Ch. 5 Thermochemistry Flashcards
Thermodynamics
the study of energy and its transformations
Thermochemistry
the relationship between chemical reactions and energy changes that involve heat.
Energy
the capacity to do work or transfer heat
work
the energy used to cause an object to move against a force
Heat
the energy used to cause the temperature of an object to increase
Kinetic Energy
the energy of motion
-depends on the mass and speed of the object
Potential Energy
the stored energy that arises from the attractions and repulsion’s an object experiences in relation to other objects
Electrostatic Potential Energy
arises from the interaction between charged particles
Chemical Energy
energy due to the potential energy stored in the arrangements of their atoms
thermal energy
the energy a substance posses because of its temperature is associated with the kinetic energy of the molecules in the substance
Joules
Unit of energy
1 J = 1kg m2/s2
1000J = 1kJ
Calorie
the amount of energy required to raise the temperature of 1g of water from 14.5 C to 15.5 C
1 cal = 4.184 J
System
the portion of the universe we single out for study
-involves the molecules we want to study
Surroundings
everything besides the system
open system
one in which matter and energy can be exchanged with the surroundings
Closed system
systems that can exchange energy but not matter with their surroundings
Issolated system
one in which neither energy nor matter can be exchanged with the surroundings
What do form/s do we experince energy change in
Work and Heat
Force
any push or pull exerted on an object
Work
the energy transferred when a force moves an object
Work Formula
W = Force x distance
The first Law of Thermodynamics
Energy can neither be created nor destroyed
Internal energy (E)
is the sum of all the kinetic and potential energies of the components of the system
- ΔE = Efinal – Einitial
- ΔE = q + w
Endothermic
system absorbs heat
- ΔH = +
