Enthalpy
The change in enthalpy that occurs when reactants are converted to products in a reaction is the same whether the reaction takes place in one step or a series of steps is called?
Hess's Law
Draw a wave and label: one wavelength, nodes, and the amplitude.
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/wave_model/whatarewavesrev3.shtml
Nodes where wave touches dashed line
What is meant by “ground-state”?
The lowest possible energy level for an atom (think: electron configuration)
What is the distance between the nucleus of an atom and its valence shell?
Atomic radius
What phenomenon occurs when electrons are ejected from a metal surface exposed to light at (or above) threshold frequency?
Photoelectric effect
What signs correspond to heat being released or absorbed during a reaction?
(-) Negative: heat released; (+) Positive: heat absorbed
True or False: A particle in motion can be treated as a wave, but a wave cannot exhibit the properties of a particle.
False
What is the total number of orbitals in the full shell with principle quantum number n = 3?
Hint: How many boxes are drawn in the orbital diagram?
9 orbitals:
1s (1 box) + 2s (1 box) + 2p (3 boxes) + 3s (1 box) + 3p (3 boxes)
What trends are seen in the periodic table regarding atomic radius?
Radius increases moving from right to left, increases from top to bottom
True or false: Two electrons in the same atom can not have the same four quantum numbers.
True
Define the standard enthalpy of formation (ΔHf°).
The heat change that results when 1 mole of a compound is formed from its elements in their standard states; “sea level” reference point for all enthalpy expressions
Write the equation with values (i.e. do not solve) to find:
the momentum of a photon of light with a wavelength of 122 nm. Remember that a photon is a particle of light.
mu = h/λ --> (mu) = p = (6.63 x 10-34)/(122 x 10-9)
Which of the following is a legitimate set of three quantum numbers?
a. 1, 0, 0,
b. 2, 0, 0
c. 1, 0, +1
d. 2, 1, +1
e. 2, 2, -1
A, b, d
Which element has the lowest ionization energy: N or O?
N
What feature of the periodic table tells you the principle quantum number (n)?
Row number
Given the following info:
2H2(g) + O2(g) --> 2H2O (g) ΔH = -483.6 kJ/mol
3O2(g) --> 2O3(g) ΔH = +284.6 kJ/mol
What is ΔH for 3H2(g) + O3(g) --> 3H2O(g)?
-867.7 kJ/mol
What is a quantum of energy?
The smallest quantity of energy that can be emitted or absorbed in the form of electromagnetic radiation.
The energy of a single quantum is E = hv, where h is Planck’s constant = 6.63 x 10-34 Js
Express the electron configuration of the element sulfur (S) as a noble gas core.
[Ne]3s23p4
Define the first ionization energy of an atom.
The minimum energy required to remove the most loosely held electron from an atom in the gas phase
Name the principle that implies the following: It is impossible to know simultaneously both the momentum and the position of a particle (in orbit) with certainty.
Heisenberg Uncertainty Principle
This principle lead to the concepts of electron density and atomic orbital (which has a characteristic energy and distribution of electron density).
Use the following data to answer question:
C(graphite) + O2(g) --> CO2(g) ΔHrxn°= -393.5 kJ/mol
H2(g) + 1/2 O2(g) --> H2O(l) ΔHrxn°= -285.8 kJ/mol
2C2H2(g) + 5O2(g) --> 4CO2(g) + 2H2O(l) ΔHrxn°= -2598.8 kJ/mol
Set up the formula corresponding to the standard formation of acetylene (C2H2).
2C(graphite) + H2(g) --> C2H2(g)
Calculate the wavelength of light that has energy 1.32 x 10-23 J/photon. Hint: E = hv
1.51 cm
Write the electron configuration for Se.
1s22s22p63s23p64s23d104p4
What is effective nuclear charge (Zeff)?
The magnitude of positive charge “experienced” by valence electrons in the atom
Calculate the de Broglie wavelength for a 25-g bullet traveling at 612 m/s. Use units kg, m, s.
4.3 x 10-35 m