CHEMISTRY - LONG QUIZ

• Heat

  Energy that is being transferred from one object to another, because of the energy difference between them
• Heat


  The flow of thermal energy from one object to another
• Heat always flows from warmer to cooler
• Heat


  Represented by "q"
• Chemical reactions and changes in physical state involve

  • Release of heat
  • Absorption of heat
• Endothermic reactions


  Release energy in the form of heat, light, or sound. From surroundings to system. Heat is added to the system. The reaction vessel cools. Heat is absorbed. Energy is added to the system. q is positive.
• Exothermic reactions


  Absorb energy from their surroundings. From system to surrounding. Heat is lost from the system. The reaction vessel warms. Heat has evolved. Energy is subtracted from the system. q is negative.
• Thermodynamics


  Deals with the relationships between heat, work, and energy. It describes how thermal energy is converted into and from other forms of energy and how it affects matter.
• System


  The part of the universe on which you focus your attention, in which a change occurs.
• Surroundings


  Everything else in the vicinity; or includes everything else in the universe.
• Boundary


  Things that separate the system from the surroundings.
• Open system


  Both energy and matter can go in and go out the system.
• Closed system


  Only energy can go in and out. Matter cannot go in and out from the system.
• Isolated system


  Both energy and matter cannot go in and out from the system. System is normally wrapped in an insulator therefore heat cannot go in and go out from the system.
• Thermochemistry


  Concerned with the flow of heat from the system to its surroundings, and vice-versa.
• First law of Thermodynamics / Law of Conservation energy

  Energy cannot be created nor destroyed.
• Energy cannot be created or destroyed
• Energy can be exchanged between objects
• Energy can be informed from one form to another (heat, light, sound)
• Internal energy


  Total amount of kinetic and potential energy a system possesses. Internal Energy is a state function.
• State function


  Mathematical function whose result depends only on the initial and final conditions, not on the process used. Properties that are determined by the state of the system, regardless of how that condition was achieved.
• Energy


  A quantity an object can possess and has the capacity to do work
• Heat and work


  Two different ways that an object can exchange energy with other objects, either out of it, or into it.
• Work


  The energy exchanged when something is moved by a force, like when a gas expands or contracts.
• The difference between heat and work lies in how energy is transferred. Heat is the transfer of energy due to a temperature difference, typically between two objects or regions. Work is the transfer of energy that results from a force acting through a distance, causing a displacement.
• Energy


  Anything that has the capacity to do work.
• Work


  A force acting over a distance.
• Energy can be exchanged between objects through collision
• PV work


  Work that is the result of a volume change against an external pressure.
• Calorie


  The quantity of the heat needed to raise the temperature of 1 g of pure 1 *C
• Calorie in heat is written with a lowercase "c", Calorie in Food is written with an Uppercase "C"
• 1 Calorie = 1 kilocalorie = 1000 cal
• 4.184 J = 1 cal
• Extensive property


  Depends on the amount of matter.
• Intensive property


  Does not depend on the amount of matter.
• Heat capacity


  The amount of heat needed to increase the temperature of an object exactly 1 *C. Depends on both the object's mass and its chemical composition.
• Specific heat (specific heat capacity)


  The quantity of heat required to raise the temperature of one gram of substance by 1 *C. Specific Heat Capacity is an intensive property.
• Cwater = 4.184 J/(g*C), Csand = 0.664 J/(g*C)
• The SI unit is Joules (J) named after James Prescott Joule