redox (physical) Flashcards
What is oxidation
The loss of electron
gain of oxygen (or any electronegative element)
loss of hydrogen (or any electron positive element)
What is reduction
Gain of electrons
Loss of oxygen (any electronegative element)
Gain of hydrogen (any electropositive element)
What is an oxidising agent
Species that gains electrons
What is a reducing agent?
Species that lose electrons
What are the half equations and the ionic equations for:
SnO + Zn -> ZnO + Sn
Half equations:
Sn²+ + 2e‐ -> Sn
Zn -> Zn²+ + 2e-
Ionic equations:
Sn²+ + Zn -> Sn + Zn²+
Define oxidation state
A number which represents the number of electrons lost or gained by an atom of the element in the compound
(if electrons are lost, number is positive. If electrons are gained, number is negative)
What is the oxidation state of oxygen in OF²
[O] = +2
otherwise [O] is -2 in all other compounds
What is the oxidation state of hydrogen in KH-¹
[H] = -1
What is the oxidation state of chlorine in NaClO
[Cl] = +1 (-1 in all compounds except O and F)
Define the term disproportionate
Where in a redox reaction, the oxidation states of atoms of the same element, increase for some atoms, whereas decrease for some atoms
Whats the oxidation states of phosphorus in PCl⁵
[P] = +5
What is the oxidation state of iron in K⁴Fe(Cn)⁶
[Fe] = +2
Why is 1s²2s²2p⁵ a weaker reducing agent than 1s²2s²2p⁶3s²3p⁶4s²
The 2p electron is closer to the nucleus than the 4s electron. Here the nuclear attraction is stronger so the 2p electron is lost less easily than the 4s electron
What happens in a redox reaction
Electrons are transferred from one species (element) to another.
One element is oxidised whilst another is reduced
Why is 2CrO⁴ ²- + 2H+ > Cr²O⁷ ²- + H²O not a redox reaction
Chromium is oxidised whereas hydrogen remains the same oxidation state (no element is reduced)
