UNIT 4 LESSON 5 – ENERGY CHANGES

Exothermic Reaction

A reaction that transfers energy to the surroundings, leading to an increase in the temperature of the surroundings.

Endothermic Reaction

A reaction that takes in energy from the surroundings, resulting in a decrease in the temperature of the surroundings.

Activation Energy

The minimum amount of energy that particles must have to react, allowing chemical reactions to occur.

Reaction Profiles

Graphical representations displaying the relative energies of reactants and products, along with activation energy and total energy change of a reaction.

Energy Change of Reactions

Energy is supplied to break bonds in the reactants and released when bonds in the products are formed, with the overall energy change calculated from bond energies.

Fuel Cell

A device generating electricity by converting fuel and oxygen into electricity, heat, and water through a chemical reaction.

Anode

The negative electrode where hydrogen is fed into a fuel cell.

Cathode

The positive electrode where oxygen is fed into a fuel cell.

Non-rechargeable Cells & Batteries:

Cells where chemical reactions stop when one of the reactants has been used up

Rechargeable Cells & Batteries

Cells that can be recharged by reversing reactions when an external electrical current is supplied.

Hydrogen Fuel Cell

A type of fuel cell using hydrogen and oxygen to produce an electrical current, with hydrogen stored at high pressure.