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Energy and Reactions. Honors Biology. Energy. Energy – ability to do work or cause a change Kinetic Energy energy of motion Ex: Heat, moving ball Potential Energy stored energy as a result of position or location Ex: Sitting ball ATP – adenosine tri phosphate
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Energy and Reactions Honors Biology
Energy • Energy– ability to do work or cause a change • Kinetic Energy energy of motion • Ex: Heat, moving ball • Potential Energy stored energy as a result of position or location • Ex: Sitting ball • ATP– adenosine triphosphate • Unit of energy cells use • 3 phosphates; 3rd P has high energy bond
ATP Adenine Triphosphate Ribose
Chemical Reactions • Bonds between atoms are made or broken and the substances change into something else • Represented by chemical equations • Ex: Methane burning in air CH4 + 2O2→ CO2 + 2H2O (reactants) (products) • Equation must be balanced (coefficient vs. subscript)… PRACTICE!!! • Atoms are never created or destroyed, only change form
PRACTICE PROBLEMS 1) ____ H2 + ____ O2____ H2O 2) __ AlBr3 + __ Cl2__ AlCl3 + Br2 **3) __Ca(OH)2 + __H3PO4 __ Ca3(PO4)2 + __H2O
Answers WRONG: 4AlBr3 + 6 Cl24AlCl3 + 6 Br2 2 AlBr3 + 3 Cl22 AlCl3 + 3 Br2
Answers 1) 2 H2 + 1 O2 2 H2O 2) 2 AlBr3 + 3 Cl22 AlCl3 + 3 Br2 **3) 3 Ca(OH)2 + 2 H3PO4 1 Ca3(PO4)2 + 6 H2O
Endergonic Reactions– absorbs energy • Energy absorbed from surroundings and stored in bonds • Ex: Photosynthesis • Products have more ENERGY than reactants • Exergonic Reactions– releases energy • Releases ENERGY to environment • Ex: Cellular Respiration • Reactants have more ENERGY than products • Energy Coupling– Energy released from exergonic rxns powers endergonic ones
Real Life Examples… • Exergonic (Exothermic) • Cellular Respiration • Energy (ATP) is released when glucose is broken down • Endergonic (Endothermic) • Photosynthesis • Energy (ATP) is NEEDED (consumed) to put together glucose from CO2, H20 and sunlight