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
pH vs pka definition
pH: measure of H+ ions in the solution; it can change as the solution composition changes
pKa: does not change unless the compound itself changes
if pH is greater than pKa, which is more, acid or base? what about the solute?
base; solute acts as an acid
if pH is less than pKa, which is more, acid or base? what about the solute?
acid; solute acts as a base
arrhenius acids produce what kind of solution? arrhenius bases produce?
acids produce H+ in solution, bases produce OH-
brønsted-lowry acids donate what
what do bases do
acids donate H+ and bases accept them
HCl + SO4^-2 —–> Cl- + HSO4-
acid. base. conjugated
base acid
lewis acid does what with electrons
lewis base does what with electrons
lewis acid: accept electrons
lewis base: donate electrons
what can amphoteric substances do? give 2 examples
can act as either an acid or base
ex. H2O or HSO4-
how do you calculate pH
make an example of trying to calculate the pH 1
pH 7?
pH 12?
pH 1= 1.10^-1 m [H+]
pH 7= 1.10^-7 m [H+]
pH 12= 1.10^-12m [H+]
which of these will dissociate in water? strong acid
strong base
weak acid
weak base
both strong acid and base will dissociate 100% in water
both weak acid and base will only partially dissociate
what are some examples of strong acids
HI, HBr, HCl, HNO3, HClO4, HClO3, H2SO4, H3O+
what are some examples of strong bases
NaOH, KOH, LiOH etc
NH2-, H-, Ca(OH)2, Si(OH)2, Ba(OH)2, Na2O, CaO
how do you know if it is a strong acid
if it is an ionic compound with H+ as the cation, it is a strong acid
how do you know if it is strong base
if it has OH, it is a strong base
henderson-hasselbach equation
pH=pKa + log [A-]/[HA]
what is the henderson-hasselbach equation used for
used to determine the relationship between acids and bases
what is the salt of a weak acid
conjugate base plus a cation
what is the salt of a weak base
conjugate acid plus an anion
what is titration
process of adding acid of a known concentration to base of an unknown concentration (or vice versa) to figure out the unknown concentration
how does a graph look for Strong acid/Strong base? think how it looks on pH
starts at low Ph and ends at a high pH
how does a graph look for Strong Base/strong acid? think how it looks on pH
starts at high pH and ends at low pH
how does a graph look for weak acid/weak base? think how it looks on pH
starts mid-low pH and ends at high
how does a graph look for weak base/weak acid? think how it looks on pH
starts mid high and ends mid low
if a reaction is at max entropy, what does that mean?
it is at equilibrium
equation of Ka
Ka = [H+][A-]/[HA]
equation of Kb
Kb= [OH-][HA]/[A-]
is CO2 polar or non polar
non polar
there is even distribution
in the case of the same liquid being in two different containers, and the pressure is measured at 10cm deep, how does the pressure differ
it doesn’t because the height is the same, doesn’t matter the shape
and the liquid is the same
what is boyles law
P1V1=P2V2
what is charles law
V1/T1=V2/T2
how do you find the number of neutrons in an element
atomic mass-atomic number
what is the volume at STP
22.4L
1mole of gas = normal volume
what is visible light in
400-700nm
what wavelength do you need to see bacteria
400-700
list the wavelengths from big to small
low frequency to high
radio
micro
IR
visible
UV
xray
gamma
dipole movement
separation of partial charges across polar bonds
if you are given Radium-226, how would it change with alpha decay
(note: atomic number is 88)
it would go from 226/88 Ra to 222/86 Rn
bc alpha means lose 4 on top and 2 on bottom
if you are given Radium-226, how would it change with beta decay
(note: atomic number is 88)
it would go from 226/88 Ra to 226/87 Fr
bc beta means the top number stays the same but the atomic number/bottom decreases by 1 (the element does change bc atomic number changed)
if you are given Radium-226, how would it change with gamma emission
(note: atomic number is 88)
it would go from 222/88 Ra to 226/88 Ra
it would stay the same bc no nuclear conversion or release of energy is happening
if Ka is given and you are asked to find Kb, what do you do?
14-Ka=Kb
