Chemical Reactions and Environmental Impact: Key Concepts

Chemical Reactions

A chemical reaction is a process in which one or more substances react to form other substances with different properties.

Chemical Reactions and Chemical Equations

The chemical equation is the symbolic representation of a chemical reaction.

Activation Energy

For a chemical reaction to be possible, particles must collide with a minimum energy.

Reaction Energy

The energy exchange that occurs in the course of a chemical reaction is called the energy of reaction.

Speed of Reaction

The speed at which a chemical reaction takes place.

Factors Influencing the Reaction Rate

• Nature of Reagents: Generally, covalent substances lead to slow reactions at room temperature, while ionic substances react quickly when dissolved.
• Temperature: The reaction rate increases with temperature elevation.
• Degree of Division of Reagents: To facilitate the effective collisions needed, maximize the contact between the reactants.
• Concentration: Increasing the concentration increases the number of effective collisions.
• Catalyst: A substance that decreases the activation energy and thus affects the rate of reaction.

Pollution and Environmental Impact

Pollution is the presence in the environment of any agent or pollutant that causes negative environmental consequences. Environmental impact refers to all possible negative effects on the environment. As they affect the environment, we can refer to:

• Impacts on the Atmosphere: Produced by gaseous and solid emissions.
• Impacts on the Hydrosphere: Produced by the dumping of all kinds of substances into the hydrosphere.
• Impacts on the Soil: Produced by erosion or the discharge of various substances on the surface.
• Impacts on the Biosphere: Due to the degradation of ecosystems, loss of species diversity, extinction, and so on.

Ozone Depletion

Ozone is a bluish gas composed of 3 oxygen atoms, O₃, found in the stratosphere at a height of 20 to 30 km. Its role is to absorb most of the ultraviolet rays emitted by the sun, which are very harmful to health. Ozone is created and destroyed at the same speed, so the total amount in the atmosphere remains constant. As the ozone layer protects us from radiation from space, its depletion causes skin and ocular diseases, etc.