Chemistry Flashcards
How does the energy of a photon change if the wavelength is halved?
The energy doubles
when the wavelength is shorter, and more condensed, the energy is higher
What are halogens?
The elements in Group 17, the elements right before Noble Gases;
F, Cl, Br, I, At
What transition would absorb the longest wavelength on the emission spectrum of the element?
Look for the shortest line, as that has the least amount of energy and has the longest wavelength; think about the red wavelength
What’s the max number of electrons that can be inside the subshell with n=3, l=2
10
l=2, d subshell, 5 orbitals
2 electrons per orbital
5x2=10 electrons
Who’s rule is it that electrons must receive one electron first in each orbital before receiving the next?
Hund’s rule
Is 1s2 2s2 2p6 3s2 3p6 4s1 3d5 the correct electron configuration for Chromium, why?
because of stability. By only having 1 electron in the 4s orbital, Chromium is able to have 1 electron in each of it’s 3d orbitals, this configuration is more stable than by having [Ar]4S23d4
Which is stronger, Ion-dipole or H-bonds for IMF?
Ion-dipole
Ionic bonds > Covalent bonds > Hydrogen bonds > dipole-dipole>LDF
What makes an element have an expanded valence shell(expanded octet)?
Elements with an energy shell ≥ than 3 can be expanded octet, orbitals have to hold more than 8 electrons.
n=3, l=2, which is in the d orbital, which can hold 10 electrons; making it expanded
What are quantum numbers used for?
set of numbers used to describe the position and energy of the electron in an atom are called quantum numbers
4 quantum numbers; principal (n), angular momentum (l orbital shape), magnetic (ml) and spin (ms) quantum numbers.
Which element has the highest ionization energy; B, F, C, N, O?
Fluorine
ionization energy increases from bottom to top, and left to right of the table
The Balmer Series for Hydrogen refers to the visible light emission spectra for electrons going from energy level n to energy level m.
What is the final energy level? (m=?)
options: 1,2,3,4,5
2
Who made the rule that no 2 electrons can have the exact same set of 4 quantum numbers?
Pauli Exclusion
(1) no more than two electrons can occupy the same orbital and
(2) two electrons in the same orbital must have opposite spins
Which electron domain geometries is it impossible to create a triatomic linear molecule?
Tetrahedral, Octrahedral, Trigonal bypyramidal, all are possible, none of the above
all can make a linear molecule/triatomic linear molecule.
i.e Linear triatomic molecules owe their geometry to their sp or sp3d hybridised central atoms. Well-known linear triatomic molecules include carbon dioxide (CO2) and hydrogen cyanide (HCN).
What’s the name of the addition rxn that adds water?
Hydration
One H is added to a carbon and then the OH group gets added onto another Carbon
What’s the name of the addition reaction that adds a hydrogen halide?
Hydrohalligenation
Hess’ law is a ‘state function’ because
quantity depends only on the initial and final states, reactants to products
State function
State functions are values that depend on the state of the substance, and not on how that state was reached
Equation qsystem = - qsurroundings is based on which law of thermodynamics?
first law: energy cannot be destroyed or created
What is a factor that does not affect reaction rate?
product concentration
standard formation reaction
Made from it’s elements in their standard states.
when entropy and enthalpy are both positive, when is it spontaneous?
A. rxn is always spontaneous
B. rxn only spontaneous above a certain temp
C. rxn only spontaneous below a certain temp
D. rxn is never spontaneous
B
If the smell of disinfectants diffuse from a spot where it was applied to the rest of the room, which law of thermodynamics was it?
Second Law; for a spontaneous process, the entropy of the universe increases
If an endothermic reaction is reversible, which of the following is true
A. delta H rev < delta H fwd
B. delta H rev > delta H fwd
C. |delta H rev < delta H fwd|
D. |delta H rev > delta H fwd|
A
If a reversible reaction is exothermic (gives out energy) in one direction it is endothermic (takes in energy) in the other direction.
What is a negative entropy change?
Negative entropy means that something is becoming less disordered.
i.e Ag+(aq) + Cl-(aq) —> AgCl(s)
