Chapter 6.1 Forms of Energy and Their Interconversion Flashcards
system
the part of the universe we are focusing on
surroundings
everything else other than the system
internal energy (E)
the sum of both potential energy and kinetic energy of a system
ΔE definition
the difference between the internal energy AFTER the change (Efinal) and BEFORE the change (Einitial)
ΔE equation
ΔE = Efinal - Einitial = Eproducts - Ereactants
What happens when the Energy of system DECREASES
system releases some energy in a transfer TO the surroundings:
Efinal
What happens when the Energy of system INCREASES
system absorbs some energy in a transfer FROM the surroundings:
Efinal > Einitial so ΔE > 0
Heat (thermal energy) [q]
the energy transferred as a result of a difference in temperature between the system and the surroundings
Work (w)
the energy transferred when an object is moved by a force
Equation for the total change in a system’s internal energy
ΔE = q + w
What happens when work is done BY a system
system releases energy as work, so w is negative:
Efinal
What happens when work is done ON a system
energy is transferred as work done BY the surroundings ON the system, so w is positive:
Efinal > Einitial, so ΔE is positive
Law of Conservation of Energy
energy is conserved: the total energy of a system + the surroundings remains constant
1st Law of Thermodynamics
the total energy of the universe is constant:
ΔEuniverse = ΔEsystem + ΔEsurroundings = 0
Units of Energy
1J = 1kg · m/s²
