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)