Chapter 2.2
Draw: H2 F2 CO2 CF4 Bell-ringer Practice
Now Draw Water
Polar Covalent Bond Molecules have partial positive and partial negative charges (from unequal sharing of electrons)
Aattraction between slightly positive and slightly negative atom 1. Aattraction between slightly positive and slightly negative atom
Properties of Water High Specific Heat Cohesion-attraction of molecules of a substance Ex. Surface tension---water sticks to water 3. Adhesion-attraction of molecules of a different substance Ex. Water sticks to windshield Properties of Water
pH Scale Acids mix with water and release a Hydrogen ion. Bases take a Hydrogen away , resulting in OH- (Hydroxide) pH Scale
Monday August 30 Draw a water molecule showing hydrogen bonds List 3 properties of water Lemon juice has pH=2—is it acidic or basic? What is the difference in H+ ion concentration b/w lemon juice (pH=2) and tomato juice (pH=4) Monday August 30 Warm-up
2. Lemon Juice is acidic 3. Lemon juice has a H+ concentration 100 times greater than Tomato juice.
Ch. 2 Chemisty of Life 2.4 Chemical Reactions
Bonds break during chemical reactions. Chemical Reactions: process that changes substances into different substances by breaking and forming chemical bonds. EX: carbon dioxide and water vapor you breathe out is made by chemical reactions Bonds break during chemical reactions.
Reactants, Products, & Bond Energy Reactants: substances changed during a chemical reaction Products: substances made by a chemical reaction Example: 6CO2 +C6H12O6 6CO2 + 6H2O Reactants Products Reactants, Products, & Bond Energy
Bond Energy: the amount of energy that will break a bond between two atoms. The same amount of energy is needed to break apart a bond as was used to form the bond.
Chemical Equilibrium Equilibrium = Balance Many reactions move in both directions depending on the concentrations of the reactants/products CO2 + H2O H2CO3 Equilibrium: when both the reactants and products are made at the same rate. Chemical Equilibrium
Energy & Chemical Reactions Activation Energy-the amount of energy that needs to be absorbed for a chemical reaction to start. Ex: pushing a rock up hill (see fig. 2.20) Energy & Chemical Reactions
Endothermic Reaction Absorbs more energy than it releases Total energy released
Releases more energy than it absorbs
Differenc between both… Exothermic Endothermic Chemical reaction releasing more energy than it absorbs (the excess is often given off as heat or light) Bond energy is lower in product Ex. Cellular Respiration Fireflies, Angler Fish, Squid Chemical reaction absorbing more energy than it releases. Bond energy is higher in product Ex: Photosynthesis Differenc between both…