energy

# energy - • 1st law of thermodynamics energy is conserved...

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energy  - ability to do work or transfer heat   force - any type of push/pull placed on an object work - energy used to make an object move against a force o work = force x distance heat - energy transferred from hotter object to colder one kinetic energy - energy of motion o Ek = 1/2 mv2 o thermal energy - from kinetic energy of molecules in a substance potential energy - energy based on relative position o Ep = mhg, where g = 9.8 m/s2 (gravitational constant) o chemical energy - from potential energy in bonds electrostatic energy - interactions w/ charged particles; form of potential energy o Eel = (kQ1Q2) / d o positive when 2 charges repel each other, negative when attracting each other joule - SI unit for energy calorie - amount of energy required to raise temperature of 1g of water by 1° o 1 calorie = 4.184 joules o 1 Cal = 1 nutritional calorie = 1000 calories = 1 kcal internal energy  - sum of all kinetic/potential energy in a system
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Unformatted text preview: • 1st law of thermodynamics- energy is conserved, moves between system/surroundings • numerical value of E can't be found, only change in E (DE) • DE = Efinal - Einitial • DE negative when energy lost (exothermic) • DE positive when energy gained (endothermic) • DE = q + w o q positive when heat moves from surroundings into system, negative when heat moves from system into surroundings o w positive when surroundings work on system, negative when system works on surroundings system - area isolated for study • surroundings- everything other than the system in question • closed system - can exchange energy but not matter w/ surroundings state function - property of system determined by its condition/state • doesn't depend on how a change is carried out • examples of state functions - E, DE • not examples of state functions - work, heat...
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