General Chemistry Flashcards
What are the bond orders of single, double, and triple bonds?
1st order, 2nd order, and 3rd order, respectively.
T/F, a triple bond is longer than a single bond?
False, a triple bond is shorter than a single bond
What is bond energy?
Bond energy is the amount of energy required to separate two bonded atoms.
Can both bonding and nonbonding electrons be valence electrons?
Yes, they can both be valence electrons. Nonbonding electrons are not involved in a bond.
Draw the lewis structure for HCN
H-C≡N:
What is the formula for calculating formal charge on an atom in a covalent bond?
Formal charge = V — (1/2 #bonding + #nonbonding)
What are resonance structures?
Two or more non-identical Lewis structures for the same molecule are resonance structures.
T/F, a lewis structure with small or no formal charges is preferred over one with large formal charges?
True
Should a negative formal charge be placed on highly electronegative atoms or weakly electronegative atoms?
Negative formal charge should be placed on highly electronegative atoms.
Which type of bond forms between atoms with small differences in electronegativity (0.4-1.7)?
A polar covalent bond forms between atoms with small differences in electronegativity.
Which type of bond forms between atoms with the same electronegativities?
A nonpolar covalent bond forms between atoms with the same electronegativities.
What is a coordinate covalent bond?
A coordinate covalent bond is one in which a pair of bonding electrons originates from just one of the atoms.
T/F, a dipole moment exists when a molecule has a separation of positive and negative charges?
True
What are the 3 steps for determining geometric configuration?
- Draw the lewis structure of the molecule 2. Count the bonding and nonbonding 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 the geometric arangements of CO2?
Linear
What is the geometric arangements of BH3?
Trigonal planar
What is the geometric arangements of NH3
Pyramidal
What is the geometric arangements of CH4?
Tetrahedral
PCl5
Trigonal bipyramidal
SF6
Octahedral
Can molecules with polar bonds be nonpolar?
Yes, if there is no net dipole moment within the molecule, it will be nonpolar.
What is the shape of an s orbital?
A s orbital is spherical
What is the shape of a p orbital?
A p orbital is bi-lobed
What are three types of intermolecular forces?
Three types of intermolecular forces are: a. dipole-dipole interactions b. hydrogen bonding c. dispersion forces
State the intermolecular forces in order of increasing strength?
Dispersion forces < dipole-dipole < hydrogen bonding
Which molecules, polar or nonpolar, typically have higher boiling points?
Polar molecules typically have higher boiling points
What is molar mass (molar weight)?
Molar mass is the number of grams per mole of a compound or an element
How many equivalents of hydrogen ion are in the following: HCl, H₂SO₄, H₂SO₄, H₃PO₄?
HCl = 1 equivalent H₂SO₄ = 2 equivalents H₂SO₄ = 3 equivalents H₃PO₄ = 3 equivalents
What is the formula for gram equivalent weight?
Gram Equivalent Weight = Molar Mass / n
What is the formula for calculating equivalents?
Equivalents = Weight of Compound / Gram Equivalent Weight
What is an empirical formula?
An empirical formula represents the simplest whole number ratio of the elements present in a compound
What is the empirical formula for C₆H₁₂O₆?
The empirical formula is CH₂O
What is a molecular formula?
A molecular formula represents the actual number of atoms of each element present in a molecule of the compound
What is the formula for calculating percent composition?
%Composition = (Mass of X in Compound / MW of Compound) x 100%
Classify the following reaction type: A + X →AX
Combination or addition
Classify the following reaction type: AX →A + X
Decomposition
Classify the following reaction type: AX + B →BX + A
Single displacement
Classify the following reaction type: AX + BY →AY + BX
Double displacement
Classify the following reaction type: HA(aq) + BOH(aq) →AB(aq) + H₂O
Neutralization
Zn(s) + CuSO4(aq) → Cu(s) + ZnSO4(aq) What is the net ionic equation for the above reaction?
