Physical 1: Redox Flashcards
what is oxidation?
the loss of electrons OR the gain of oxygen OR the loss of hydrogen
what is reduction?
the gain of electrons OR loss of oxygen OR gain of hydrogen
what is an oxidising agent?
species that gains electrons
what is a reducing agent?
species that loses electrons
define oxidation state
a number which represents the number of electrons lost or gained by an atom of that 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
what is the oxidation state of hydrogen in KH?
[H] = -1
what is the oxidation state of chlorine in NaClO?
[Cl] = +1
define the term disproportionation?
where in a redox reaction, the oxidation states of atoms of the same element, increases for some atoms, whereas decreases for some atoms
what is the oxidation state of phosphorus in PCl5
[P] = +5
what is the oxidation state of nitrogen in ammonia?
[N] = -3
what is the oxidation state of arsenic in AsO4^-3
[As] = +5
what is the oxidation state of iron in K4Fe(CN)6?
[Fe] = +2
why is 1s^2 2s^2 2p^5 a weaker reducing agent than 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2?
the 2p electron is closer to the nucleus (smaller atom) than the 4s electron. Hence 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 to another
- one element is oxidised whilst another is reduced
