Water Emergent Properties of Water – Water is perhaps the most important Molecule found on the surface of the Earth. It makes up roughly 75% of Earth's surface and between % of the volume of our cells. It is no wonder that the evolutionary tree starts with organisms that resided in it.

Water’s Unique Properties - Polarity – Very polar, bent, & able to form weak chemical bonds (H or dipole) with many other molecules (universal solvent) Cohesion - the ability of water to form and break bonds with itself. (aids in the transport of water in plants) Adhesion - the ability of water to stick to other substances (the walls of a graduated cylinder) High surface tension - inward force that adds to the viscosity of water (allows it to form a droplet)

Water’s Unique Properties – Thermal Conductivity High specific heat - amount of energy required to raise 1g of a substance 1 degree Celsius) High heat of vaporization - amount of heat required to change water from a liquid to a gas. (Due to its ability to form H-bonds) Moderates the temperature of the Earth through the absorption and release of energy. – Exhibits latent heat…releases the heat absorbed slowly over time with only a slight change in its own temperature. – Allows for evaporative cooling as the water molecule leaving a substance takes thermal energy with it.

Water’s Unique Properties – Universal Solvent Water dissembles ionic substances in the process of solvation by forming hydration shells (Sphere of water around an ion. Water is the solvent, the ionic substance is the solute, and the liquid is named an aqueous solution. – *** 1 mole of water weighs 18 grams but that the Molarity (M) is the moles of the solute in 1L (1000ml) – Breaks bonds of macromolecules via the process of hydrolysis – Forms bonds in macromolecules via the process of dehydration synthesis Things that are attracted to water (polar molecules) without dissolving are said to be hydrophilic and those that repel water (non-polar molecules) are said to be hydrophobic. The addition of these molecules forms a colloid.

Water’s Unique Properties – Self Ionization Water constantly dissociates to form the ions H + and OH -. As a result the free proton binds with a free water molecule forming the hydronium ion(H 3 O + ) – The pH of the liquid if it is pure water is 7 and the concentration of both the hydroxide and hydronium ions are 1 x (K w = 1x ) – Acids and Bases Acids…Any substance that donates a proton (H +) in solution is an acid. – Acidic solutions have a pH 1 x – Turns blue litmus red Bases…Any substance that accepts a proton (H +) in solution is an base. – Basic solutions have a pH > 7.0 and a concentration of ions H + < 1 x – Turn red litmus blue