# Chemistry 17.1 - 17.4

Topics: Energy, Thermodynamics, Heat Pages: 3 (439 words) Published: May 27, 2013
17.1-17.4 Notes
Energy Transformation
Thermo Chemestry
Study of energy changes that occur during chemical reactions and changes in state Chemical Potential Energy
energy stored in Chemical bonds
Heat
energy that transfers from one object to another because of a temperature difference between them
Heat always flows from a warmer object to a cooler object
Exothermic and Endothermic Processes
System
part of the universe you focus all of your attention to
Surroundings
everything else in univese
Law of Conservation of energy
states that in any chemical or physical proccess, energy is neither created or destroyed Endothermic
one that absorbs heat from the surroundings
in a endothermic process the system gains heat as the surroundings cool down Exothermic
one that releases heat to its surroundings
in exothermic process, system gains heat as surroundings cool down units for measuring heat flow
heat flow is measured in 2 common units, Calorie and Joule
1 Calorie = 1 kiloCalorie = 1000 calories
Heat Capacity and Specific Heat
the heat capacity of an object depends on both its mass and its chemical composition C = q/m x T = heat/mass(g) x change in temperature(C)
Calorimetry
precise measurement of the heat flow into or out of a system for chemical and physical process in calorimetry, the heat released by the system is equal to the heat absorbed by its surrounding. Conversely, the heat absorbed by a system is equal to the heat released by its surroundings calorimeter

Enthalpy
heat content of a sytem
Thermochemical Equations
enthalpy change for the reactions can be written as either a reactant or as a product

Questions

38. energy is neither created nor destroyed.
39. heat flows from hot to cold. Touching a cold metal chain 40. Potential energy energy stored in the bonds of a substance 41. depends on mass and chem composition
42 A Calorie is 1000 calories.
43. a) .85 calories
b) 106.12 joules
c) 1800 joules...