This question is about methanol - AQA - GCSE Chemistry - Question 9 - 2018 - Paper 2

In the balanced reaction, the mole ratio of carbon monoxide (CO) to hydrogen (H₂) is 1:2. Thus, to find the moles of CO needed for 4.0 x 10³ moles of H₂:

ext{Moles of CO} = rac{1}{2} imes 4.0 imes 10^3 = 2.0 imes 10^3 ext{ moles} The correct answer is 2.0 x 10³ moles.

If the temperature is increased above 250 °C, the yield of methanol decreases. This is because the forward reaction is exothermic, and according to Le Chatelier's Principle, raising the temperature shifts the equilibrium position towards the endothermic reaction, which is to the left. Therefore, less methanol is produced.

Using a higher pressure reduces the volume of the gas mixture, leading to a greater number of collisions between reactant particles. Since there are fewer gas moles on the product side (1 mole of CH₃OH compared to 3 moles of reactants), increasing the pressure shifts the equilibrium position towards the right, resulting in a higher yield of methanol. Additionally, increased pressure results in more collisions per unit time, enhancing the reaction rate.

A catalyst increases the rate of reaction by providing an alternative reaction pathway with a lower activation energy. This allows more reactant molecules to collide with enough energy to react, thus speeding up the overall reaction without being consumed in the process.

A catalyst is used in this industrial process to reduce the energy requirements for the reaction. This leads to lower operational costs and makes the process more efficient without focusing on reaction rates.

Using a catalyst has no effect on the equilibrium yield of methanol itself. It only increases the rate at which equilibrium is achieved, allowing the system to reach the equilibrium state faster.