FINALS T2: Redox Flashcards
Chemical reactions involves a change in the balance number of reacting substance.
it exchanges of electrons
Redox Reaction
4 types of Redox Titration:
Permanganometry
Iodimetry
Iodometry
Cerimetry
An element or compound that accept electrons are called?
w/ decrease valence or oxidation number
gain of electrons and hydrogen
loss of oxygen
Reduction/Reduced
An element or compound that donates electrons are called?
w/ increase valence or oxidation number
Loss of electrons and hydrogen
Gain of oxygen
Oxidation/Oxidized
how to write the oxidation half reaction of Na + Cl—-> +NaCl- ?
Na ——> (Na+) + (e-)
Cl + (e-) —–> (Cl-)
VILEORA MEANS?
Valence
Increase
Loss
Electron
Oxidation
Reducing
Agent
VDGEROA MEANS?
Valence
Decrease
Gain
Electron
Reduction
Oxidizing
Agent
the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.
oxidation number/ oxidation state
For the oxidation to happened, something must accept an electron (e-)
Oxidizing Agent
For the reduction to happened, something must donate a electron (e-)
Reducing Agent
1-3 Rules on oxidation numbers?
(1) The oxidation number of an atom in the elemental state is zero. Example: Cl2 and Al both are 0
(2) The oxidation number of a monatomic ion is equal to its
charge. Example: In the compound NaCl, the sodium has an oxidation number of 1+ and the chlorine is 1-.
(3) The oxidation number of oxygen in a compound is 2-, except in peroxides when it is 1-, and when combined
with fluorine, then it is 2+. Example: In H2O the oxygen is 2-, in H2O2 it is 1-.
4- 6 Rules on oxidation numbers?
(4) The oxidation number of Hydrogen is +1, except when bonded to metals in binary compounds. Example, in LiH, NaH, its oxidation # is -1
(5) the sum of a polyatomic is equal to it’s charge. Example: in the sulfate ion, SO4 2-,the oxidation numbers of the sulfur and the oxygens add up to 2-.
The oxygens are 2- each, and the sulfur is 6+.
(6) Sandwich elements get assigned last
ex: H2SO4 —–> H2 (2+) S (+6) O4 (-8) = 0
other Rules on oxidation numbers?
Fluorine has oxidation number of -1 in all its compounds. Other halogens (Cl, Br, and I) have negative oxidation
numbers when they occur as halide ions in their compounds. When they combine with oxygen they have
positive oxidation numbers Example Cl in HOCl
oxidation number:
Alkali metals (Na, K, Li): + 1
Akali earth metals (Mg, Ca, Ba, Sr): + 2
Redox titration that involves the use of permaganates and is used to measure the amount of analyte in the unknown chemical samples?
Permanganometry
what is the VS for Permanganometry?
Potassium Permanganate (KMnO4)
what is the primary standard for Permanganometry?
Sodium Oxalate (Na2C2O4)
A strong oxidizing agent
self indicating solution
mineral chameleon
Potassium Permanganate
(KMnO4) is instability in ?
*can be affected by light
*must not be used w/ Mohr burette cause it will attack the rubber on the burette.
(KMnO4) stain can be remove by what compound?
Oxalic Acid (C2H2O4)
what kind of Permanganometry is this chemical reaction?
5 H2O2 + 2 KMnO4 + 3 H2SO4 —–>
5 O2 + 2 MnSO4 + K2SO4 + 8 H2O
Direct Permanganometry
what kind of Permanganometry is this chemical reaction?
10 NaNO2 + 4 KMnO4 + 11 H2SO4 –>
10 HNO3 + 4 MNSO4 + 2 K2SO4 +
5 Na2SO4 + 6 H2O
Residual Permanganometry
Sample compound that undergoes a indirect permanganometry assay?
Malic acid in cherry juice (C4H6O5)
Titanium oxide (TiO2)
Manganese oxide (MnO2)
Sample compound that undergoes a Residual permanganometry assay?
Potassium nitrite (KNO2)
Salitre/ Sodium nitrite (NaNO2)
Types of redox titration that don’t have an indicator?
Permanganometry
What is the endpoint of the Permanganometry titration
The appearance of permanent pink colour
Assay of Hydrogen Peroxide/ Agua Oxigenada undergoes what kind of titration?
Direct Permanganometry
It is the quantitative analysis of a solution of an oxidizing agent by adding Iodide which reacts to form Iodine?
Iodometry
what is the VS for Iodometry?
Sodium thiosulfate [Na2S2O3] ( (w/ addition of Sodium bicarbonate (Na2CO3)
what is the primary standard for Iodometry?
