categories of chemical reaction Flashcards
what reactions are considered non-redox?
1) combination (synthesis)
2) double replacement: precipitation, acid base and gas evolution
3) decomposition
what reactions are redox?
1) combination (synthesis)
2) single replacement reaction
3) decomposition
4) combustion
why are single replacement reactions and combustion reactions redox?
the oxidation state of at least one atom species changes through electron transfer on either side of the equation
what are gas evolution reactions?
acid-base reactions producing gas due to instability of an intermediate salt product
what are spectator ions?
ions in a replacement reaction that don’t undergo any changes and remain ionised in aqueous solution
what is a precipitation reaction?
a reaction which involves ions which exchange partners or may form precipitates depending on solubility
what is oxidation?
either an increase in oxidation number or loss of one or more electron
what is reduction?
decrease in oxidation number or gain of one or more electrons
what is required for a redox reaction?
oxidation and reduction must occur simultaneously
how are oxidation states assigned to elementary substances?
the oxidation state of an uncombined element is always zero
how are oxidation states assigned to monoatomic ions?
oxidation state is equal to charge
how are oxidation states of neutral molecules determined?
the sum of the oxidation numbers of the elements which make up the molecule equal zero
in polyatomic ions - sum is equal to charge
what is the oxidation number of hydrogen?
+1 except when in metal hydrides, where it is -1
what is the oxidation number of Oxygen?
-2 except:
peroxides -1
OF2 +2
superoxides -1/2
what is the oxidation number of alkali metals?
+1
