Chemistry of Life

Chemistry of LifeChapter 2Warm Up 8/27Draw a Boron atom.Draw a Potassium IonDraw Magnesium Sulfide Ionic BondDraw H2O (covalent bond)Properties of WaterWhen scienctists look for evidence of life on other planets, they search for water. Why is water so important to life?It is the medium in which chemical reactions take place. Water gives cells structure.Polar molecules?Example: Water molecule with slightly positive Hydrogen and slightly negative Oxygen. They are joined by hydrogen bonds

Hydrogen BondsHydrogen Bond-attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or nitrogen. (See drawing)Properties Related to Hydrogen BondsHigh Specific Heat-Hydrogen bonds give water a high specific heat. Water absorbs heat, which helps to regulate cell temperaturesCohesion-this makes water molecules stick together (ex. Water forms a bead)-2 same Adhesion-like tape holding together 2 things.Properties of Water Continued.Many compounds dissolve in water.Important materials like sugars and oxygen cant be transported through organism unless they are dissolved. Solution-a mixture of 2 different substancesSolvent- substance that dissolves another substanceSolute- substance that dissolves in a solvent.

There are 91 elements on the periodic table. 25 exist in living things. We will not go beyond 3rd energy level. 4 holds 32, then 50, then 725Acids, Bases, and pHSome compounds break into ions when they dissolve in water.Acids- compound that releases a proton-H+ ion when it dissolves in water=high H+ concentration =low pH-1-6Bases- compounds that remove H+ ions from a solution=low H+ concentration = high pH=7=14pH- measurement of a solutions acidity or H+ ion concentration