6.2.5-6.2.7

6.2.5 Sketch and explain qualitatively the Maxwell–Boltzman energy distribution curve for a fixed amount of gas at different temperatures and its consequences for changes in reaction rate


This video explains fully the the energy distribution curve.


It is said that the Boltzman distribution shows the distribution of molecular energy in a gas. It also points out the factors that are apparent in the distribution curve

• No molecules at zero energy.
• Few molecules at high energy 
• No maximum energy value

For the reaction to occur, the particles involved need a minimum amount of energy - the Activation energy. If a particle is not in the shaded area, then it will not have the required energy so it will not be able to participate in the reaction. In this sense the peak at the curve shows that there are many particles with few kinetic energy to the activation energy. In different temperatures however for example if the temperature was increased then the curve will more likely be broader and flatter. This means there are now more molecules with sufficient kinetic energy, but this does not change the activation energy, only the frequency. 

6.2.6 Describe the effect of a catalyst on a chemical reaction.
Catalysts will reduce the activation energy by providing an alternative pathway that requires the less energy for the reaction to occur. The use of a catalyst will therefore speed up the rate of reaction while the catalyst (chemically) remains unchanged, it can however change states. These catalysts provide a platform for which the molecules will react or an active site. Although unchanged, with increased temperature the catalyst becomes denatured.


6.2.7 Sketch and explain Maxwell– Boltzmann curves for reactions with and without catalysts.




This is also a video where water catalyzes the reaction: