Heat = mass X change in temp X specific heat 1.10 g X 33 o C X 0.90 J/g o C = 297 J g X  T X 0.50 J/g o C = 5275 J 1.25  T = 5275 – divide both sides by 25  T = 211 – add to 20 o C to find new temp (231 o C) g X 25 o C X C = 6.75 x 10 4 J 1.37,500C = 67,500 – divide both sides by 37,500 2.C = 1.8 J/g o C

Heat Calculations 1.500g x 10 o C x 1.0 cal/g C o = 5,000 cal 2.5,000 cal x 4.2 = 21,000 joules 3.50 g x 80 o C x 0.46 J/g C o = 1,840 joules cal = 100g x 5 o C x X = 500X 2.105/500 = X 3.X = 0.21 cal/g o C 5.31,500 J = 750g X T X 4.2 J/g o C = 10 o C = 3150 T, 31500/3150 = 10

Energy Conversions An energy conversion is a change from one form of energy to another. Any form of energy can be converted into any other form of energy. Kinetic energy is converted to potential energy when an object is moved against gravity. Elastic potential energy is another example of potential energy.

Energy Conversions Your body uses the food you eat to convert chemical energy into kinetic energy. Plants convert light energy into chemical energy. Machines can transfer energy and can convert energy into a more useful form

Conservation of Energy Because of friction, some energy is always converted into thermal energy during an energy conversion. Energy is conserved within a closed system. According to the law of conservation of energy, energy cannot be created or destroyed. Perpetual motion is impossible because some of the energy put into a machine is converted into thermal energy because of friction.

Energy Energy is the ability to do work, and work equals the transfer of energy. Energy and work are expressed in units of joules (J). Kinetic energy is energy of motion and depends on speed and mass. Potential energy is energy of position. Gravitational potential energy depends on weight and height.

Energy Mechanical energy is the sum of kinetic energy and potential energy. Thermal energy and sound energy can be considered forms of kinetic energy. Chemical energy, electrical energy, and nuclear energy can be considered forms of potential energy.