Thermochemistry Flashcards
Thermochemistry
Study of measuring the amount of heat absorbed or released during a chemical reaction or a physical change
Energy
Capacity to supply heat or do work
Work (w)
Energy transfer due to changes in external, macroscopic variables such as pressure and volume; or causing matter to move against an opposing force
Potential Energy
Energy of a particle or system of particles derived from relative position
Kinetic Energy
Energy of a moving body, in joules, equal to 1/2mv^2 (where m = mass and v = velocity)
Thermal Energy
Kinetic energy associated with the random motion of atoms and molecules
Temperature
Intensive property of matter that is in a quantitative measure of “hotness” and “coldness”
Heat (q)
Transfer of thermal energy between two bodies
Exothermic Process
Chemical reaction or physical change that releases heat
Endothermic Process
Chemical reaction or physical change that absorbs heat
Calories (cal)
Unit of heat or other energy; the amount of energy required to raise 1 gram of water by 1 degree Celsius; 1 cal is defined as 4.184 J
Joule (J)
SI unit of energy; 1 joule is the kinetic energy of an object with a mass of 2 kilograms moving with a velocity of 1 meter per second, 1 J = 1 kg m^2/s and 4.184 J = 1 cal
Heat Capacity
Extensive property of a body of matter that represents the quantity of heat required to increase its temperature by 1 degree Celsius (or 1 kelvin)
Specific Heat Capacity (c)
Intensive property of a substance that represents the quantity of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius (or 1 kelvin)
Calorimetry
Process of measuring the amount of heat involved in a chemical or physical process
System
Portion of matter undergoing a chemical or physical change being studied
Surroundings
All matter other than the system being studied
Calorimeter
Device used to measure the amount of heat absorbed or released in a chemical or physical process
Bomb Calorimeter
Device designed to measure the energy change for processes occurring under conditions of constant volume; commonly used for reactions involving solid and gaseous reactants or products
Nutritional Calorie (Calorie)
Unit used for quantifying energy provided by digestion of foods, defined as 1000 cal or 1 kcal
Chemical Thermodynamics
Area of science that deals with the relationships between heat, work, and all forms of energy associated with chemical and physical processes
Internal Energy (U)
Total of all possible kinds of energy present in a substance or substances
First Law of Thermodynamics
Internal energy of a system changes due to heat flow in or out of the system or work done on or by the system
Expansion Work (Pressure-Volume Work)
Work done as a system expands or contracts against external pressure
