Exam 3 Flashcards
(72 cards)
Specific heat capacity
amount of (thermal) energy required to change temperature of 1 degree Celsius of 1.0 g material
Exothermic
Delta T < 0
-q
Endothermic
Delta T > 0
+q
calorimetry
the study of heat flow accompanies a chemical process
When does Delta H=q
As long as q is measured with masses equivalent to make ratios in balanced rxn ie Ch4(16g/mol)+2O2 etc eqn question: 16gCh4 in excess O2
-qrxn =
+qsoln
+qsoln=
(mcDeltaT)soln
light admitted at specific energy values in the spectrum, light source produced light of
only specific (or certain) wavelengths
Bohr’s model of the H atom
Neils Bohr
-The presence of 4 distinct bands of light in the visible region of the atomic emission spectrum for hydrogen is based on the way energy reacts with certain electorons
how long do electrons stay in an excited state
short time
+E to system
e- jumps up
from system
e- jumps down
Neils bohr’s model to explain the lines spectrum of hydrogen
based on classical physics explaining macro scale phenomenon: 4 points
four points of Neil boars model
- only specific orbits allowed e- resides on orbits
- e- in orbit has specific E
-e- won’t radiate E
-e- won’t spiral into nucleus - e- jump low –> high must absorb E
e- jumps high –>low must emit E - use precipitate number (n) to identify orbits
e- wants to be
in lowest E
Quantized E
specific amount needed for a specific transition Exact! no more no less
e- from high states to low
can make stops
e- from low states to high
can’t make stops
Delta energy and wavelength
as E goes up wave length goes down
frequency and wavelength
as wavelength goes up frequency goes down
frequency and delta energy
as E goes up frequency goes up
Spectrum
400 0
V I B G Y O R
boars model of H atom was good because
explained absorption and emissions
-H atom only has 1 e-
boars model of H bad because
- only explains few (one electron) systems
- violates classical physics
- violates uncertainty principle:
