Chemistry of Water and Carbon

Study Notes

Water is composed of two hydrogen atoms and one oxygen atom linked by a single covalent bond, forming a molecule with a bond angle of 104.5°.
The molecule acts as an electric dipole, with δ+ and δ- charges on the hydrogen and oxygen atoms, respectively.
Water molecules form hydrogen bonds (H-bonds) with themselves and other molecules, which are weaker and longer than covalent bonds but are one of the strongest intermolecular forces.

Water is a liquid at ambient temperature, binding 3.4 other water molecules.
At freezing temperature, water is ice, binding 4 other water molecules, and forms an insulating blanket.
Water has a high melting point, high boiling point, high specific heat capacity, and high heat of vaporization.
Water's high specific heat capacity allows it to absorb and release heat energy without a large change in temperature.

Water's liquid state over a wide temperature range allows for chemical reactions, circulation, and exploitation by microorganisms.
Water's excellent solvent properties enable chemical reactions, waste removal, and delivery of food materials.
Water's ionizing solvent properties are important for nerves and other excitable tissues.
Water's low viscosity is important for circulatory systems.
Water's high surface tension tends to make lung alveoli collapse.
Water's high heat of vaporization is used by mammals for sweating.

Carbon is the central atom of life, containing 4 electrons in its outer shell.
Carbon forms part of essential macromolecules, including pyrimidine, purine, glucose, amino acids, and fat.
The molecular shape of carbon-containing molecules is important for their function, as structure dictates function.

Important physiological buffers include the hypothalamus, renal function, and ionization of pure water into positively and negatively charged ions.
Pure water is pH neutral, with an ionization reaction of H2O ⇌ H+ + OH-.

The ionization of pure water results in the formation of positively and negatively charged ions, with a concentration of hydrogen ions determined by the equation n = mm/MM = 1000 g = 55.5 moles.