In this step, you'll create an energy graph to illustrate the energy change during the combustion of propane. Here's how to do it:
1. Understand the Energy Graph Components
X-axis (Reaction Progress): This axis represents the progress of the reaction from reactants to products.
Y-axis (Energy): This axis represents the energy (in kJ).
2. Plotting the Points
Identify Key Points:
Start (Reactants): The energy level of the reactants (C₃H₈ and O₂) is at –103.85 kJ/mol.
Transition State (Peak): This is the highest energy point, which occurs at the transition state of the reaction. You can estimate this value, but it is typically higher than the energy of the reactants.
End (Products): The energy level of the products (CO₂ and H₂O) is at –2147.81 kJ/mol.
3. Draw the Graph
Label the Axes:
X-axis: "Reaction Progress"
Y-axis: "Energy (kJ)"
Plot the Reactants: Start at –103.85 kJ on the Y-axis.
Draw the Transition State: Increase the energy to a peak (you'll estimate this value; it could be around –80 to 0 kJ for demonstration).
Plot the Products: Draw a line down to –2147.81 kJ.
Connect the Points:
Draw a line from the reactants to the transition state (upward curve) and from the transition state down to the products (downward curve).
Label the Points:
Mark the reactants, transition state, and products on the graph.
4. Add Titles and Annotations
Title: "Energy Change During the Combustion of Propane"
Annotations: You can add notes about whether the reaction is exothermic (indicated by the drop in energy) and the significance of the energy change.
Example Structure of the Graph:
Reactants: Starts at –103.85 kJ
Transition State: Peaks at an estimated higher energy point
Products: Ends at –2147.81 kJ
Mark
The student created a model of the energy change in the reaction. The model is an energy graph that clearly
shows the change in energy for the chemical reaction. The axes are labeled, a title is provided, and the reactants
and products are identified on the graph.
label all the important points on the graph with a little name