Kolsyre

Kolsyre, chemically CO2, is a colorless, odorless gas. It is non-flammable and slightly soluble in water. Each molecule consists of one carbon atom double-bonded to two oxygen atoms. In water it forms carbonic acid (H2CO3) to a limited extent, contributing to the acidity of natural waters and to the buffering capacity of the carbon cycle.

Kolsyre occurs naturally in the atmosphere at about 0.04% by volume and is produced by respiration, fermentation, combustion of organic matter, and volcanic activity. It is released during cement production and other industrial processes. The gas cycles between air, oceans, biosphere, and rocks, with the oceans absorbing substantial amounts and forming carbonates.

Uses: Carbonation of beverages and beer; inert shielding gas in welding and some chemical processes; dry ice (CO2) used for cooling and transport; fire suppression systems rely on CO2 to displace oxygen in enclosed spaces.

Environmental and safety aspects: CO2 is a major greenhouse gas. Human activities, especially burning fossil fuels and cement production, have raised atmospheric CO2 concentrations, contributing to climate change and ocean acidification. In high concentrations, CO2 can cause dizziness, headaches, and asphyxiation; it is colorless and odorless, so proper ventilation is essential in confined spaces.