Flashcards in Flashcards Deck (264):
Can molecules with polar bonds be non polar?
Yes if there is no net dipole moment
What is the shape of an s orbital?
what is the shape of p orbital?
Which type of bonds form between atoms with small differences in electronegativity (.4-1.7)?
polar covalent bonds
Which type of bond forms between atoms with the same electronegativities?
non polar covalent bonds
What is a coordinate covalent bond?
one in which a pair of bonding electrons originates from just one of the atoms.
(T/F) A dipole moment exist when a molecule has a separation of positive and negative charges.
What is the formula for calculating formal charge on an atom involved in a covalent bond?
Formal charge= V-(1/2 N bonding + N nonbonding)
What are resonance structures?
2 or more non-identical lewis structures for the same molecules
(T/F) A lewis structure with small or no formal charges is preferred over one with large formula charges.
Should a negative formal charge be placed in highly electronegative atoms or weakly electronegative atoms?
highly electronegative atoms.
what are the bond orders of single, double, and triple bonds?
(T/F) A triple bond is longer than a single bond..
What is a bond energy?
amount of energy required to separate two bonded atoms
Can both bonding and nonbonding electrons be valence electrons?
nonbonding e- = not involved in a bond
bonding e- = involved in a bond
Which type of elements contains the halogens?
Which group of elements contains alkaline earths?
Which group of elements contains noble gases?
Which groups of elements contain the transition metals?
groups IB to VIIIB
what is an ionic bond?
transfer of electrons between two atoms
what is a covalent bond?
sharing of electrons between two atoms
what is a polar covalent bond?
has properties of ionic and covalent bonds. electrons are shared but not equal.
what is a cation?
(T/F) Metals are found on the left side of the periodic table and are good conductors of electricity and heat.
(T/F) Non metals are found in the middle of the periodic table and are malleable, ductile and shiny.
(T/F) Metalloids are found between the metals and nonmetals and have varying properties.
Which group of elements contains the alkali metals?
What is the electron affinity trend within the periodic table?
increases left to right across a period & up a group.
(T/F) Group VIIIA elements have high electron affinities.
What is electronegativity?
measure of attraction an atom has for the electrons in a chemical bond.
What is the electronegative trend within the periodic table?
increases left to right across a period and up a group.
What happens to the number of electrons when one moves from left to right across a row?
added as you move across a row.
Are electrons more tightly held or less highly held as one moves down a column?
What is the atomic radii trend within the periodic table?
decrease as you move from left to right across a period and up a group.
Does a period run horizontally or vertically?
Does a group run horizontally or vertically?
(T/F) Groups have the same valence configuration and have similar chemical properties.
Which group A or B contains the representative elements?
(T/F) one amu is equal to 1/12 the mass of a carbon-12 atom.
how many particles are in a mole?
6.02 x 10 ^23
what is atomic weight?
reflects the number of grams per mole of the element. The atomic weight is usually derived from a weighted average of the naturally occurring isotopes of the element.
what is an isotope?
different form of the same element due to a different number of neutrons.
What are the 3 steps for determining geometric configuration?
1. draw lewis structure
2. count bonding and non bonding electron pairs in the valence shell of the central atom
3. arrange the electron pairs around the central atom so that they are as far apart as possible.
what is an anion?
negatively- charged ion.
which type of bonds forms between two atoms with substantial differences in electronegativities (>1.7)?
(T/F) all atoms bond according to the "octet rule"
what are some characteristics of ionic compounds?
conduct electricity in solution
what is ionization energy?
energy required to completely remove an electron from an atom.
compare the values of the first ionization and second ionization energy of an atom.
second ionization higher than first
what is electron affinity?
energy released when an atom accepts an electron.
How s a photon's energy related to its wavelength?
energy is inversely proportional to wavelength
How is a photon's energy related to its frequency?
energy is proportional to frequency
What is a paramagnetic material?
What is a diamagnetic material?
no unpaired electrons
How many fourth quantum numbers (ms) are possible for an electron?
What are they?
+1/2 and -1/2
What is Hund's rule?
electrons will fill to create the max number of half-filled orbitals.
what are the first four subshells?
s,p,d and f
what is the formula for the max number of electrons allowed in a subshell?
what does the magnetic (3rd) quantum number (ml) represent?
represent an orbital within a subshell. The possible values range from -l to l
How many orbitals can each subshell accommodate?
What are three types of intermolecular forces?
state the intermolecular forces in order of increasing strength.
which molecules, polar or non polar, typically have higher boiling points?
polar molecules typically have higher boiling points.
How many more protons are in a carbon-14 from than in a carbon-12 atom?
what is an atomic emission spectrum?
electrons fall to their ground state
what is an atomic absorption spectrum?
electrons are excited to higher energy levels.
define Heisenberg uncertainty principle.
it is impossible to know both the momentum and position of an electron at the same time.
what are valence electrons?
electrons farthest from the nucleus, as well as many electrons available for bonding.
