Properties of Water

Properties of Water What is the chemical formula for water? 2 Hydrogen atoms and 1 Oxygen atom – H2O

Water The most important molecule to living things. Why?

Water is a polar molecule This results in a water molecule with a negative end and a positive end.

Because water is polar it dissolves many substances. Water is considered the Universal Solvent, meaning it can dissolve any polar substance.

Solubility Review Solubility - the measure of how much solute can be dissolved by a solvent at a given temperature. Example: Sugar dissolving in water. Remember, the sugar dissolves faster in hot water than in cold water. As the temperature increases, the solubility increases.

Because water is polar it has these properties: Cohesion- water molecules stick together Surface tension- inward pull of surface water molecules creating a smooth sheet http://www.youtube.com/watch?v=45yabrnry Xk

Because water is polar it has these properties: Adhesion - water molecules stick to other molecules Capillary action - allows water to move UP and through materials

Specific Heat Specific Heat - The amount of heat needed to increase the temperature by 1 degree Celsius. Water has a HIGH Specific Heat! It takes A LOT OF HEAT to raise the temperature of water.

Specific Heat Example It’s a hot day! The sidewalk is hot, the sandy beach is hot. So, you decide to go to the beach. When you jump in the ocean, the water is surprisingly cool! Why??? Because it takes more heat to warm the water then the sidewalk, beach and air!

Water’s Specific Heat Why does water have a HIGH specific heat? It’s POLAR!!! (Of course!) The molecules are SO attracted to each other that it takes A LOT of heat to break the molecules apart.

Density If you look at this picture you can see that some of the iceberg is below the water level. This is due to ice's density being less than liquid water's density. Upon freezing, the density of ice decreases by about 9 percent. Density of water is 1 g/cm³

hydrogen bonds https://www.youtube.com/watch?v=aH2IbYs_XjY Each water molecule is made up of two hydrogen (H) atoms and one oxygen(O) atom. The bonds between water molecules are called hydrogen bonds. when water molecules are close together, their positive and negative regions are attracted to the oppositely-charged regions of nearby molecules. The force of attraction, shown here as a dotted line, is called a hydrogen bond. Each water molecule is hydrogen bonded to four others. https://www.youtube.com/watch?v=aH2IbYs_XjY