Reactions- L12 Flashcards
Cr
2, 3, 4, 6
Mn
2, 3, 4, 6, 7
Fe
2, 3
Co
2, 3
Ni
2
Cu
1, 2
Zn
2
Ag
1
Au
1, 3
Hg
1, 2
Solutions
- a homogeneous mixture of a solvent and solute
- solvent- more and does the dissolving
- solute- less and gets dissolved
- Aqueous solution- solutions in which water is the solvent
Electrolytic solutions
- An ionic compound dissolved in a polar solvent
- Has to have charged parts to dissolve
- most ionic compounds do this
- If a solution conducts electricity it must contain ions
- The more ions the solution contains, the better able it is to conduct electricity
Draw representation of dissolved ionic compound
- Draw 2 circles with one element in each
- exaggerate relative sizes of the nucleus
- Include charges in those circles
- Draw water molecules around it with dipoles
- O= -
- H= +
ions in water/conducting electricity
- smaller ions move slower since they attract and drag more water
- Larger ions move faster since they are less attracted to the water, greater shielding effect and coulombs law
Molecular compounds in water
- molecular= no metals in it
- Non-electrolytes= most molecular compounds do not dissolve in water and therefor do not conduct electricity (sugar, methanol)
- Weak-electrolyes= weak acids- some dissociation (low conductivity), ex. acidic acid CH3COOH (aka ethanol acid or vinegar)
- Strong-electrolytes= strong acids- complete dissociation (high conductivity) ex. hydrochloric acid (HCl), HF, HNO3, H2SO4 (first H is strong, second is weak)
Like dissolves like
- Non polar molecules dissolve in non polar solvents
- polar molecules dissolve in polar solvents
- ex. water and methanol
Precipitation reaction
- aka double replacement, double displacement, ionic
- In a precipitate reaction, the attractive forces between oppositely charged ions is greater than the forces of attraction between H2O molecules and ions
- products are an aqueous and solid
Write the balanced net ionic equation for a precipitate reaction
- Write out the equation
- break down of reactants ==> recombined, not combining the dissolvable
- Balanced Net ionic equation only shows the reaction that actually took place (not including dissolved)
- Complete ionic equation shows all of the species that are present (includes dissolvable combined into compounds)
Solubility rules
- All salts (ionic compounds- cation and anion) containing Na+, K+, NH4+, or NO3-
- All alkaline metals
- All nitrates and ammonium
Pb
+2
Oxidation Reduction Reactions
- Aka REDOX reactions
- Electron transfer reactions
- One substance gets oxidized and loses electrons
- The other substance gets reduced and gains electrons
Single Replacement REDOX reactions
- Element and compound
Rules for determining oxidation numbers- atom in its elemental form
its oxidation number is zero
Rules for determining oxidation numbers monoatomic ion (like Mg+2)
oxidation number equals its charge
Rules for determining oxidation numbers- oxygen
- -2 in any molecular compound
- Exception in peroxides= -1. ex. H2O2
Rules for determining oxidation numbers- Hydrogen
- +1 when bonded to a nonmetal
- -1 when bonded to a metal
Rules for determining oxidation numbers other covalent bonds that do not contain H or O
- the most electronegative element has an oxidation number equal to its charge as an ion
- ex. F=-1 in BF3 and Cl= -1 in PCl5
Rules for determining oxidation numbers sum of oxidation numbers
- must equal the overall charge of that compound
- ex. must equal 0 in H2O and -1 in ClO3-
Oxidized
- OIL
- electrons lost
- More positive
Reduced
- RIG
- electrons gained
- more negative
Which solution in each set is the better conductor of electricity?
- The one with the most ions
- must be ionic compound
write the balanced chemical equation for the dissolving of aluminum nitrate in water
- the compound breaks down into separate elements
- Al(NO3)3 (s) ==> Al+3 (aq) + 3NO3- (aq)
Write the balanced net ionic equations for the reactions
- write out equation ==> broken elements
- take out soluble elements to get final
Hydrogen peroxide is both
oxidized and reduced
