lab exam Flashcards
when do we get emission spectra
when electrons drop from a higher energy level to a lower energy level and emit a photon
when do we get absorption spectra
when light passes through an atom and gets absorbed at certain wavelengths
when are electrons emitted due to the photoelectric affect
when the frequency of incident light is greater than the threshold frequency
when are electrons emitted due to the photoelectric affect
when the frequency of incident light is greater than the threshold frequency
what is the energy of the photons related to?
the frequency, the greater the frequency the higher the energy of the photons
what is the intensity of incident light related to
it is directly related to the number of photons emitted
what is the chemical formula for ascorbic acid (Vitamin C)
C6H8O6
what is the heat capacity of an object
the amount of heat needed to change it’s temperature by 1 degree
what can a system contain? what can it not?
it can contain internal energy, it cannot contain heat or work
what is heat
energy in transition
what spectra series corresponds to transitions from n(initial) to a n(final) of 1
the lyman series
what spectra series corresponds to transitions from higher levels to n(final) = 2
balmer series
what spectra series corresponds to transitions from higher energy levels to n(final) = 3
paschen series
in which directions (across, up and down) does atomic radii increase
right to left, and top to bottom
in which directions (across, up and down) does metallic character increase
right to left and down a column
what happens during ionic bonding
a transfer of electrons
what happens during covalent bonding
electrons are shared equally
what is electronegativity
the measure of an atom’s ability to attract the bonding electron density to itself
in which directions (across, up and down) does electronegativity increase
left to right and bottom to top
when is a compound mostly ionic
when the electronegativity difference is greater approximately 2
what is the measure of an atoms ability to attract the bonding density towards itself called
electronegativity
which type of IMF is the strongest
ion-dipole
order the IMFs from weakest to strongest
london dispersion < dipole dipole < h bonding < ion-dipole
which is has good conductivity in water- an ionic or covalent substance? why?
ionic - ionic compounds can dissociate into ions
what are ionic oxides
basic anhydrides
what are covalent oxides
acidic anhydrides
what are the two factors that affect the position of equilibrium
1) the ability of R to draw electrons from O-H
2) the stability of the anion (the further right the stronger the acid
t/f like dissolves like
t
what is molar heat capacity
the amount of heat required to raise the temp of 1 mol of a substance per unit of mol
is pressure constant in a calorimeter
yes
why do we find the extrapolated temp from the graph of a calorimeter experiment
because calorimeters are not 100% efficient
how do you draw the line on a calorimeter graph
draw from the end point to the max, then extend to the y axis
is heat capacity (C) intensive or extensive? why?
intensive- since the substance does not matter
is specific heat capacity intensive or extensive? why?
extensive- the amount of substance is needed to calculate c
is molar heat capacity intensive or extensive? why?
extensive- the amount of substance is needed to calculate Cm
what happens when excited atoms return to a lower state
a photon is emitted
what are applications of emission line spectra
flame test to identify elements, fireworks, florescent lights
in what order does wavelength of the visible spectrum increase
violet<blue<green<yellow<orange<red
what is the equation for the transition between energy levels
delta E = Efinal - Einitial = -Z^(2)Rh( (1/nf^2) + (1/ni^2))
what is a spectrometer used for
obtain the values of absorption (A) as the wavelength of the incident light is varied.
what does a larger A value obtained from a spectrometer mean
more of the incident light is absorbed
what does a longer wavelength of emitted photon correspond to
a lower energy
which emitted photon has the shortest wavelength
n = inf, it has the largest change in energy
what is the most abundant metal
Al
what is the main ore of Al
bauxite
how is Al extracted
via the hall heroult process
what is the ratio of reactants called
stoichiometric factor
what is the stoichiometric point
the equivalence point
where is equivalence point of a titration
when chemically equivalent quantities of reactants have been reached
where is the endpoint of a titration
when the colour change has been observed
what colour does lithium chloride burn
red
what colour does barium chloride burn
green
when one KIO3 particle reacts with ascorbic acid how many ascorbic acid molecules react
3
what is the formula for ascorbic acid
C6H8O6
what is ascorbic acid
vitamin c
in what ratio does vitamin c react with NaOH
1:1