Define the Pauli exclusion principle?
no two electrons in an atom can have the same quantum numbers.
what does the principal (1st) quantum number (n) represent?
what is the maximum number of electrons allowed in the second shell (n=2)?
What does the azimuthal (2nd) quantum number (l) represent?
Classify the Rxn:
A+X -> AX
Combination or additon
Classify the Rxn:
AX -> A + X
Classify the Rxn:
AX + B -> BX + A
Classify the Rxn:
AX+ BY -> AY + BX
Classify the Rxn:
HA (aq) + BOH (aq) -> AB (aq) + H2O
What is an empirical formula?
simplest whole number ratio of the element in a compound.
What is a molecular formula?
actual number of atoms each element present in a molecule of the compound.
what is the formula for calculating % composition
mass of X compound / MW of compound x 100%
What is molar mass (molar weight)?
Number of grams per molecule
what is the formula for gram equivalent weight?
Molar mass / n = Gram equivalent weight.
what is the formula for calculating equivalents?
Weight of compound/ Gram equivalent weight= equivalents
How do increasing temp and reactant concentration affect the rate of the reaction?
increases the rate of most reactions.
can the medium in which a reaction takes place affect the reaction rate?
how does a catalyst increase reaction rate?
by decreasing activation energy
what is the reaction rate of the following one step reaction:
2A + B -> A2B
Rate = k [A]^2 [B]
what is the enthalpy change of a reaction?
difference between potential energy of the products and the potential energy of the reactants
what is the general formula for the rate law of the following reaction?
aA + bB -> cC + dD
rate= k [A]^x [B]^y
What is the reaction order for the following rate law?
rate= k [A] [B]^2
Reaction order =3
(x=1, y=2, and order =x+y)
Is the rate of a zero order reaction dependent on the concentration of the reactants?
No, a zero order reaction has a constant rate that is independent of the concentration of reactants.
what is an elementary reaction?
reaction that can not be decomposed into other reactions
(T/F) A complex reaction can be broken down into two or more elementary reactions.
what is an intermediate?
complex that appears during the course of a reaction but does not appear in the net reaction or as a final product.
what is the rate determining step of a reaction?
slowest step of a reaction
what is theoretical yield?
amount of product that can be predicted
what is actual yield?
amount of product actually isolated from the run experimentally
What is percent yield and what is the formula for calculating it?
relationship between actual yield and theoretical yield
actual/theoretical x 100%
What is the equilibrium constant expression for the following reaction:
A+ 3B -> 2C + 2D
Keq= [C]^2 [D]^2 / [A] [B]^3
Do pure solids or liquids appear in an equilibrium constant expression?
Does Keq for a reaction remain constant at all temperatures?
If there is much more product than reactant at equilibrium, what can be said of Keq (as compared to 1)?
If Keq is very small compared to 1, then what can be said about the amount of reactants and products at equilibrium?
According to Le Chatelier's principle, in which direction will equilibrium shift if products are removed?
will shift to favor the forward reaction.
(T/F) Increasing the pressure of a system will shift equilibrium so as to increase the number of moles produced.
Increasing pressure will shift equation so as to produce fewer molecules of gas.
What is an isolated system?
an isolated system can not exchange energy or matter with its surroundings.
What is a closed system?
a closed system can exchange energy but can not exchange matter with its surroundings.
what is an open system?
an open system can exchange both energy and matter with its surroundings
what is an isothermal process?
process that can occur @ constant temp.
what is an isobaric process?
process that takes place @ constant pressure.
what is an adiabatic process?
process to which no heat exchange occurs between the system and the surroundings
(T/F) heat absorbed by a system is considered positive and heat lost by a system is considered negative.
what is an endothermic process?
process that absorbs heat from the surroundings.
what is an exothermic process?
what is the formula for calculating heat (q) absorbed or released by a process.
q= (mass)(heat capacity)(change in temp)= mcAt
what is the formula for calculating Delta Hrxn?
(sum of Delta Hf of products)-( Sum of Delta Hf of reactants)
Does a positive Delta H correspond to an endothermic or exothermic process
Does a negative Delta H correspond to an endothermic or exothermic process?
What is standard heat of formation ( Deta Hf)?
enthalpy change that occurs when one mole of a compound is formed from its elements in their standard states.
What is the Delta Hf of an element in its standard state?
(T/F) Hess's law states that enthalpies of reactions are additive.
If the Delta H of a forward reaction is -220kJ, what is the Delta H of the reverse reaction?
What is bond dissociation energy?
amount of energy required to break a particular bond in one mole of gaseous molecules.
What is entropy?
measure of disorder or randomness of a system.
When does a system reach max entropy?
