Im doing a worksheet and i had to draw PE diagram which had the Ea(activation energy)at 80kJ and the enthalpy change is -40kJ.
*All the reactants and products are gases
Then it asks to describe what would happen to the diagram if the temperature dropped 25 degrees Celsius. Im not sure what the next thing i need to do is exactly and if i need to do other calculations.
If you could help me understand what its asking me to do
To understand what would happen to the PE (potential energy) diagram if the temperature dropped by 25 degrees Celsius, you need to consider the effect of temperature on the reaction. Temperature influences the kinetic energy of molecules, which in turn affects the reaction rate.
In this case, since the reactants and products are gases, we can infer that the reaction involves gaseous molecules colliding and reacting. Generally, as temperature increases, the kinetic energy of the molecules also increases. This leads to more frequent and energetic collisions, resulting in a higher reaction rate.
Now, let's apply this knowledge to the question. The given information specifies the activation energy (Ea) as 80 kJ and the enthalpy change (ΔH) as -40 kJ. The enthalpy change represents the overall energy difference between the reactants and products in a chemical reaction.
When temperature drops, the average kinetic energy of the molecules decreases. This means that fewer molecules possess the necessary energy to overcome the activation energy barrier. As a result, the reaction rate decreases. In terms of the PE diagram, the height of the energy barrier (Ea) is mainly determined by the activation energy.
To answer the question more specifically, here's what you can do:
1. Understand the current PE diagram: Draw the PE diagram using the given information. Make sure to label the reactants and products, and indicate the energy changes. The activation energy (Ea) should be at 80 kJ, and the enthalpy change (ΔH) should be at -40 kJ.
2. Visualize the effect of temperature drop: Imagine the PE diagram you have drawn and picture it with a lower energy scale. This represents the decrease in temperature.
- Specifically, think about how the activation energy (Ea) might change.
- Consider that a decrease in temperature reduces the kinetic energy of the molecules, impacting the number of collisions capable of overcoming the activation energy.
3. Redraw or modify the PE diagram: Based on your visualization, modify the PE diagram to reflect the effect of the temperature drop. You can do this by decreasing the height of the activation energy barrier (Ea).
- The exact amount depends on the specifics of the question and whether the decrease in temperature is proportional or absolute.
Note: The question does not explicitly state if other calculations are required. However, for a more comprehensive understanding, you can calculate the new activation energy by applying relevant principles such as the Arrhenius equation, which connects the rate constant and temperature to the activation energy.
Remember, the accuracy of the response may vary depending on the specific context and instructions provided in your worksheet.