CP Biology

 What does it mean to say water is polar?  How does water’s polarity help it with hydrogen bonding?  How does hydrogen bonding cause ice to be less dense than water?

 Water has multiple hydrogen bonds so it takes a lot of heat to cause those molecules to move faster (raising the temperature).  Water’s heat capacity is high.  Large bodies of water can absorb a lot of heat with only small changes in temperature.  Is the weather more constant in Hawaii or New Mexico?

 A mixture is a material composed of two or more elements or compounds that are physically mixed but not chemically combined. Images from bright hub education

GBJ.com Air Blood Ocean water

 Mixtures are categorized into 1) solutions and 2) suspensions.  All components of a solution are evenly distributed throughout a solution.  Solute: the substance that is dissolved  Solvent: the substance in which the solute dissolves example: water and salt

 Water’s polarity allows it to dissolve both ionic compounds and polar molecules.  When water has dissolved as much as it can hold, it is called saturated. Image from Pearson Image from SUNY

 Some materials do not dissolve and settle into small particles  The movement of water keeps them suspended  Suspensions are mixtures of water and undissolved material

 Water molecules often split apart to form ions.  The pH scale is a measurement systems that indicates the concentration of H+ ions in solution.  pH of 7 is neutral because the concentration of H+ and OH- is equal  The lower the pH, the more acidic  The higher the pH, the more basic.

 Solutions with a pH below 7 are called acidic because they have more H+ ions than OH- ions.  Solutions with a pH above 7 are called basic because they have more OH- ions than H+ ions.  Each step on the pH scale represents a factor of 10. A liter of solution with a pH of 4 has 10 times as many H+ ions as a liter of solution with a pH of 5.

Image from Pearson