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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
The net nuclear charge/net attraction experienced by an electron to the nucleus, taking into account all electronic repulsions.Effective nuclear charge
Effective nuclear charge increases across a period (L to R), true or false.True
Atomic radius increases down a groupTrue
This phenomenon describes the effect on ​equilibrium that occurs when a common ion (an ion that is already contained in the solution) is added to a solution. It generally decreases ​solubility of a solute.The common ion effect
a principle stating that if a constraint (such as a change in pressure, temperature, or concentration of a reactant) is applied to a system in equilibrium, the equilibrium will shift so as to tend to counteract the effect of the constraint.Le Chatelier's Principle
It is the study of the interaction between matter and electromagnetic radiation.Spectroscopy
The distance between 2 successive crests or troughs.Wavelength
The number of waves that pass a reference point in a unit of time. Measured in Hz or s-.Frequency
True/false: frequency and wavelength inversely proportional.True
6.63 x 10^-34 JsPlanck's constant
The maximum displacement from the horizontal axis. Measured in units of length.Amplitude of wave
E=hv where E is enery h is Planck's constant v is frequencyBohr's equation
The quantum of EM action that relates the photon's energy to its frequency. Units are Js.Planck's constant
Why is a C-C bond strong?1) it is a covalent bond meaning there are shared electrons 2) the bond is not polarized, meaning that it is less susceptible to heterolytic fission 3) the BDE for homolysis is 84kcal/mol
6.02 x 10^23Avogadro's number
This is the oscillation of a system at it natural/unforced resonance. It describes when a system is able to store and easily transfer energy between differing storage modes.Resonant frequency
The absorption of EM energy at a frequency such that the photon energy is equal to the quantum excitation energy of the absorbing system.Resonance Absorption
Use of UV-vis spectroscopyMeasuring the the electron transitions that occur in the UV-vis region of the EMS.
Use of IR spectroscopyMeasuring the vibrational and rotational transitions that occur in the IR region of the EMS.
Antibonding orbitalA type of molecular orbital that weakens the bond between two atoms and raises the energy of the molecule as compared to two separated atoms. There may be one or more nodes in the bonding region between the nuclei.
AlkaneMolecule that will not absorb in the UV-vis region of EMS
π→π*, n→π*, n→σ*Electronic transitions that normally produce absorption in the UV-vis region.
Beer-Lambert's LawThe degree of absorption of light at a given wavelength by an absorbing compound in a non-absorbing solvent depends on the concentration of the compound and the path length of the radiation. (The concentration of a chemical solution is directly proportional to its absorption of light)
Beer-lambert's LawA= -log(T) = Σcl
Molar absorptivity constantA measurement of how strongly a chemical species attenuates light at a given wavelength
ChromophoreThe moiety that causes a conformational change of the molecule when hit by light, and consists system of extensively conjugated pi-electrons.
Enthalpy Changeenergy of products - energy of the reactants ΔH = Hp - Hr
Endothermic reactionInvolves bond breaking Energy of the products is greater than that of the reactants Temperature of the reactant vessel decreases (colder)
Exothermic reacrionInvolves bond making Energy of products is less than that of the reactants Heat is given off from, the reaction vessel to the environment
Activation energyThe initial energy absorbed by reactant molecules, causing bond to lengthen and and weaken to form an activated complex or transition state. In this complex, the energy state is high and the complex is highly unstable.
Standard enthalpy of formation (ΔHf)The heat change when when one mole of a substance is formed from its constituent elements in their normal states under standard conditions
Standard enthalpy of combustionThe heat change when i mole of a substance is completely burnt in oxygen under standard conditions.
Standard enthalpy of neutralizationThe enthalpy change when an acid reacts with a base to form 1 mole of water under standard conditions
Standard enthalpy of atomizationThe heat change when 1 mole of gaseous atoms is formed from the element under standard conditions.
1st Ionization energyThe enthalpy change when 1 mole of gaseous atoms is converted to gaseous ions with a singe positive charge
1 electron affinityThe enthalpy change when 1 mole of gaseous atoms is converted to gaseous ions with a single negative charge
8.314 J/K molUniversal Gas constant (R)
Rule stating that when a molecule HX is added onto an asymmetric alkene, the major products is the one in which the H atom attaches itself to the carbon atom already carrying the larger #of H atomsMarkovnikoff's Rule