Definitions
functions that depend only on the initial and final states of the system
functions that depend on the path taken to reach a reaction
What is the path function
defines the parts being studied such as the substances involved in the reaction or phase change
System
heat (J = heat released) is on the right side (products) of the equation
exothermic
1 calorie = ____J
4.2J
specific form of thermal energy that can leave or enter a system
heat
the measure of average kinetic energy of the particles of a system.
temperature
are everything else happening around the systems or things being studied
What are the surroundings
Absorb energy on the left side (reactants) of the equation
endothermic
2 H2O2(l) → 2 H2O(l) + O2(g) [H2O2(l) = -98.2 kJ H2O (l)= -285.8]
H = -375.4 (exothermic)
the change in heat when one mole is changed in a reaction at standard state
standard heat of reaction
is the change in heat when one mole of a compound is formed at standard state
Standard heat of formation
system has no exchange of heat, work, or matter between the system and its surroundings
isolated system
ΔH= (436 + 158) – (2 X 568) = -542 kJ
exothermic
Calculate the specific heat if a 15.4 g sample absorbs 393 J when it is heated from 0.0/C to 37.6 /C
.679
The standard enthalpy change when a bond is cleaved (measures the strength of a chemical bond)
bond-dissociation energy
The amount of energy present in molecules available to do work
Gibbs free energy
system has an exchange of heat and work but not a exchange of matter between the systems and surroundings
closed
sunlight + 6CO2(g) + H2O(l) = C6H12O6(aq) + 6O2(g)
endothermic
Means change in (final - initial)
Delta
When two bodies are placed into contact, heat flows from the hotter body to the colder body.
Zeroth Law
Energy cannot be created or destroyed.
1st law
system has heat, work, and matter exchanged between the system and surroundings.
open
States the natural universe is always increasing in entropy
2nd law
A gas in a closed container is heated with 10J of energy, causing the lid of the container to rise 2m with 3N of force.
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