Thermochemsitry Flashcards
(26 cards)
Work
Energy used to cause an object to move
Heat
Energy used to increase an objects temperature
System
Part of the universe we are looking at
Surroundings
Everything else
State function
Property of a system that only depends on the systems initial and final state
(Final - initial)
Heat (j) joule
Unit of energy 1J=1kg-msquared over s squared
Delta t (tfinal - tinitial) is a
State function
Q=mcdeltat
If q>0 the reaction is
Endothermic
Q=mcdeltat
If q
Exothermic
First law of of thermodynamics
Energy is conserved
Energy can be ____ or _______
Heat or work
Change in energy =
Heat + work
Enthalpy (h)
The heat content and flow of a system due to chemical changes
The change in enthalpy that accompanies a chemical reaction is known as
Enthalpy of reaction or
Heat of reaction
Delta h rxn
Calorimetry is
The measure of heat flow q=mcdeltat
Q=mcdeltat
M= mass(grams)
C=specific heat capacity (j/g x degrees Celsius)
Delta t= change in temperature
Specific heat capacity
The amount of heat required to raise 1g of substance 1degree c
(J/g degree Celsius)
Molar heat capacity
The amount of heat required to raise 1 mol of substance 1 degree celsius (j/mols degree Celsius )
Heat capacity
Amount of heat required to raise an amount of substance 1 degree Celsius (j/degree Celsius)
Hess’s law (of heat summation)
If a reaction occurs in steps, delta h is equal to the sum of the steps
Standard enthalpy of formation of a compound
Enthalpy for the reaction that forms one mile of the compound from its constituent elements
Work formula
P * delta v
Which reactions are more thermodynamicly favored?
Ectothermic
Enthalpy of reaction =
Sum of heat of products-sum of heat of reactants