What is the Gibb's free energy equation? ΔG=
ΔG= ΔH- T ΔS
How does the value of ΔG correlate with the spontaneity of a reaction?
Δ G is negative for spontaneous rxn.
Δ G is positive for non-spontaneous run
What is the value of ΔG for a system @ eq?
(T/F) A reaction with (+) ΔH and (-) ΔS is always spontaneous.
Under what conditions will a run with (+) ΔH and (+) ΔS be spontaneous?
@ high temp
under what conditions will a reaction with (-)ΔH and (-) ΔS be spontaneous?
@ low temp
what is standard free energy, ΔG?
process occurring @ 25 C, 1 atm of pressure and when the concentrations of all reactant and products are 1M
what is standard free energy formation ΔGf?
free energy change that occurs when 1 mol of a compound in its standard state is formed from its elements in their standard states.
what is the formula relating ΔG to Keq?
ΔG= -RT ln Keq
(T/F) Once a reaction commences:
ΔG= ΔG+ RTln Q
What are the three phases of matter?
What is standard pressure in atm, mm Hg and torr?
1atm=760 mmHg= 760 torr
What is standard term in Kelvin? celsius?
(T/F) an ideal gas represents a hypothetical gas whose articles take up no volume and experience no intermolecular forces.
What is Boyle's law?
under isothermal conditions, pressure is inversely proportional to volume.
What is Charles Law?
under constant pressure, volume is directly proportional to absolute temp.
(T/F) Avogadro's principle states that at constant temp and pressure, volume is directly proportional to the number of moles of gas.
what is the ideal gas law?
what is the difference between I.P and Ksp?
I.P is defined with respect to initial concentrations.
Ksp is defined with respect to the concentrations of a saturated solution at equilibrium.
(T/F) Metals, which are on the left side of the periodic table, generally form positively-charged ions. non-metals on the right side generally from negative-charged ions.
What is an electrolyte?
solute whose solution is conductive
What is the formula for percent composition by mass?
mass of solute/ mass of solution x 100%
What is the definition of mole fraction (X)?
moles of compound/ total number of moles.
What is the definition of molarity?
moles of solute/ L in solution
what is the definition of molality?
moles of solute/ Kg of solvent
what is the definition of normality?
GEW of solute/ L of solute.
(T/F) A solution which is diluted is related to its initial concentration as follows: M1V1= M2V2
What is the Arrhenius definition of an acid?
Arrhenius acid: produces H+ in aq solution.
Arrhenius base: produces OH- in aq solution.
What is the Bronsted-Lowry definition of an acid?
What is the Bronsted-Lowry definition of an base?
If the I.P is larger than the solubility product constant (Ksp), is the solution saturated. unsaturated or supersaturated?
I.P> Ksp supersaturated
If the I.P is smaller than the solubility product constant (Ksp), is the solution saturated. unsaturated or supersaturated?
If the I.P is equal than the solubility product constant (Ksp), is the solution saturated. unsaturated or supersaturated?
I.p = Ksp saturated
what is the common ion effect?
when a slightly soluble salt is added to a solution which already contains one of its components, the added salt is less soluble than if it were added to a pure solvent.
what is the name of the process for combing smaller nuclei into larger nuclei?
Fusion is the combining of smaller nuclei to create a larger nuclei.
what is nuclear fission?
splitting of atomic nuclei
Define reduction potential
tendency of species to acquire electrons.
Whats the formula for EMF
EMF= E red+ E ox
(T/F) When adding standard potentials, multiply by the number of moles oxidized or reduced first.
what is the formula for the standard free energy of an electrochemical cell?
ΔG= -(number of moles) (Faraday's constant)(EMF)
what is the relationship between EMF and Keq?
nFE= RT ln Keq
If the half life of an isotope is 2 years, how much of the original isotope will be left after 4 years?
What is the formula for exponential decay?
n=no e ^ -λt
what is mass defect?
difference between the mass of a nucleus and the sum total of its constituents (nucleons)
what formula is used for calculating binding energy?
Energy= (mass defect)(speed of light)^2
What is the oxidation number of free elements?
(T/F) Group IA elements usually have a +1 charge in a compound, and group IIA usually have a +2
what is the oxidation number of oxygen in most compounds?
What is the oxidation number of Group VIIA element in a compound?
except: if a group VIIA element is combined with and element with higher electronegativity, then the oxidation number is +1 or higher
what are the two types of electrochemical cells?
does oxidation occur at the anode or cathode?
does reduction occur at the anode or cathode?
which type of electrochemical cell generates energy?
Does a galvanic cell have a positive or negative ΔG?
what is the function of a salt bridge?
permits balancing of charge between cells
(T/F) A cell diagram adheres to the following conventions:
anode/anode solution// cathode solution/cathode
does an electrolytic cell have positive or negative ΔG?
positive= non- spontaneous
In which electrochemical cell is the anode positive?
