Redox Equations & Titrations

4 Steps to Solve Redox Reactions in JC A-Level H2 Chemistry

April 12, 2018 By Sean Chua Leave a Comment

Solving Redox Reactions - A Level H2 Chemistry Tuition Class — Photo Credit: Paul (Creative Commons)

Many students in my weekly JC1 GCE A-Level H2 Chemistry Tuition Classes in Singapore told me that they are struggling to understand the concepts regarding Redox Reactions. This is usually taught in JC1 Topic 1: Mole Concepts & Stoichiometry in their Junior College’s lectures and tutorial classes. They seems lost and don’t even know how to start when looking at a Redox Reactions question.

Many of them have approached their JC teacher or recommended H2 Chemistry tutor but still not able to solve redox reactions question confidently.

So, before you work on another Redox Reactions question, do go through the following:

4 steps on How to Solve Redox Reactions

1. Describe and explain redox processes in terms of electron transfer and/or of changes in oxidation number (oxidation state)

Reduction and Oxidation processes may be defined in terms of electron transfer and/or changes in oxidation number (oxidation state).

Reduction: A process whereby a substance gains electrons, resulting in a decrease in oxidation number
Oxidation: A process whereby a substance loses electrons. resulting in an increase in oxidation number
Reducing Agent (Reductant): A substance that gives electrons to another, itself being oxidised in the process
Oxidising Agent

13 Steps Strategy to Balance Redox Equations in Alkaline Medium Video

April 24, 2017 By Sean Chua Leave a Comment

In the previous blog post, i have shared with you on the strategies to balance redox equations using the Half-Reaction Method in acidic medium. If you have missed out on that, you should click HERE to view the video teachings.

Today, we are going to continue to use the Half-Reaction Method to balance redox equations in the alkaline medium.

13 Steps Strategy to Balance Redox Equations in Alkaline / Basic Medium:

Following are the strategy when you need to balance redox equations in the alkaline medium:

1: Using the O.S., identify the oxidised and reduced species

2: Construct a half-reaction for the oxidation step & balance the no. of atoms oxidised

3: Balance O by adding H₂O

4: Balance H by adding H⁺

5: Add to both sides of the equation the same no. of OH^– as there are H⁺ (alkaline medium)

6: Combine H⁺ & OH^– to form H₂O

7: Cancel any extra H₂O

8: Balance charges by adding electrons

9: Oxidation half-reaction equation is now balanced

10: Repeat step 2 to step 9

11: Reduction half-reaction equation is now balanced

12: Combine the two half-reaction … Continue reading ...

10 Steps Strategy to Balance Redox Equations in Acidic Medium Video

April 19, 2017 By Sean Chua Leave a Comment

Redox equations are often so complex that many Chemistry students have a hard time balancing them with stoichiometry coefficients. I observed that many of my students who recently join us in the JC1 Higher 2 (H2) Chemistry Tuition Classes are pretty weak (some don’t even know how to start the question) when it comes to balancing redox equations. Several mentioned that they don’t understand what their H2 Chemistry lecturers / recommended H2 Chemistry Tutors are teaching them in the lectures and tutorials. So today, we will be looking at the 10 Steps Strategy to Balance Redox Equations in Acidic Medium.

Note that it is actually not that difficult to balance the equations. You just need some strategies/procedures and some practice will make it perfect.

Also, do note that it is very important for students to be able to balance redox equations, because we need it in order to solve redox titrations type of questions which is very common in Advanced Chemistry syllabus (i.e. GCE A-Level H2 Chemistry).

Chemists have developed the Ion-Electron (Half-Reaction) method which we will be discussing today. Do note that there’s an alternative method called the Oxidation Number method which we will discuss another time.… Continue reading ...