Chemical Reactions, Environmental Impact, and Ecosystem Health

Key Chemical Equations

N₂ + 3 O₂ → 2 N₂O₃

Cu + 2 HCl → CuCl₂ + H₂

2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

2 Al + 6 H₂O → 2 Al(OH)₃ + 3 H₂

Understanding Environmental Impact

Environmental impact is the set of negative effects on the environment resulting in a modification of the natural surroundings. Depending on the medium it affects, impacts are classified as:

• Impacts on the atmosphere: Produced by solid-phase particles and emissions into the atmosphere.
• Impacts on the hydrosphere: Produced by the introduction of all sorts of substances into the hydrosphere.
• Impacts on the soil: Caused by erosion or the discharge of different substances onto the ground.
• Impacts on the biosphere: Caused by the degradation of ecosystems.

The Problem of Acid Rain

Acid rain is a form of pollution that builds up in the clouds and occurs with the precipitation of harmful chemicals. Most of these substances come from factories, industries, and also vehicle emissions. It causes damage to buildings and works of art and can destroy forests, rivers, and lakes, harming fish and trees.

Water Contamination and Runoff

Runoff can be contaminated in two ways: from natural sources or by human action.

• Natural Sources: Pollen, plant residues, and animal residues.
• Human-Caused Sources:
  • Urban water containing detergents.
  • Agricultural water containing fertilizers and pesticides.
  • Water from livestock sources.
  • Water from factories that contain chemical spills.
  • Thermal pollution from the discharges of nuclear power plants.

In the case of aquifers, they can be contaminated by permanent or temporary saltwater intrusion. The waters in the seas are polluted mainly by oil spills and leaks.

The Causes of Species Extinction

The main cause of species extinction is the destruction of natural habitats (e.g., clearing land for farming, logging). Another cause is the contamination of water and the atmosphere. Furthermore, hunting and the fashion of having exotic animals contribute to their extinction.

A Look at Medicines

A medicine, or drug, is any substance or preparation that has healing properties and is administered to humans or animals to help them recover from illness. It is composed of an active drug substance and excipients. Its origin can be:

• Plant-based
• Animal-based (e.g., hormones)
• Mineral-based (e.g., aluminum hydroxide and ferrous sulfate)
• Microbial (from cell cultures)
• Synthetic (created by chemical reactions in a laboratory)

Exothermic and Endothermic Reactions

Exothermic reactions are those in which the internal energy of the reactants is greater than that of the products, so this energy is released in the form of heat, light, etc. The energy released is expressed in calories or joules, preceded by a positive sign (+).

Endothermic reactions, unlike exothermic ones, absorb energy from the outside, often in the form of heat or light. The absorbed energy is expressed in calories or joules, preceded by a negative symbol (-).

Quiz Answers

True or False: V - V - V - F