1.Name one type of chemical bond and tell me how it bonds. 2.Drawl an Lewis dot diagram of an atom of Oxygen which has an atomic number of 8 (hint first figure out how many valence electrons it has) 3.Which of the three bonds is the weakest? 4.Which chemical bond is formed when two atoms share electrons? Warm UP

Chemical Reaction – a process that changes one set of chemicals into another. – Involves the breaking and forming of new bonds. Quantity remains the same =  2 If this represented a chemical reaction, then 1=reactants and 2 = product The reactants “react” to form the product.

Synthesis/Anabolic Reaction: when two or more atoms bond to form a more complex structure. Example: fixing worn or damaged tissues requires a build up of smaller molecules coming together to make a larger molecule. A + B AB

Decomposition/catabolic reaction: When a bond holding atoms together breaks and produces a simpler molecule. Example: Is needed for foods to be digested and energy to be released for your body to use. AB A + B

Activation Energy All reactions need energy to occur. Activation Energy Activation Energy – refers to the energy needed to get the reaction started For example, you must apply force when striking a match to get the fire to start.

Activation Energy Notice in the diagram the different energy levels between the reactants and products. Real life Example: photosynthesis – reactants of water and CO2 and energy from the sun (activation energy) creates products of Glucose and O2. Endothermic reactions – requires energy to be absorbed to complete the reaction. Therefore there will be more energy in the products than in the reactants

Activation Energy Notice the different energy levels between the reactants and products. Example: combustion reactions of fuels. Exothermic reaction- Requires energy to be released to complete the reaction. Therefore, there will be less energy in the products than in the reactants.

Catalysts  Catalyst - a substance that lowers a chemical reactions activation energy ◦ In other words, speeds up the reaction. Enzymes  Biological Catalysts are called Enzymes.  They speed up chemical reactions in the cells. However they are not essential, for the reactions can occur on their own

Enzymes The names of enzymes typically end in “-ase” For example: protease splits proteins into its monomers - amino acids. What do you think carbohydrase does? Splits carbohydrates (polysaccarides) into its monomers - monosaccarides. Also used for: protein synthesis, synthesis of RNA and DNA, etc.

Endothermic Reactions ers/abraham/PDF's/Exothermic%20and%20En dothermic%20Reaction%20Lab%202009%20_ with%20data_.pdf