The Chemical Reactions of Life And Energy

Physical vs Chemical Physical changes involve changes of appearance, orientation or state. They include; bending, cutting, breaking, melting or boiling. The substance itself is not changed ( ice is still water, still H 2 O just arranged differently). Chemical changes involve the formation of a new substance(s) called the product(s), from original substance(s) called the reactant(s). Examples of chemical changes are digesting, rotting, corroding and burning.

Sings of a Chemical Reaction precipitate forms from mixing fluids unexpected color change Smoke or gas bubbles form The change is difficult to reverse Energy (heat or light) is absorbed or released without providing a heat or cooling source.

Sort the following Melting ice Cooking and egg Painting a fence Bending metal Burning wood Rusting iron Welding metal

Writing Chemical Reactions Dear Chemical Reaction, I hope this letter finds you well and in good spirits……. First we need to understand the Law of Conservation of Matter. This states matter is neither created nor destroyed during chemical reactions. (nor does it mysteriously appear or disappear). A balanced, complete chemical reaction must have equal numbers of each type of atom on both the reactant side and the product side.

Respiration and Photsynthesis Respiration, Aerobic C 6 H O 2 -> 6CO 2 + 6H 2 O Energy released as chemical bonds in the sugar are broken more energy is released than is absorbed as chemical bonds form in CO 2 and H 2 O Exothermic, or exergonic Photo synthesis 6CO H 2 O -> C 6 H 12 O 6 +6O 2 Energy is absorbed (sunlight) Energy stored in the chemical bonds of sugar Endothermic, or endergonic

Activation Energy The Spark the energy that must be overcome in order for a chemical reaction to occur.chemical reaction Or the minimum energy required to start a chemical reaction “E a Enzymes work by lowering (or raising) the needed activation energy.

Affect of Enzyme Catalyst

Assignment Peruse pages of text Answer concept check ques. 1,2,4 page 80 Answer concept check ques 1,2,4,5 page 86