18.4: Potential Energy Diagrams
The activation energy is the barrier that must be overcome for the reactants to be able to become products in a potential energy diagram. Figure below shows potential energy diagrams for an endothermic (A) and exothermic reaction.
A potential energy diagram is a diagram that shows the change in potential energy of a system as reactants are converted into products. It is used to describe endothermic and exothermic micromolecular reactions, as well as diagrams of activation energy and reaction progress.
Contributors and Attributions
Sharon Bewick, Richard Parsons, Therese Forsythe, Shonna Robinson, Jean Dupon, and Shona Robinson, as well as members of the Royal Newfoundland and Labrador Air Ambulance Service (RANA), courtesy of the CK-12 Foundation.
How the potential energy diagram is used to identify if the reaction is endothermic or exothermic?
A potential energy diagram, also known as a reaction progress curve, depicts the energy changes that occur during a chemical reaction. Keep in mind that the enthalpy change (H) is positive for an endothermic reaction and negative for an exothermic reaction.
What is enthalpy diagram?
An enthalpy diagram plots information about a chemical reaction, such as the starting energy level, the amount of energy required to activate the reaction, and the ending energy, with the enthalpy on the y-axis and time, or reaction progress, on the x-axis.
Is Melting ice endothermic or exothermic?
Melting ice is an endothermic reaction because the ice absorbs (heat) energy, causing the water molecules to move faster and collide more frequently, causing the temperature of the ice to rise and the ice to turn into water!
Is endothermic hot or cold?
Endothermic reactions are the polar opposite of exothermic reactions in that they absorb heat energy from their surroundings, resulting in a colder environment as a result of the reaction.
How do I calculate enthalpy?
Once you have m, the mass of your reactants, s, the specific heat of your product, and T, the temperature change caused by your reaction, you can use the formula H = m x s x T to solve for the enthalpy of reaction. Your answer will be in the unit of energy Joules (J).
What is energy profile diagram?
An energy profile is a diagram that depicts the energy changes that occur during a chemical reaction. The enthalpy change for the reaction is measured from the energy of the reactants to the energy of the products on an energy profile. Exothermic reactions release energy.
What is reaction profile diagram?
The enthalpy change is calculated from the difference in enthalpy between the enthalpy of the products (Hsub>p/sub>) and the enthalpy of the reactants (Hsub>r/sub>) as a chemical reaction proceeds from reactants to product, referred to as the energy pathway.
What are two examples of exothermic?
The following are some examples of exothermic reactions:
- Making an ice cube is a process in which a liquid changes its state from liquid to solid.
- Snow formation in clouds.
- Burning of a candle.
- Rusting of iron.
- Burning of sugar.
- Formation of ion pairs.