Gen Chemistry 2 (complete) Flashcards
in the first law of thermodynamics, when is work negative and when is work positive
work done ON a system is positive and work done BY the system is negative
what are the three kinds of heat exchange and explain
convection: fluid movement caused by hotter portions rising and cooler fluid sinking
radiation: light colors radiate and absorb less while dark colors absorb and radiate more
conduction: high energy molecules collide with neighbors and give energy until the energy is equally spread out
what equation is used to do calorimeters questions
q=mc∆T, possibly q=C∆T
what is heat capacity
amount of energy a system must absorb to change temperature
what is the first law of thermodynamics
energy can neither be created nor destroyed
what is the formula for specific heat capacity
q=mc∆T
what is the pressure-volume work equation
PV Work = P∆V
what is the second law of thermodynamics
heat cannot be changed completely into work in a cyclical process
can heat be seen to flow from cold to hot object spontaneously?
no, it goes from cold/hot to mixed
what is the third law of thermodynamics
pure crystalline substances at absolute zero have an entropy of zero
where on the graph is pv work?
area under the curve
zeroth law of thermodynamics
everything tends to move toward thermal equilibrium with everything else
calorimeter
device used to calculate enthalpy change
what does delta H mean? give the equation of delta H
enthalpy change; delta H = products - reactants
what is enthalpy?
energy contained within chemical bonds
in an energy graph which part is the delta H? picture a graph with a dotted line with reactants in a higher part than products. the dotted line cuts through the middle of both
delta H is the distance between the products and dotted line
what is delta S
entropy
define entropy
a measure of the randomness or disorder in a system
what is delta G
gibbs free energy
what is gibbs free energy
the amount of “free” or “useful” energy available to do work
a 100g sample of which of the following elements will contain the least number of moles?
Li
Ba
Ca
Na
Ba: largest molar mass means least number of moles
how to convert celsius to Kelvin
Tc +273 =Tk
if delta S > 0, what does that mean for the randomness/disorder
disorder increases, releasing energy into the system that can be used to do work
if delta S < 0, what does that mean for the randomness/disorder
disorder decreases, taking energy from the system, decreasing energy available to do work
in gibbs free energy, what does +deltaG and
-deltaG mean?
+deltaG: nonspontaneous process, energy is required
-deltaG: spontaneous process, energy is made available