Module 2 - Redox

Question 1

oxidation number rules

Answer 1

uncombined element is always 0
group 1 is +1
group 2 is +2
halogen is -1
hydrogen is +1
oxygen is -2
sum of oxidation numbers is 0
sum of oxidation number is equal to charge on the ion

Question 2

oxidation def

Answer 2

loss of electrons
Cu2+ + Mg –> Cu + Mg2+
Magnesium has been oxidised (lost electrons)

Question 3

reduction def

Answer 3

gaining of electrons
Cu2+ +Mg –> Mg2+ + Cu
Copper has been reduced (gained electrons)

Question 4

oxidation in terms of oxygen

Answer 4

Cu+H2O->CuO+H2
Copper has been oxidised and has gained an oxygen atom

Question 5

reduction in terms of oxygen

Answer 5

CuO+H2->Cu+H2O
Copper oxide has been reduced to Copper

Question 6

what is a redox reqction

Answer 6

reactions in which oxidation and reduction take place together