Catalyst and Activation Energy

Catalyst A catalyst is a substance that speeds up a chemical reaction but it does not undergo a chemical reaction itself. The catalyst allows the reaction an alternative pathway to take place. The catalyst does not lower the activation energy of the reaction. Analogy

Reaction Coordinate Diagram

Given the following reaction, sketch a reaction coordinate graph. The reaction involves two steps, step 1 is the slowest step and step 2 is the fastest step. Indicate on the diagram the overall enthalpy change of the reaction, the reaction for the transitions states and intermediate states.

H2(g) + 2ICl(g) –> 2HCl(g) + I2(g)

Integrated Rate Laws

Overview The differential rate law relates the change in concentration of a reactant over a specified time. In other words, it tells us about the overall rate of a reaction from the beginning to the end of the reaction and the rate law also tells us how the speed of a reaction is impacted by […]

Rate of reaction

Measuring rate This section aims to cover the following topics: Define chemical reaction rate Define rate expression Relative rates of reaction and stoichiometry ratio Change in concentration over time The rate of a chemical reaction can be thought of as the speed at which a chemical reaction happens and this can be expressed as the […]

Mechanisms and Intermediates

Reaction mechanism Chemical reactions often take place in multiple steps and it’s not always obvious from looking at the chemical equation. For example, the decomposition of ozone: From the equation, it appears that O₃ decomposes to O₂ in one step. In reality, it’s more likely to take place in the following sequence: The above shows […]

Introduction to Chemical Kinetics

Energy Kinetics involves studying what makes chemical reactions happen. Every reaction that happens involves some energy exchange, whether it’s slow reaction such as iron rusting, or a faster reaction, such as when a rocket burns fuel during take off.  Size of particles Pictures in the slider: (CC BY-SA 3.0) | Link: | Author: Hans-Peter […]