Test 2 Flashcards
(23 cards)
Joule
Si unit of energy
System
Part of the universe we are looking at
Surroundings
Everything else
Heat
Energy that is transferred from a hotter object to a cooler one
Enthalpy (delta h)
The heat content and flow die to chemical or physical changes
Ex ice breaking = endothermic reaction
Vaporization
Liquid to gas
Dh > 0
Condensation
Gas to liquid
Dh
Fusion
Solid to liquid
Dh > 0
Solidification
Liquid to solid
Dh
Sublimation
Solid to gas
Dh > 0
Deposition
Gas to solid
Dh
Thermochemical equation
Equation that includes hangs in heat
Specific heat capacity
Amount of heat 1.0 grams of a substance can absorb until it’s temperature increases by 1 degree Celsius
Hess law
If a reaction is carried out in a number of steps, dh for the overall reaction is the sum of dh for each individual step
Standard enthalpy heat of formation
Change in enthalpy that happens when 1 mol of a compound is formed from its elements in their standard state
The enthalpy ( heat ) of a reaction [dh rxn]
Difference between the standard heats of formation of all the reactants and products
Dh rxn= dh formation of products - dh formation of reactants
Solubility rules
All nitrates are soluble
Sodium anything is soluble
Potassium is soluble
Endothermic
Heat moves from the surroundings into a system
Enthalpy of vaporization
Energy required to transform a given quantity of substance into a gas
Symbol for energy content of a molecule is
H
Change in heat content
Q
Also dh
Heat capacity
Amount of energy required to raise the temperature of an object
Phase change
A substance going from one physical state to another. Accompanied by a change in heat energy
