Thermochemistry Flashcards
(17 cards)
Define closed system
Matter cannot be transferred
Heat can be conducted
Define open system
Matter can be transferred
Heat can be conducted
Define isolated system
No matter transferred
No heat conducted (vacume)
Define energy
Capacity to do work or transfer heat
Define 1 calorie
Heat energy required to raise the temperature of 1.00g of H20 by 1 degree
What is the 1st law of thermodynamics in a closed system
(Change in) U = q + w
What is kelvins statement of the 2nd law of thermodynamics?
(delta)G = (delta)H - T(delta)S
State the 1st law of Termodynamics
Energy can neither be created or destroyed, only interconverted between forms
State the 2nd law of Thermodynamics
Spontaneous processes are those that increase the entropy of the universe
State the 3rd law of therodynamics
At absolute zero the entropy of a perfectly ordered pure crystalline substance is zero.
What is the difference in transfer of heat between work and heat?
Work is transfer of energy into a uniform motion in the surroundings.
Heat is transfer of energy into a disorderly motion in the surroundings.
What is the equation for work when a system expands through constant external pressure
W = - Pex (delta) V
When does a system do maximum work?
when it is in mechanical equilibrium with the surroundings at every stage
What is the relationship between heat transferred and work done for isothermal expansion of an ideal gas?
q = -W
q = -W: what are the conditions of this equation?
This equation only applies to isothermal expansion of an ideal gas
What is the equation for the expansion of an ideal gas to find work done?
W = -nRT ln (Vf/Vi)
What is the relationship between Cv and internal energy?
Cv = (delta)U / (delta)T
