MCAT General Chemistry Flashcards
__is equivalent to the number of protons in the nucleus of an atom
Atomic number (Z)
__is the principle that atomic orbitals are filled one at a time, starting with the orbital that has the lowest energy and then filling upwards
Aufbau principle
A model of the distribution of electrons in an atom based on the assumption that the electron in a hydrogen atom is in one of a limited number of orbits
Bohr model
The temperature at which the vapor pressure of a liquid is equal to the external or atmospheric pressure
Boiling point
The energy needed to homolytically break a bond to give two atoms in the gas phase
Bond-dissociation energy/ Enthalpy
A covalent bond formed as a result of a Lewis acid-base reaction, most often formed between a metal atom and a nonmetal atom
Coordinate covalent bond
A compound in which one or more ligands are coordinated to a metal atom
Coordination compound
A three-dimensional solid formed by regular repetition of the packing of atoms, ions, or molecules
Crystal
A substance in which the electrons are all paired
diamagnetic
Anything with two equal but opposite electrical charges, such as the positive and negative ends of a polar bond or molecule
Dipole
Capable of being drawn into sheets or wires without breaking; this is a property of metals
Ductile
The energy given off when a neutral atom in the gas phase picks up an electron to form a negatively charged ion
Electron affinity
A type of beta decay where the nucleus of an atom captures an electron and converts a nuclear proton into a neutron
Electron capture
A vertical column of elements in the periodic table
Family
A high energy SHORT wavelength form of electromagnetic radiation emitted by the nucleus of an atom that carries off some of the energy generated in a nuclear reaction
Gamma ray
A vertical column or family on the periodic table can also be called a __
group
Rule for placing electrons in equal energy orbitals which states that:
-Electrons are added with parallel spins until each of the orbitals has one electron, before a second electron is placed in a given orbital
Hund’s rule
A short lived separation of charge, or dipole, of a nonpolar atom or molecule caused by the electrostatic influence of a nearby polar atom or ion
Induced dipole
An atom or molecule that accepts a pair of electrons to form a new coordinate covalent bond, almost always a metal, positively charged ion, or both
Lewis acid
An atom or molecule that donates a pair of electrons to form a new coordinate covalent bond. Almost always a nonmetal, with a pair of nonbonding electrons
Lewis base
Intermolecular forces that arise from interactions between an instantaneous dipole/induced dipole pair. Typically, these are the weakest of all intermolecular forces.
London dispersion forces
Something that can be hammered, pounded, or pressed into different shapes without breaking (common metal property)
Malleable
The total number of protons and neutrons in the nucleus of an atom
Mass number
The temeprature at which the solid and liquid phase of a substance are in equilibrium at a aprticular external pressure
Melting point
A substance that contains two or more elements or compounds that retain their chemical identities and can be separated by a physical process
Mixture
The formula representing the number and type of constituent atoms in a compound
Molecular formula
A solid, such as diamond, in which every atom is covalently bonded to its nearest neighbors to form an extended array of atoms rather than individual molecules
Network solid
A compound that contains one or more unpaired electrons and is attracted into a magnetic field
Paramagnetic
The maximum number of electrons in any given orbital is 2 and they must have opposite spin
Pauli exclusion principle
A horizontal row in the periodic table
Period
__is what determines what the element is
Atomic number
When does B decay occur?
When an unstable nucleus contains too many neutrons, converts a neutron to a proton and electron, move Right on periodic table
When does Positron emission occur?
This occurs when nucleus contains too few neutrons move Left on periodic table
If you form ions the radius will_____
Decrease as electrons are removed (because the ones that are left will be held closer to nucleus)
-Increase as electrons are added
Ex: X+
The amount of energy necessary to remove the least tightly bound electron from an isolated atom is called the atoms __
ionization energy
As we move from left to right across a period, or up a group, the ionization energy ___
increases since the valence electrons are more tightly bound
The energy associated with the addition of an electron to an isolated atom is known as the atoms ___
electron affinity
The halogens have a ___electron addinity value, since the ADDITION of an electron would give them the octet configuration
large NEGATIVE
The noble gases and alkaline earth metals have a ___affinity because added electron begins to fill a new level or sublevel and destabilizes the electron configuration
POSITIVE electron affinities
The temperature (-273.15C or 0K) at which the volume and pressure of an ideal gas extrapolate to zero according to the ideal gas law
Absolute zero
Forms of a pure element with which different structures and therefore different chemical and physical properties, such as O2 and O3 or diamond and graphite
Allotropes
A process that leads to an increase in the free energy of a system and is therefore NOT spontaneous Grxn is positive
Endergonic
A chemical reaction that absorbs heat from the surroundings : Hrxn is positive
Endothermic
The total potential energy in a substance due to intermolecular forces and covalent bonds
Enthalpy (H)
The change in the enthalpy that occurs during a chemical reaction. The difference between the sum of the enthalpies of the products and the reactants
Enthalpy of reaction (Hrxn)
A process that leads to a decrease in the free energy of a system and is therefore spontaneous G is negative
Exergonic
A chemical reaction that releases energy to the surroundings H is negative
Exothermic
The total energy in the universe is conserved: energy is neither created nor destroyed, but may change from one form to another
First law of thermodynamics
The energy associated with a chemical reaction that can be used to do work.
Free energy Gibbs (G)
The heat given off or absorbed in a chemical reaction does not depend on whether the reaction occurs in a single step or in many steps
Hess’s law
Processes that increase the entropy in the universe are spontaneous
Second law of thermodynamics
A reaction in which the product are favored
G is negative
Ecell is positive
Spontaneous reaction
The change in the enthalpy that occurs during a chemical reaction that leads to the formation of one mole of a compound from its elements in their standard states at standard conditions
Standard heat of formation (Hf
State in which T = 298 K
P =1 atm
and all concentrations are 1 M not STP
Standard state/condition
Standard temperature and pressure (STP)
State in which T =273 K (OC)
P= 1 ATM generally used when referring to gases
A quantity whose value depends only on the state of the system and not its history; X is a state ufnction, if and oly if, the value of deltaX does not depend on the path used to go from the initial to the final state of the system
State function
Melting, freezing, and boiling are all examples of ___
physical changes
A key property of a physical change is that no __ bonds are made or broken
Intramolecular bonds are made or broken
Physical change affects only the ____ forces between molecules or atoms
Intermolecular forces
Going from a solid to a liquid ____
Melting (fusion)
Going from a liquid to a solid __
Freezing (crystallization)
Liquid to gas ___
vaporization (boiling)
Gas to Liquid ___
condensation
Solid to gas ____
Sublimation
Gas to solid___
Deposition
Going from solid -> liquid -> or solid ->L
___ heat,
internal Kinetic energy___
Entropy__
Heat is absorbed
Internal kinetic energy increase
Entropy increases
Going from Gas -> liquid ->solid or Gas -> soli
___heat
Internal Kinetic energy___
Entropy___
Heat is released
Internal KE decrease
Entropy decreases
The amount of heat required to cause a change of phase depends on two things:
- The type of substance
- The amount of substance
Formula for the heat accompanying a phase transition is =
q = n x H(dependent on phase change)
q = heat
n = number of moles
delta H = heat of transition
If delta H (heat of transition) and q are positive =
heat is absorbed
When a substance absorbs or releases heat one of two things can happen:
- temperature changes
- a phase change will occur
BUT NOT BOTH AT THE SAME TIME
A substance’s specific heat is an ____ of that substance and tells us how resistant it is to changing its temperature
Intrinsic property
