Chem Unit 5 Flashcards
What is a redox reaction?
Oxidation-reduction reaction; electron transfer reaction
Oxidation means:
loss of electron(s) by a species; increase in oxidation number; increase in oxygen
Reduction means:
gain of electron(s); decrease in oxidation number; decrease in oxygen; increase in hydrogen
Oxidation number rules for free (uncombined) elements:
Always 0
Oxidation number rules for monoatomic ions:
Equal to the charge on the ion (Fe3+ –> 3+)
Oxidation number rules for hydrogen:
Always 1+, except when bonded to metals in binary compounds (-1)
NaH –> 1-
Oxidation number rules for Group I and II metals:
Always 1+ / 2+ respectively
Oxidation number rules for oxygen:
Always 2-, except with O-O bonds (peroxides) (1-)
In acidic solution, if you are missing an H during a half-equation balancing:
Add H+ to the side that needs it
In acidic solution, if you are missing an O during half-equation balancing:
Add H2O to the side that needs it, and 2H+ to the other side
In basic solution, if you are missing an H during half-equation balancing:
Add H2O to the side that needs it, and OH- to the other side
In basic solution, if you are missing an O during half-equation balancing:
Add 2OH- to the side that needs it, and H2O to the other side
carbonate
Characteristics of acids:
- Sour
- Turns blue litmus reD
- Reacts with some metals to produce H2
- Dissolves carbonate salts to produce CO2
Coffee, citrus…
Characteristics of bases:
- Bitter
- Turn red litmus Blue
- Slippery
Soap, bleach…
Arrhenius acids/bases suggest:
Acids form H+, bases form OH-
Brownsted-Lowry acids/bases suggest:
Acids are proton DONORS, bases are proton RECEIVERS
What does H+ really represent?
[H3O]+
A “naked” proton will not exist in water, it is very small and very positively charged
Binary acid?
A binary acid is a molecular compound made up of hydrogen and a nonmetal element.
Oxyacid?
any oxygen-containing acid
Organic acid?
An organic acid is an organic compound with acidic properties. Organic acids contain carbon atoms in their structure.
Organic acids are generally weak acids.
Mono-, di-, tri-, polyprotic acid?
Acids with one, two, three, or 2+ protons to donate
What are conjugate pairs?
Every time a Bronsted-Lowry acts as a proton donor it forms a conjugate base and vice versa.
HA + H2O ⇌ H3O+ + A-
A- is the conjugate base.
Amphiphrote?
Molecules or ions which can either donate OR accept a proton, depending on their circumstances are called amphiprotic species.
Keyword: IONIZE
Strong acids?
- Ionise completely (>99%)
- HA → H+ + A-
- Strong Acids → Weak Conjugate Bases
HCl
H2SO4
HNO3
Weak acids?
- <99% ionization
- HA ⇌ H+ + A-
- Weak Acids → (Relatively) Strong conjugate Bases
Organic acids (CH3COOH)
H2CO3
Strong bases?
- Dissociate completely (>99%)
- MOH → M+ + OH-
- Strong Bases → Weak Conjugate Acids
Group 1 hydroxides (NaOH)
Ba(OH)2
Weak bases?
- Dissociate Partially (<99%)
- B(aq) + H2O(l) ⇌ BH+(aq) + OH-(aq)
- Weak Bases → (Relatively) Strong Conjugate Acids
All other bases except Group 1 and 2 are WEAK
Pyridine
pH =
- -log[H+]
- 14 - pOH
Acids containing H+ and a monoatomic ion are called:
binary acid
hydro ____ ic acid
HCl = hydrochloric
Acids containing H+ and an -ite polyatomic are called:
__ous acid
H2SO3 = sulfurous
Acids containing H+ and an -ate polyatomic are called:
__ic acid
H2SO4 = Sulfuric
Acids containing H+ and one more oxygen than an -ate polyatomic are called:
per__ic acid
H2SO5 = persulfuric
Acids containing H+ and two less oxygen than an -ate polyatomic are called:
hypo__ous acid
H2SO2 = hyposulfurous
How to find net ionic equation?
Write everything out as ions with charges on both sides. Anything with an unchanged charge is a spectator.
