oxidation, reduction and redox equations Flashcards
(32 cards)
What are redox reactions?
Electron transfer reactions requiring movement of electrons.
What is oxidation?
Process of electron loss, increase in oxidation number, gain of oxygen.
What is reduction?
Process of electron gain, decrease in oxidation number, loss of oxygen.
What is an oxidising agent?
Accepts electrons, causes oxidation, gets reduced.
What is a reducing agent?
Donates electrons, causes reduction, gets oxidised.
In the reaction 2Mg + O2 → 2MgO, what is the reducing agent?
2Mg
In the reaction 2Mg + O2 → 2MgO, what is the oxidising agent?
O2
What do oxidation states indicate in a redox reaction?
What has been oxidised and what has been reduced.
What is the oxidation state of elements in their elemental form?
0
What does a positive oxidation state indicate?
The element has lost electrons and has been oxidised.
What does a negative oxidation state indicate?
The element has gained electrons and has been reduced.
What must the sum of oxidation states in a compound equal?
0
What is the oxidation state of Group 1 elements?
+1
What is the oxidation state of Group 2 elements?
+2
What is the oxidation state of aluminum in compounds?
+3
What is the oxidation state of oxygen in peroxides?
-1
What is the oxidation state of hydrogen in metal hydrides?
-1
What is the oxidation state of fluorine?
-1
What is a half equation?
Shows the transfer of electrons in a redox reaction.
What happens in disproportionation reactions?
Atoms of the same element are both oxidised and reduced.
What are the steps to balance redox equations?
- Write half equations 2. Balance atoms 3. Balance charges by adding electrons 4. Combine equations.
In aqueous solutions, how do you balance oxygen in redox equations?
By adding H2O molecules on the opposite side.
In aqueous solutions, how do you balance hydrogen in redox equations?
By adding H+ ions on the opposite side.
What indicates an increase in oxidation number?
Oxidation
