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Energy!. Matter is anything with mass and volume What then is energy? The capacity to do work or increase the temperature of matter Work is the capacity to move matter over a distance against some resistance. As the box moves up, work is done. This requires energy. Units of Energy.
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Energy! • Matter is anything with mass and volume What then is energy? • The capacity to do work or increase the temperature of matter • Work is the capacity to move matter over a distance against some resistance As the box moves up, work is done. This requires energy.
Units of Energy • joule (J) The SI unit • calorie (cal)-- Enough heat to warm one mL of water 1C 1 cal = 4.184 J • Calorie (kcal) 1 kcal = 1000 cal Heating Curve
Forms of Energy • Kinetic Energy Energy of Motion • Moving faster or moving larger objects both require more energy • Radiant Energy Electromagnetic Radiation • Examples include light, UV, radio waves, microwaves, x-rays, infra red (heat) • Potential Energy Stored Energy • Types of potential energy include gravitational, electrical, and chemical
Forms of Potential Energy • Gravitational and electrical are less vital to Chemistry • You must understand chemical potential energy (chemical energy) • Bond breaking takes energy • Bond making releases energy
Energy and reactions • Exothermic • More energy is released than is absorbed • A net release of energy • The reaction typically feels warm to the touch • Endothermic • More energy is absorbed than is released • A net absorption of energy • The reaction typically feels cool to the touch
The Law of conservation of energy • Energy cannot be created or destroyed. • It can only be converted from one type to another. • Examples of converting energy • Photosynthesis-- radiant to chemical (potential) • Gas engine-- chemical (potential) to kinetic (and heat(radiant)) • Electric motor-- electrical (potential) to kinetic