group 1
3) Ca^2+
4) Sr^2+
5) Ba^2+
What are our 4 anions that make ionic compounds insoluble?
S^2-
CO3^2-
PO4^3-
OH-
