  I got a 7 for my Chem SL IA in 2021. the topic was “To investigate how changing the concentration of hydrogen peroxide affect the rate of oxidation of iodide ions using the iodine clock reaction.”

[Sample excerpts]

### Aims

To investigate how changing the concentration of hydrogen peroxide affect the rate of oxidation of iodide ions using the iodine clock reaction.

### Research Question

How does changing the concentration of hydrogen peroxide affects the rate of oxidation of iodide ions using iodine clock reaction?

### Introduction

There are a lot of ways to affect the rate of reaction such as catalyst, temperature, pressure, particle size and concentration. During the school chemistry class, I learned that increasing concentration of reactant will increase the number of particles per unit volume such that there are more collisions per unit of time, increasing the rate of reaction. However, I got curious about why in HL Chemistry, there is a concept of zero-order, where the reaction rate is independent of concentration. This led me to question whether the concentration of reactants in the well-known iodine-clock reaction may also affect the reaction rate or not. In an attempt to answer a part of my question, I decided to investigate the effect of changing the concentration of the hydrogen peroxide, one of the reactants of iodine-clock reaction, on its rate. “Clock” reaction method was used, which involves using the formula [I2 used up]/t, and t can be time for the reaction to complete, but in this context is when the color of the solution changes from colourless to blue-black color.

### Background Information

The collision theory1 states that for a reaction between two particles to occur, the particles must collide in the appropriate orientation with energy greater than the activation energy (minimum amount of energy required for a reaction to proceed). The rate of reaction2 refers to the rate at which the concentration of a reactant/product decreases/increases. The rate of reaction between two reactants, A and B, is found to be proportional to the concentration of A and B each raised to a power: Rate = []![]” where x and y are the order of the reaction with respect to A and B and k is the rate constant.

The iodine clock reaction is a chemical clock demonstration experiment to show the chemical kinetics in action. The idea of its mechanism is that mixing of two colourless solution will provide the solution of blue- black colour…

• Total number of pages: 12 pages
• Topic: How changing the concentration of hydrogen peroxide affect the rate of oxidation of iodide ions using the iodine clock reaction
• Subject: Chemistry
• The file is in PDF format.