I have read Le Chateliers principle but am having a little trouble explaining the effect of pressure and temperature on the equilibrium yield of methanol (CH3OH). Can anyone also tell me the effect of the increase of temp will have on the rate of the reaction?

Yield of methanol from what? An increase in T will shift the equilibrium to more products for an endothermic reaction, to fewer products for an exothermic reaction.

It is explained really well in OU S103 book 8 really well

When considering the effect of pressure and temperature on the equilibrium yield of methanol (CH3OH) production, we must first understand Le Chatelier's principle. This principle states that when a system at equilibrium is subjected to a change in conditions (such as pressure or temperature), the system will respond by shifting the equilibrium to counteract the change.

Regarding pressure, the yield of methanol depends on the number of gaseous moles involved in the reaction. Methanol production involves the reaction of carbon monoxide (CO) and hydrogen (H2) gases. The reaction is typically carried out at high pressures, which favor the formation of methanol according to the following equation:

CO + 2H2 ⇌ CH3OH

According to Le Chatelier's principle, if the pressure is increased, the system will try to counteract this change by shifting the equilibrium in the direction that reduces the total number of gas moles. In this case, it means that the system will favor the forward reaction (production of methanol) to reduce the pressure. Conversely, if the pressure is decreased, the equilibrium will shift in the reverse direction (formation of CO and H2) to increase the total gas moles.

Regarding temperature, the effect on the yield of methanol depends on whether the reaction is endothermic or exothermic. In an endothermic reaction, heat is absorbed, while in an exothermic reaction, heat is released.

For the production of methanol, the reaction is exothermic, meaning heat is released. As a general rule, an increase in temperature favors the endothermic direction of a reaction. Therefore, increasing the temperature will shift the equilibrium towards the reverse reaction (formation of CO and H2) and consequently reduce the yield of methanol. Conversely, decreasing the temperature will favor the forward reaction (formation of CH3OH) and increase the yield of methanol.

Regarding the rate of the reaction, an increase in temperature generally speeds up the reaction rate. This is because higher temperatures provide more kinetic energy to the reactant molecules, leading to increased collision frequency and more successful collisions, resulting in a faster rate of reaction. Therefore, an increase in temperature will generally increase the rate of methanol production.

For further explanation and in-depth understanding, I recommend referring to the OU S103 book, particularly Book 8, as it provides comprehensive information on this topic.