Types of Chemical Reactions Chemical reactions involve the breaking and forming of chemical bonds between atoms, resulting in the rearrangement of atoms to form...
Chemical reactions involve the breaking and forming of chemical bonds between atoms, resulting in the rearrangement of atoms to form different substances. There are various types of chemical reactions, including:
Chemical reactions can be classified as either exothermic or endothermic, based on the temperature changes that occur during the reaction.
In an exothermic reaction, energy is released to the surroundings, resulting in an increase in temperature. Examples include combustion reactions and many neutralization reactions.
In an endothermic reaction, energy is absorbed from the surroundings, resulting in a decrease in temperature. Examples include photosynthesis and the thermal decomposition of some compounds.
The progress of a chemical reaction can be represented by a reaction profile, which shows the energy changes occurring during the reaction. A peak on the profile represents the activation energy, which is the minimum energy required to initiate the reaction and break the bonds in the reactants.
Problem: Identify whether the following reaction is exothermic or endothermic:
2Na(s) + Cl2(g) → 2NaCl(s) + energy
Solution:
Chemical reactions can be harnessed to generate electricity in devices called chemical cells and fuel cells. In these devices, the energy released from chemical reactions is converted into electrical energy.
Fuel cells are an important technology for generating electricity from chemical reactions in an environmentally friendly manner, as they produce water as the only byproduct.