Theromydynamics

# Theromydynamics - First and foremost, be careful to...

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First and foremost, be careful to distinguish thermodynamics from kinetics or equilibrium whenever you need to (like in the presence of a catalyst) - A catalyst lowers the activation energy, but does not affect an equilibrium constant, enthalpy, entropy or free energy in any way. Remember fundamental theories: an increase in disorder of one system will be complemented by a decrease in disorder of the other system. - Recall: dropping oil in water causes the water molecules to surround the oil in a cage-like structure, and the oil molecules will aggregate together (i.e. the oil will increase in order, and therefore decrease in disorder). The water molecules will be more disorderly. When we put energy into a system (i.e. make an ice cube melt), we are increasing the energy of the system (+). When water freezes, heat is given off (-). First law of thermodynamics: the total energy of the universe is constant - Energy cannot be created or destroyed. - Energy is therefore transferred Energy is transferred into some other form such as heat or work . Δ E = q + w E internal α T - We increase the temperature; we increase the internal energy of the system. If we increase the temperature of a gas, it will want to expand - Why? increase the temperature will increase the volume of the system if the pressure if kept constant - If we add heat to a system and keep the volume and pressure constant, energy will be transferred as heat (we can tell because we feel the gas and cylinder getting hotter) - If we let the gas sit, then over time energy will be lost as heat Work = -P external* ΔV - A negative value for work implies that work is being done by the system; and a positive value implies that work is being done on the system Gases lose energy as they expand since

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## This note was uploaded on 11/07/2010 for the course CBN 356 taught by Professor Merill during the Spring '08 term at Rutgers.

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Theromydynamics - First and foremost, be careful to...

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