Why do rates of reaction matter in industry

Increasing the temperature of a system increases the average kinetic energy of its constituent particles. As the average kinetic energy increases, the particles move faster and collide more frequently per unit time and possess greater energy when they collide. Both of these factors increase the reaction rate. Hence the reaction rate of virtually all reactions increases with increasing temperature. Conversely, the reaction rate of virtually all reactions decreases with decreasing temperature. For example, refrigeration retards the rate of growth of bacteria in foods by decreasing the reaction rates of biochemical reactions that enable bacteria to reproduce.

In systems where more than one reaction is possible, the same reactants can produce different products under different reaction conditions. When two reactants are in the same fluid phase, their particles collide more frequently than when one or both reactants are solids or when they are in different fluids that do not mix.

If the reactants are uniformly dispersed in a single homogeneous solution, then the number of collisions per unit time depends on concentration and temperature, as we have just seen. If the reaction is heterogeneous, however, the reactants are in two different phases, and collisions between the reactants can occur only at interfaces between phases. The number of collisions between reactants per unit time is substantially reduced relative to the homogeneous case, and, hence, so is the reaction rate.

The reaction rate of a heterogeneous reaction depends on the surface area of the more condensed phase. Automobile engines use surface area effects to increase reaction rates. More collisions afford more opportunities for reaction. How do catalysts affect the rate of a reaction? Catalysts speed up chemical reactions. Only very minute quantities of the catalyst are required to produce a dramatic change in the rate of the reaction.

This is really because the reaction proceeds by a different pathway when the catalyst is present essentially lowering the activation energy required for the reaction to take place. How does concentration affect the rate of a reaction? Increasing the concentration of the reactants will increase the frequency of collisions between the two reactants. When collisions occur, they do not always result in a reaction atoms misaligned or insufficient energy, etc.

Higher concentrations mean more collisions and more opportunities for reaction. What affect does pressure have on the reaction between two gasses? You should already know that the atoms or molecules in a gas are very spread out. For the two chemicals to react, there must be collisions between their molecules. By increasing the pressure, you squeeze the molecules together so you will increase the frequency of collisions between them.

You can easily increase the pressure by simply reducing the volume of the reaction vessel the gases are in. How does surface area affect a chemical reaction? If one of the reactants is a solid, the surface area of the solid will affect how fast the reaction goes. This is because the two types of molecule can only bump into each other at the liquid solid interface, i.

So the larger the surface area of the solid, the faster the reaction will be. But you can increase the surface area of a solid by cutting it up. Think of it this way, if you have a loaf of bread you have 6 sides of surface area, correct?

When the pressure of a gaseous equilibrium system is increased, the yield of the side with the fewest moles will increase this is again due to Le Chatalier's principle As a result, there will be some situations in which increasing the temperature and pressure will increase the rate of reaction, but decrease the overall yield of product ie.

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