Review the learning goals and success criteria for Topic 2a: Balancing Redox Reactions with Oxidation Numbers.
Review the minds on, action, and consolidation sections of the lesson, completing any tasks as outlined.
Complete the fill-in-the-blanks handouts that have been provided to you. They have been linked below.
Practice and apply what you've learned by completing the practice tasks outlined at the end of the lesson.
I am learning to ...
balance complex redox reactions using oxidation numbers in aqueous solutions.
balance redox reactions in acidic and basic solutions.
Most simple redox reactions can be balanced by inspection.
For more complex reactions, we can use either of two methods:
Oxidation Numbers Method (this lesson)
Half Reactions Method (the next lesson)
For redox reactions, the CHARGE must be balanced, in addition to each element.
Determine the oxidation numbers for each element in the equation and identify the elements for which the oxidation numbers change.
Adjust the values of the coefficients to balance the electrons transferred.
Balance the rest of the equation by inspection. If necessary, balance oxygen by adding H2O.
If necessary, balance hydrogen by adding H+ and/or OH-.
Check your answer.
Write the balanced equation.
Redox reactions often take place in aqueous solutions, which can be: acidic, basic, or neutral.
Therefore, when balancing, you may need to include: H2O, H+ or OH-.
THIS REACTION TAKES PLACE IN ACIDIC SOLUTION.
THIS REACTION TAKES PLACE IN BASIC SOLUTION.
Attempt some of the questions below and then compare your answer with the solutions provided.
Use the Oxidation Number Method to balance the following equations:
a) Al(s) + MnO2(s) → Al2O3(s) + Mn(s) [Show Answer]
b) SO2(s) + HNO2(aq) → H2SO4(aq) + NO(g) [Show Answer]
c) HNO3(aq) + H2S(aq) → NO(g) + S(s) + H2O(l) [Show Answer]
d) Al(s) + H2SO4(aq) → Al2(SO4)3(aq) + H2(g) [Show Answer]
e) Cr2O72-(aq) + Cl-(aq) → Cr3+(aq) + Cl2(aq) (in acidic solution) [Show Answer]
f) MnO4-(aq) + SO3-(aq) → SO42-(aq) + MnO2(s) (in basic solution) [Show Answer]
This lesson is now complete. Consolidate your learning by evaluating the self-check below and the assigned practice questions.
How prepared am I to start my homework? Can I ...
balance complex redox reactions using oxidation numbers in aqueous solutions?
balance redox reactions in acidic and basic solutions?
Using your textbook, complete the following questions:
p613 # 1-6
p617 # 3, 4