Unit Three Flashcards
How do hot and cold packs work?
Hot packs- chemical reaction that releases energy (exo)
Cold packs- chemical reaction that takes in energy (endo)
What is the x and y axis on a heating and cooling curve
Temp is y
Time/ heat added is x
What is the opposite of sublimation
Deposition
What is the opposite of vaporization
Condensation
What is the opposite of fusion
Solidification
What are the x and y on phase diagrams
X axis is temp
Y axis is pressure
What is the critical point
Temp at which it is impossible to liquefy the substance no matter pressure
What is triple point
Where all three phases are at equilibrium, same temp and pressure
At constant temp what would you do to cause a substance to change from liquid to solid
Increase pressure
If it’s not a phase change, it’s a
Temperature change
Thermochemistry
The study of energy changes associated with chemical reactions
Heat
The transfers of thermal energy between two bodies at different temps
Thermal energy
Energy associated with random movement of atoms of molecules
System
The specific part of the universe that one is studying
Surroundings
The rest of the universe, everything but the system
Universe
The combination of the item under investigation and the immediate factors that can influence it
Universe=
System plus surroundings
Types of systems
Open, closed, isolated
Open system
Allows transfer of both energy and mass
Closed system
Energy can leave but mass can not
Isolated system
Mass not energy transfer can happen ( no such thing)
Enthalpy (H)
Is the total energy of a system, some of which is stored as chemical energy in the chemical bonds
T or F energy absorbed from broken bonds never equal that released in making new bonds
T
Exothermic
Release more energy put in
