Studied by 15 people
Looks like no one added any tags here yet for you.
Thermodynamics
The study of energy and its transformations.
Theromchemistry
The portion of thermodynamics that is interested in the relationships between chemical reactions and energy changes that involve heat.
Energy
The capacity to do work or transfer heat.
Work
The energy used to move an object against a force.
Heat
The energy used to cause the temperature of an object to increase
Two types of energy are
Kinetic and potential
Kinetic energy
The energy of motion which depends on the mass and velocity of an object
Ek = ½ mv²
Formula for kinetic energy. (1/2 mass times velocity sqaured)
Potential energy
The stored energy by virture of position of an object relative to other objects.
One form of Potential energy is
Electrostatic
Where do electrostatic energy come from?
It comes from the interactions of charged particles.
Eel =kq1q2/d
Coulomb’s Law (K is constant of proportionality, q is the charge of the particle, d is the distance)
K
8.988×109 Nm2/C2
charge of proton
1.6 x 10-19 C (coulombs)
The charge of electron
-1.60217663 × 10-19 coulombs
If Eel > 0 and q1 q2 are near each other
Smaller separation, greater repulsion, Higher Eel (Higher Potential energy)
If Eel > 0 and q1 q2 are far from each other
Greater separation, less repulsion, lower Eel (lower potential energy)
If Eel <0 and q1 q2 are close to each other
Smaller separation, greater attraction, lower Eel (lower potential energy)
if Eel < 0 and q1 q2 are far away from each other
Greater separation, less attraction, higher (less negative) Eel (higher potential energy)
(in) Thermodynamics
everything is labeled the universe
the system
The portion of the universe that we are interested in studying. Consists of reactants and products of the reaction
the surroundings
Everything else in the universe
What can energy do in a cylinder piston
Energy can enter or leave the system as heat or as work done on piston
What is the system
The elements (H2 and O2)
What is the surroundings?
cylinder, piston, and everything beyond
If matter can not leave the system, but heat (energy) can, what type of system is the cylinder piston
Closed system
Open system
Heat (energy) can exchange and mass can exchange
Closed system
Heat (energy) can exchange. Mass cannot exchange
Isolated system
Heat (energy) cannot exchange, Mass cannot exchange
The first law of Thermodynamics
Energy can be neither created nor destroyed. Any energy lost by a system must be gained by the surroundings, and vice versa
Internal energy (E)
a system is the sum of all kinetic and potential energies of the components of the system
∆E = Efinal-Einitial
Change of energy formula
∆E negative when
Energy lost to surroundings, internal energy of system decrease
∆E is positive when
Energy gained from surroundings, internal energy of system increases
∆E = q + w
Internal energy formula (q is heat, w is work)
When q is positive
system gains heat
When q is negative
system loses heat
When w is positive
work done on system
When w is negative
work done on system
when ∆E is positive
net gain of energy by system
When ∆E is negative
net loss of energy by system
Exothermic
A process that release energy in the form of heat
Endothermic
A process that absorbs heat
Exothermic reaction
when a system realeases heat to the surrounding during a reaction, causing the temperature to increase making reaction feel warm
endothermic reaction
when a system absorbs heat from the surroundings during a reaction, causing the temperature to decrease making the reaction feel cold
Energy is released when chemical bonds are formed.
Energy is consumed when chemical bonds are broken.
Internal energy
is an example of a thermodynamic state function.
State function
a property of a system that is determined by specifying a system’s condition (or state) and not by how it got to that state.
Note 
Flashcard (36)