In which electrochemical cell is the cathode positive?
what is faraday (F)?
F is equivalent to the amount of charge contained in one mole of electrons = 96,487 C.
(T/F) Electrons always flow from the anode to the cathode.
(T/F) An acid equivalent is equal to one mole of H+
Does high Ka correspond to weak or strong acid?
High Ka= strong acid
Does high Kb correspond to weak or strong acid?
High Kb= weak acid.
What is a polyprotic acid?
can lose more than one proton
ie: H2SO4 or H3PO4
what is an amphoteric species?
can act as acid or base
Strong acid + Strong base
pH of 7
Weak acid + Strong base
pH greater than 7
(T/F) A buffer solution consist of a mixture of a strong acid and its salt
buffer= mix of weak acid & its salt
What is the henderson-Hasselbalch equation for a weak acid buffer solution?
pH= pKa + Log (conjugate base)/(weak acid)
What is the Henderson-Hasselbalch equation for a weak base buffer solution?
pOH=pKb + log (conjugate acid)/(weak base)
Does the gain of electrons result in reduction or oxidation?
Does the loss of electrons result in reduction or oxidation?
(T/F) An oxidizing agent is oxidized in an electrochemical reaction.
what is a reducing agent?
species that loses electrons and thereby causes another agent to be reduced.
What is the lewis definition of an acid?
accepts electron pair
What is the lewis definition of an base?
donates electron pair
(T/F) All broasted-lowry acids are lewis acids.
what is the water dissociation constant @ 25 C? Kw=
What is the pH of a solution @ 25C with a pOH of 5?
pH= 14-pOH =9
What is the log formula for calculating pH?
pH= -log [H+]
What is the log formula for calculating pOH?
pOH= -log [OH-]
What is the pH of a 1 x 10^-14 M HCl solution?
would the pH of a 1.4 x 10^-14 M HCl solution be greater or less than 4?
less than 4
What is the product of a neutralization reaction?
will the titration of a weak acid with a strong base produce a slightly acidic or slightly basic solution?
will the titration of a strong acid with a strong base produce a slightly acidic or slightly basic or neutral solution?
will the titration of a strong acid with a weak base produce a slightly acidic or slightly basic solution?
(T/F) Solids and liquids are often referred to as the condensed phases.
What does it mean when two liquids are immiscible?
liquids repel each other and do not mix to form a solution.
What is an emulsion?
mix of immiscible liquids which are broken up into extremely small particles.
What is an amorphous solid?
no ordered 3D arrangement.
What are the two most common types of crystalline solids?
ionic & metallic
(T/F) A unit cell is a repeating unit of crystals
What is condensation?
Condensation: gas to liquid
Evaporation: liquid to gas
What is fusion?
solid to liquid
what is solidification (crystallization)?
liquid to solid
What is sublimation?
solid to gas
what is deposition?
gas to solid
(T/F) The rates at which two gases diffuse are inversely proportional to the square root of their molar masses.
what is effusion?
flow of gas particles under pressure from one container to another through a small opening.
(T/F) The rates of effusion for 2 molecules are directly proportional to the square root of their molar masses.
What is Dalton Law of Partial pressure?
the total pressure of a gaseous mix is equal to the sum pf partial pressure of the individual components.
What is the formula for calculating partial pressure?
PA= Pt XA ; XA= mol of A/ total mol
(T/F) A gas molecule's kinetic energy is inversely proportional to the absolute temp of the gas
Kinetic energy is directly proportional to the absolute temp.
Under what conditions is the ideal gas law most correct?
gases behave in a near-ideal fashion at low temp and high temp.
How do actual volume and predicted volume of a gas compare at moderately high pressures? Extremely high pressures?
Moderately high: gas volume less than would be predicted
Extremely high: gas volume more than would be predicted
How do actual volume and ideal volume of a gas compare at very low temp?
low temp: actual volume less than would be predicted.
What is the volume of 1 mole of gas at STP?
What are the typical units of density for a gas?
(T/F) For a specific sample of gas, (P1VA/T1)=(P2V2/T2)
What is the formula for calculating the density of a gas?
What is an aqueous solution?
one which water is the solvent
what is solubility?
measure of the amount of substance that can be dissolved in a particular solvent @ a particular temp
what is a saturated solution?
contains mx amount of solute that can be dissolved in a particular solvent @ a particular temp
Is osmotic pressure proportional to molarity?
What is the formula for osmotic pressure?
What is the formula for the vapor pressure of A in a solution of A and B?
PA= XA PA
What is a colligative property?
property derived sole from the number of particles present, not the nature of those particles.
Name the 4 colligative properties.
freezing point depression
boiling point elevation
vapor pressure lowering
What is the formula for freezing-point depression?