a highly toxic gas called phosgene is produced by the reaction CO(g)+Cl2(g)-->COCl2(g), triangleH=-108 kJ/mol.
how would increasing the temperature affect the amount of COCl2 formed? Explain.
how would increasing the temperature affect the rate of the reaction? Explain
CO(g)+Cl2(g)-->COCl2(g), delta H = -108 kJ/mol.
A negative delta H means the reaction is exothermic so let me rewrite the equation as CO(g) + Cl2(g) --> COCl2(g) + heat
This question is one about Le Chatelier's Principle. Le Chatelier's Principle states that "when a system in equilibrium is subjected to a stress, the reaction will shift is such a way as to relieve the stress". Many students just don't understand that. A shorter and much less esoteric (but just as accurate) statement is "A system at equilibrium will undo what we do to it". Therefore, if we INCREASE the temperature (ADD HEAT), the system will react to REMOVE the heat. How can it do that. It COULD move to the right which will produce more COCl2 and more heat. That isn't what you want. OR it COULD move to the left. If it does that COCl2 + heat produces more of the CO and Cl2. That way the system is using up the heat we've added. That's what it does. So the correct answer is that the reaction will shift to the left using up COCl2 (along with some of the added heat) and producing more of the starting materials of CO and Cl2.
As for the second question, increasing T increases the mobility of the reactants so they interact more frequently which increases the rate of the reaction.
Increasing the temperature would increase the amount of COCl2 formed in the reaction. This is due to the fact that the reaction is exothermic, as indicated by the negative value of the enthalpy change (ΔH = -108 kJ/mol). According to Le Chatelier's principle, an increase in temperature will favor the endothermic direction to counteract the increase in energy. In this case, it means that the equilibrium will shift towards the right to produce more COCl2, thereby increasing its amount.
On the other hand, increasing the temperature would also increase the rate of the reaction. According to the Arrhenius equation, the rate of a chemical reaction is directly proportional to the temperature. This is because an increase in temperature provides more energy to the reactant molecules, causing them to collide with greater force and frequency. Consequently, this leads to more successful collisions and a higher rate of reaction.
To understand how increasing the temperature would affect the amount of COCl2 formed and the reaction rate, we need to consider the principles of Le Chatelier's principle and the effect of temperature on reaction equilibrium.
1. Effect on the Amount of COCl2 Formed:
According to Le Chatelier's principle, when a system experiences a change, it tends to counteract that change and restore equilibrium. In this case, increasing the temperature will cause the reaction to shift in the direction that absorbs or consumes heat, which is the reverse reaction in this case.
The forward reaction (CO(g) + Cl2(g) → COCl2(g)) is exothermic, meaning it releases heat, while the reverse reaction (COCl2(g) → CO(g) + Cl2(g)) is endothermic, requiring the absorption of heat. Therefore, increasing the temperature of the reaction mixture will favor the reverse reaction.
As a result, according to Le Chatelier's principle, increasing the temperature would decrease the amount of COCl2 formed. This is because the system tries to reduce the temperature increase by shifting the equilibrium towards the reactants (COCl2 → CO + Cl2).
2. Effect on the Rate of the Reaction:
An increase in temperature generally increases the rate of a chemical reaction. This is due to the impact of temperature on the kinetic energy of the particles involved.
As the temperature increases, the kinetic energy of the molecules also increases. This leads to higher molecular collisions and more effective collisions between the reactant molecules. Consequently, the frequency of successful collisions and the number of molecules with sufficient energy to overcome the activation energy barrier increases, resulting in a higher reaction rate.
Therefore, increasing the temperature would accelerate the rate of the CO(g) + Cl2(g) → COCl2(g) reaction, provided that other factors, such as reactant concentrations and catalysts, remain constant.
In summary, increasing the temperature would decrease the amount of COCl2 formed by shifting the reaction equilibrium towards the reactants, following Le Chatelier's principle. However, it would simultaneously increase the rate of the reaction due to the enhanced kinetic energy and increased collision frequency of the reactant molecules.