Unit 2 Flashcards
system
chemical reaction
surroundings
everything that is not the chemical reaction
open system
freely exchanges energy and matter with surroundings
closed system
does not allow certain transfers in/out of system
isolated system
cannot exchange either energy or matter outside the system
work
work performed by a system is the energy transferred by the system to its surroundings
energy
the capacity to do work or produce heat
kinetic energy
energy due to the motion of particles like thermal energy
potential energy
stored in the chemical bonds
chemical energy
energy released when bonds form in a reaction
first law of thermodynamics
energy cannot be created or destroyed, it can only be transferred in different forms
internal energy
sum of potential and kinetic energy of a system
state function
depends only on initial and final stated, not the way to get there
path function
depends on the path you take to get somewhere
when measuring internal energy
you are measuring changes in it (delta E)
work is done on system
compression +ve sign
work is done by system
expansion -ve sign
q heat is gained from surroundings
+ve
q heat is lost to surroundings
exothermic -ve
when a gas is compressed
work is done on system so it is +ve, p is always positive
exothermic
head is going out, surroundings get warmer
endothermic
head is going in, the surroundings get cooler
how to tell if ends or exo
- sign of Q and delta H (+ve is ends, -ve is exo)
- surroundings get cooler/warmer
- where e (energy) is placed in a reaction (reactant is ends, products is exo)
- potential energy diagrams
potential energy diagrams
y axis- potential energy
x-axis- reaction progress
Include states!
- see diagram for more