Redox Reactions: Energy Producing Reactions

Question 1

Energy producing reactions

Answer 1

• Energy is required for 3 major purposes
• Muscle contraction and other cellular movements
• Active transport of molecules and ions
Synthesis of macromolecules and other biomolecules

Question 2

Oxidation occurs when a molecule

Answer 2

Loses electrons
Loses hydrogens
Gains oxygen

Question 3

Reduction occurs when a molecule

Answer 3

Gains electrons
Gains hydrogen
Loses oxygen

Question 4

Reducing agent

Answer 4

a molecule undergoes oxidation it has been oxidized

Question 5

Oxidising agent

Answer 5

a molecule undergoes reduction, it has been reduced

Question 6

The rules to assign oxidation number

Answer 6

The oxidation number of oxygen is usually -2 unless its in a peroxide. The oxidation number of hydrogen is +1 except when it is bonded to metals in binary compounds. In these cases, its oxidation number -1.Group IA metals are +1, IIA metals are +2 and fluorine is always -1Oxidation numbers do not have to be integers. The oxidation number of oxygen in the superoxide ion O2- is 1/2

Question 7

How to balance redox reactions

Answer 7

Determine what is oxidised and what is reduced.
Write 2 half reactions and balance all the atoms other than O and H in each half reaction.
For reactions in acidic medium, add H2O to balance O atoms and h+ ions to balance H atoms. For a basic medium for every. H+ ions add an equal number of OH- ions to both sides of the equation.
Add electrons to each half-reaction to balance the charge.
Must have the same no. electrons in each half reaction.