2.1.5 Redox Flashcards
What is the oxidation number of an atom in its natural form?
0
What is the oxidation number of oxygen in peroxide?
-1
What is the oxidation number of hydrogen in metal hydrides?
-1
What is the oxidation number of group 1 and 2?
+1, +2
What is the oxidation of fluorine in compounds?
-1
How do you determine the oxidation number of an element in a molecular (covalently bonded) ion?
The sum of the oxidation numbers of all elements in the ion equal the charge of the ion
How do you write the formula for a compound with elements of known oxidation numbers
Balance oxidation numbers to make the sum of the oxidation numbers equal to zero or to the charge of the ion
How is oxidation number indicated for elements with multiple oxidation states?
Roman Numerals
What are formulas for Iron (II) chloride and Iron (III) chloride?
FeCl2 (Fe has oxidation number +2)
FeCl3 (Fe has oxidation number +3)
What is oxidation and reduction in terms of electron transfer?
Oxidation - loss of electrons
Reduction - gain of electrons
What is oxidation and reduction in terms of oxidation number?
Oxidation - increase in reduction number
Reduction - decrease in oxidation number
What happens in reaction:
2Mg + O2 → 2MgO
Mg is oxidised from 0 to +2
O is reduced from 0 to -2
What happens in reaction:
4Fe + 3O2 → 2Fe2O3
Fe is oxidised from 0 to +3
O is reduced from 0 to -2
What products form when a metal reacts with an acid?
Salt and hydrogen gas
What is the reaction between magnesium and hydrochloric acid?
What is being oxidised and what is being reduced?
Mg + 2HCl → MgCl2 + H2
Mg is oxidised 0 to +2
H is reduced from +1 to 0
What is the reaction between zinc and hydrochloric acid?
Zn + 2HCl → ZnCl2 + H2
Zinc is oxidised 0 to +2
H+ is reduced +1 to 0
What is the reaction between Iron and hydrochloric acid?
Fe + 2HCl → FeCl2 + H2
Iron is oxidised 0 to +2
H+ is reduced +1 to 0
How do you interpret a redox equation
Assign oxidation numbers, identify which elements are oxidised and reduced, and track electron loss or gain
How can you predict the products of a redox reaction?
By identifying the oxidation states of the reactants, you can predict which elements will be oxidised and reduced, and determine the products
