16 - redox Flashcards
Define oxidation number
Number of electrons involved in bonding
What is an uncombined element?
Isn’t bonded to any other elements except itself
O~2 is uncombined
But H~2 O is combined
What is the oxidation number for an uncombined element?
Always 0
What is the oxidation number of combined oxygen?
-2
What is the oxidation number of combined hydrogen?
+1
What is a simple ion?
An ion from group 1 or group 17
What is the oxidation number of a simple ion?
The charge on the ion
What is the oxidation number of combined fluorine?
-1
An exception:
What is the oxidation number of hydrogen in a metal hydride?
-1 instead of +1
An exception:
What is the oxidation number of oxygen in peroxides?
-1 instead of -2
An exception:
What is the oxidation number of oxygen when it is bonded to fluorine?
+2 instead of -2
What does iron(III) chloride mean in terms of oxidation numbers?
The iron has an oxidation number of +3
What is an oxyanion and how do you identify one from a chemical name?
A negative ion with oxygen in it
They have “ate” at the end
What is unique about oxidation number of oxyanions?
The oxidation number refers to the thing in the oxyanion that isn’t oxygen
For example, phosphate’s oxidation number refers to the oxidation state of the phosphorus
What is the name of NO~2 -?
Nitrate(III) because the oxidation number of the nitrogen is +3
What do oxidation and reduction mean in terms of electrons?
Oxidation is loss of electrons
Reduction is gain of electrons
OIL RIG
What is a redox reaction?
A reaction where oxidation and reduction happen in the same reaction
What happens to oxidation number when a substance is oxidised?
Oxidation number goes up
If substance is reduced, oxidation number goes down
How do you work out which elements have been oxidised or reduced from a chemical equation?
You take the charge of the element in the products away from the charge of the same element in the reactants
What is a reducing agent and an oxidising agent?
Something that is oxidised is a reducing agent
Something that is reduced is an oxidising agent
I haven’t mistyped that
What is the name of NaClO?
Sodium chlorate
