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Published byAshlie Burke Modified over 9 years ago
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Everything that is not matter.
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Think of all the ways this word is used… o.0?
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Energy is the capacity to do work. ◦ In chemistry, energy is most commonly used to do the work necessary to change the temperature of a substance. Temperature is a measure of the average kinetic energy of the particles that make up a substance. All matter is made of atoms which are constantly in motion. The higher the temperature of a substance, the more energy its particles have, and the faster they move. What happens when particles of higher energy (higher temperature) bump into particles of lower energy (lower temperature)?
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When two substances have different temperatures, energy flows between them. ◦ We call this energy heat. ◦ Heat ALWAYS flows from hot to cold. The new temperature will be the average of the two original temperatures: T ave = ½(T 1 + T 2 ) Chemistry often involves the transfer of heat. ◦ When a process results in the evolution of heat, it is said to be exothermic. ◦ When a process results in the absorption of heat, it is said to be endothermic.
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How?
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Units of Heat Energy are calories. ◦ Just like units of length are meters. A calorie is the amount of heat energy required to raise 1 g of water by 1°C. ◦ The calorie is a metric unit of measure. ◦ The abbreviation is cal The SI unit of heat energy is the joule. ◦ The abbreviation is J The equivalency statement between joules and calories is: 1cal = 4.184 J exactly ◦ This can be used as a conversion factor between the two units.
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Does all matter hold the same amount of heat?
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The Specific Heat Capacity of a substance is the amount of energy required to raise the temperature of one gram of that substance 1°C. ◦ Specific Heat Capacity is a physical property. ◦ Every substance has its own unique specific heat capacity. Some stuff heats up easily, and has a low value for specific heat capacity, like gold. Some stuff takes a lot of energy to heat up, so it has a high value for specific heat capacity, like water. ◦ Why is it good that the specific heat capacity of water is so high?
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Q = Energy or heat required m = mass of the sample C = specific heat capacity ΔT = the change in temperature ◦ ΔT = T f -T i = final temp – initial temp This equation can be used to find any of the variables above as long as the rest are known.
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