Potassium Dichromate (K2Cr2O7)
what is the indicator for Iodometry?
Starch TS
a compound that acts to be a preservative in Starch TS indicator?
Red Mercuric iodide (HgI2)
what is the endpoint for Iodometry?
Blue to Colorless
Sample compound that undergoes a Residual Iodometry assay?
Phenol
Resorcinol
Lead Oxide (PbO)
Sample compound that undergoes a direct Iodometry assay?
Copper Sulfate (CuSo4)
Sodium hypochlorite (NaOCl)
Potassium hypochlorite (KOCl)
What compounds do form when you combine Potassium Iodide (KI) + Potassium Dichromate (K2Cr2O7) with addition of Sulfuric acid + Starch TS?
Importante cpmd: Iodine (I) + Starch=
(Starch- iodine complex)
Chromium sulfate [Cr2(SO4)3]
Potassium Sulfate [K2SO4]
Water
Starch- iodine complex appears to be what color?
blue
what compound is responsible for the disappearance of blue color in iodometry?
Sodium Tetrathionate (Na2S4O6)
what is the function of Sulfuric acid in redox titration?
catalyst
It is the quantitative analysis of a solution of reducing agent which is titrated directly with iodine solution
Iodimetry
what is the VS for Iodimetry?
Iodine solution
what is the primary standard for Iodimetry?
Arsenic Trioxide (As2O3)
what is the indicator for Iodimetry?
starch TS
what is the endpoint for Iodimetry?
Colorless to Blue
Sample compound that undergoes a direct Iodimetry assay?
Ascorbic Acid (C6H8O6)
Antimony Potassium Tartrate
(K2Sb2C8H4O12· 3 H2O)
Sample compound that undergoes a Residual Iodimetry assay?
Calomel
Antipyrine
Sodium bisulfite (NaHSO3)
Sodium sulfite (Na2SO3)
Residual Iodimetry assay? use what kind of titrant?
Sodium thiosulfate (Na2S2O3)
what do you called the official assay for ascorbic acid ?
Dichlorophenol-Indophenol
Analgesic + Antipyretic?
Antipyrine
All iodide should convert into iodine by using a reducing agent?
Iodometry or Iodimetry?
Iodimetry
what compound should be added to Iodine to increase it solubility?
Potassium Iodide (KI)
An Assay for sulfa drugs and other compound Arylamines
Not strictly an iodometric method: however the endpoint is determined by the liberation of iodine from iodide
reaction between a primary aromatic amine and nitrous acid to give a _____ compound
Diazotization Assay
Diazotization Assay VS (titrant) ?
Sodium Nitrite 0.1M (NaNO2)
Sample compound that undergoes a Diazotization assay?
Pyrimethamine
Benzocaine
Amino salicylic acid
Procaine
Procainamide
Dapsome
Sulfa drugs
Succinyl Sulfathiazole
Phthalysulfathiazole
In Diazotization assay, Sodium Nitrite 0.1M was converted into what compound?
Nitrous Acid (HNO2)
In Diazotization assay, it forms a byproduct called ?
Diazonium salt
also known as cerate oximetry, is a method of volumetric chemical analysis developed by Ion Atanasiu.
Cerimetry
what is the VS for Cerimetry?
Ceric Sulfate [Ce(SO4)2]
what is the primary standard for Cerimetry?
Arsenic Trioxide
what is the indicator for Cerimetry?
Orthophenanthroline TS
Sample compound that undergoes a Cerimetry assay?
Ferrous sulfate (FeSO4)
Menadianone/ VItamin K
Ferrous sulfate (FeSO4) USP recommendable percentage?
95%-110%
Menadianone/ VItamin K USP recommendable percentage?
98.5%-101%
Oxidizing Agent factor equals to “2”
Oxalic Acid (C2H2O4)
Sodium Hypochlorite (NaClO)
Oxidizing Agent factor equals to “6”
Potassium Bromate (KBrO3)
Potassium Dichromate (K2Cr2O7)
Oxidizing Agent factor equals to “1”
Ceric Sulfate [Ce(SO4)2]
Oxidizing Agent factor equals to “5”
Potassium Permanganate (KMnO4)
Reducing Agent factor equals to “2”
Ascorbic Acid (C6H8O6)
Menadianone/ VItamin K (C11H8O2)
Sodium Oxalate (Na2C2O4)
Hydrogen peroxide (H2O2)
Reducing Agent factor equals to “1”
Ferrous sulfate (FeSO4)
Sodium Nitrite (NaNO2)
Reducing Agent factor equals to “4”
Arsenic Trioxide (As2O3)
USP acceptable percentage range of Agua Oxigenda (H2O2)
2.5%- 3.5%
