Chem Ch14 Thermodynamics/Thermochemistry

Thermochemistry

study of energy and its transfermations

Energy

the ability to do work or transfer heat

Work

energy used to cause an object that has mass to move

Heat

energy used to cause the temperature of an object to change

Kinetic Energy

energy with motion (depends on m - mass and v - speed/velocity)

Kinetic Energy Equation

(1/2)mv²

Potential Energy

energy based on position or chemical composition (depends on m - mass, g - gravitational constant/9.8 m/s², and h - height of an object relative to a reference height)

Potential Energy Equation

mgh

Potential Energy in regards to Chem

gravitational force is negligible because potential energy is stored in bonds of molecules

Equation for 1 joule/J

1 (kgm²) / s²

1 L-atm (1 liter x 1 atmospheric unit) =

101.325 J

System

includes molecules being observed in a study

Surroundings

everything surrounding the outside of a system

Work Equations

w = -F x delta d (w - work, F - force, d - distance over the force exerted)

w = -P x delta h (w - work, P - pressure, h - height)

w = -P x delta V (w - work, P - pressure, V - volume)

Note: the F and P can be delta F and delta P depending on information given in the problem

1st Law of Thermodynamics

energy is neither created nor destroyed

Internal Energy

the sum of all kinetic and potential energies of all components in the system

heat plus work equals

delta U or internal energy

work done on the system, work done by the system

+w, -w

State Function

delta E / U (depends only on the present state of the system), all capital letters

Non State Functions

q or w (describes path), all lowercase letters

Enthalpy

internal energy plus the product of pressure and volume, also known as heat (symbol is H)

Enthalpy is

extensive / depends on the amount

Calorimetry

measurement of heat flow