Midterm 2 (Chapters 5-6) Flashcards
work
the energy used to cause an object to move against a force
heat
the energy used to cause the temperature of an object to increase
equation for kinetic energy
Ek = ½mv^2 (joules)
equation for potential energy
m x g x h
equation for electrostatic energy
Eel = kQ1Q2/d
k = 8.99x10^9 J-m/C^2
what is a joule
joule (J): 1 Kg-m^2/s^2
calorie to joule
1 cal = 4.184 J
open system
one in which matter and energy can be exchanged with the surroundings (e.g. an uncovered pot of boiling water)
closed system
can exchange energy but not matter with their surroundings (e.g. mixture of hydrogen gas and oxygen gas in a cylinder fitted with a piston – energy can enter or leave system as heat or as work done on piston)
isolated system
one in which neither energy nor matter can be exchanged with the surroundings
work equation
w = F x d
F = m x g
w = m x g x d
what is the first law of thermodynamics?
energy is conserved
internal energy
E
ΔE equation
ΔE = Efinal - Einitial ΔE = q + w
examples of state functions
S,G,E,H, temperature, pressure, volume
enthalpy equation
H = E + PV
equation for PV work
w = -PΔV
ΔH equation
ΔH = ΔE + PΔV
ΔH = Hproducts - Hreactants
what is heat capacity
the heat capacity of an object is the amount of heat required to raise its temperature by 1 K or 1 C° - the greater the heat capacity the greater the heat required to produce a given increase in temperature
what is molar heat capacity
the specific heat capacity for one mole of a substance - you get it from the specific heat
equation of specific heat
Cs = q / (m x ΔT)
solution and reaction relationship in coffee cup calorimeter
qsoln = specific heat of solution x grams of solution x ΔT = -qrxn
bomb calorimeter equation
qrxn = -Ccal x ΔT
standard enthalpy of formation equation
ΔH°rxn = Σn ΔHf°(products) - Σm ΔHf°(reactants)
speed of light
3.00 x 10^8 m/s
units for wavelength
meters
units for frequency
Hz or 1/s
relationship between frequency and wavelength
c = λν
electromagnetic spectrum
Radio→ microwave →infrared → ultraviolet → x-rays → gamma
radio: longest wavelength, shortest frequency, lowest energy
relationship between energy and frequency
E = hν
h = 6c626 x 10^-34
Rydberg equation
calculates wavelengths of spectral lines of hydrogen
1/λ = RH (1/n^21 – 1/n^22)
RH = 1.096776 x 10^7
n^2 is larger
equation for energy for orbits of hydrogen atom
E = (-2.18 x 10^-18)(1/n^2)
energy
ΔE = Ef – Ei = Ephoton
energy of an orbital
E = (-2.18 x 10^-18)(1/n^2f - 1/n^2i)
DeBroglie equation
λ = h/mv
heisenberg uncertainty equation
Δx*Δmv ≥ h/4π
if you know the speed to an uncertainty of 1% then its an uncertainty of (.01)(5 x 106 m/s)
n
principle quantum number - tells which shell
l
angular momentum quantum number - tells which subshell (s,p,d,f,)(s = 0, p = 1, etc.)
ml
magnetic quantum number - tells which orbital - values of -l to +l
s = 1 p = 3 d = 5 f = 7
each orbital has 2 electrons
ms
quantum spin number - tells if spinning up or down - values of +1/2 or -1/2
shape of s orbital
spheres
shape of p orbital
dumbbell shaped - two lobes of opposite charge
shape of d orbitals
4 balloons tied together
degenerate orbitals
all orbitals of a given subshell (such as the five 3d orbitals) have the same energy as one another. Orbitals with the same energy are said to be degenerate
hunds rule
states that for degenerate orbitals, the lowest energy is attained when the number of electrons having the same spin is maximized = electrons occupy orbitals singly to the maximum extend possible
pauli exclusion principle
states that no two electrons in an atom can have the same set of four quantum numbers n, l, ml, and ms
elements that are exceptions to the regular electron configuration
Cr, Cu, Mo, Ag, Au
what are the 3 phenomena of light?
1) the emissions of light from hot objects (black light radiation)
2) the emission of electrons from metal surfaces on which light shines (photoelectric effect)
3) the emission of light from electrically excited gas atoms (emission spectra)
what is a quantum?
the smallest quantity of energy that can be emitted or absorbed as electromagnetic radiation
Bohr Model
1) only orbits or certain radii corresponding to certain specific energies are permitted for the electron in a hydrogen atom
2) an electron in a permitted orbit is “allowed” and those that are allowed do not radiate energy and therefore don’t spiral into the nucleus
3) energy emitted or absorbed by the electron as the electron moves from one allowed energy state to another
- can only explain the line spectrum of hydrogen
energy of an electron
the more negative the energy is the more stable the atom is (lowest energy is for n = 1, ground state)
DeBroglie
suggested that an electron moving around the nucleousof an atom behaves like a wave
total number of orbitals in a shell
n^2
node
points where the amplitude of the wave is 0
