Basic Chemistry and The Properties Of Water

Elements and Compounds Matter is made up of elements An element is a substance that cannot be broken down to other substances by chemical reactions A compound is a substance consisting of two or more elements in a fixed ratio A compound has characteristics different from those of its elements © 2011 Pearson Education, Inc.

Table 2.1

Figure 2.5 Cloud of negative charge (2 electrons) Electrons Nucleus (a)(b)

Figure 2.8 A ball bouncing down a flight of stairs provides an analogy for energy levels of electrons. Third shell (highest energy level in this model) Second shell (higher energy level) First shell (lowest energy level) Atomic nucleus Energy absorbed Energy lost (b) (a)

Figure 2.12a (a) Hydrogen (H 2 ) Name and Molecular Formula Electron Distribution Diagram Lewis Dot Structure and Structural Formula Space- Filling Model

Figure 2.12b (b) Oxygen (O 2 ) Name and Molecular Formula Electron Distribution Diagram Lewis Dot Structure and Structural Formula Space- Filling Model

Figure 2.12c Name and Molecular Formula Electron Distribution Diagram Lewis Dot Structure and Structural Formula Space- Filling Model (c) Water (H 2 O)

Figure 2.12d (d) Methane (CH 4 ) Name and Molecular Formula Electron Distribution Diagram Lewis Dot Structure and Structural Formula Space- Filling Model

Figure 2.13 H H H2OH2O ++ ++ –– O

Figure – Na Sodium atom Cl Chlorine atom Na + Sodium ion (a cation) Cl – Chloride ion (an anion) Sodium chloride (NaCl)

Figure 2.15 Na + Cl –

Figure 2.16 Water (H 2 O) Ammonia (NH 3 ) Hydrogen bond –– –– ++ ++ ++ ++ ++

Figure 2.18 Natural endorphin Morphine Carbon Hydrogen Nitrogen Sulfur Oxygen (a) Structures of endorphin and morphine (b) Binding to endorphin receptors Brain cell Morphine Natural endorphin Endorphin receptors

Properties of Water

Figure 3.3 Adhesion Two types of water-conducting cells Cohesion 300  m Direction of water movement

Movement of Water Up Xylem Vessels Cohesion – strong attraction of water molecules to each other Adhesion – strong attraction of water molecules to walls of xylem

Figure 3.4

Figure 3.7 Cl  Na                    

Figure 3.8    +  +  

Figure 3.6 Hydrogen bond Ice: Hydrogen bonds are stable Liquid water: Hydrogen bonds break and re-form

Figure 3.UN02 2 H 2 O Hydroxide ion (OH  ) Hydronium ion (H 3 O + ) + 

Figure 3.UN05 Acidic [H + ] > [OH  ] Neutral [H + ] = [OH  ] Basic [H + ] < [OH  ] Bases donate OH  or accept H + in aqueous solutions 14 7 Acids donate H + in aqueous solutions. 0