Zn(s) + Cu^2+(aq) + SO4^2-(aq) ––> Cu(s) + Zn^2+(aq) + SO4^2-(aq)
Zn(s) + CuSO4(aq) → Cu(s) + ZnSO4(aq) What is the net ionic equation?
Zn(s) + Cu(²+)(aq) ➜ Cu(s) + Zn(²+)(aq)
Zn(s) + CuSO4(aq) → Cu(s) + ZnSO4(aq) Which of the above are spectator ions?
SO₄²- is a spectator ion
Balance the following equation: NF₃ + H₂O –––> HF + NO + NO₂
2NF₃ + 3H₂O –––> 6HF + NO + NO₂
What is a limiting reagent?
A limiting reagent is the reagent that is fully consumed in a reaction.
Given 1 mol of Ag and 0.4 mol of S, which is the excess reagent and how many moles will be left after the reaction is complete?
2Ag + S ––––> Ag₂S
What is theoretical yield?
Theoretical yield is the amount of product that can be predicted from a balanced equation.
What is actual yield?
Actual yield is the amount of product actually isolated from the reaction experimentally.
What is percent yield and what is the formula for calculating it?
Percent yield represents the relationship between actual yield and theoretical yield. Percent Yield = (Actual yield / Theoretical Yield) x 100%
What is an elementary reaction?
An elementary reaction is a reaction that cannot be decomposed into other reactions.
What is an intermediate?
An intermediate is a complex that appears during the course of a reaction but does no appear in the net reaction, or as a final product.
What is the rate determining step of a reaction?
The rate determining step is the slowest step of a reaction.
What is the general formula for the rate law of the following reaction? aA + bB ––––> cC + dD
Rate = k [A]^x [B]^y
T/F, Rate = -∆ [reactants] / time or Rate = ∆ [products] / time
True
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.
On a potential energy / Reaction coordinate diagram: What is the vertical difference from the product potential energy to the reactant potential energy?
∆H - Enthalpy change of a reaction is the difference between the potential energy of the products and the potential energy of the reactants.
On a potential energy / Reaction coordinate diagram: What is the vertical difference from the initial potential energy to the potential energy of the intermediate in the reaction?
Activation energy (Ea) for the forward reaction.
On a potential energy / Reaction coordinate diagram: What is the vertical difference between the intermediate potential energy to the product potential energy?
Activation energy (Ea) for the reverse reaction.
What is the enthalpy change of a reaction?
Enthalpy change (∆H) of a reaction is the difference between the potential energy of the products and the potential energy of the reactants.
How do increasing temperature and reactant concentration affect the rate of reaction?
Increasing temperature and reactant concentration increase the rate of most reactions.
Can the meduium in which a reaction takes place affect the reaction rate?
Yes, the medium can affect the reaction rate.
How does a catalyst increase reaction rate?
A catalyst increases the reaction rate by decreasing the Ea
What is the equalibrium constnat expression for the follwoing reaction? A + 3B –––> 2C + 2D
Keq = [C]² [D]² / [A] [B]³
Do pure solids or liquids appear in an equilibrium constant expression?
No, pure solids or liquids do not appear in an equilibrium constant expression.
Does Keq for a reaction remain constant at all temperatures?
No, Keq is characteristic of a given system at a given temperature.
If there is much more product than reactant at equilibrium, what can be said of Keq (as compared to 1)
Keq would be greater than 1.
If Keq is very small compared to 1, then what can be said about the amount of reactants and products at equilibrium?
If Keq is less than 1, there will be more reactants than products at equilibrium.
According to Le Chatelier’s Principle, in which direction will equilibrium shift if products are removed?
If products are removed, equilibrium will shift to favor the forward reaction.
How will increasing pressure affect the following reaction? N₂(g) + 3H₂(g) ←→2NH₃
Increasing the pressure will favor the forward reaction.
T/F, increasing the pressure of a system will shift equilibrium so as to increase the number of moles produced?
False, increasing pressure will shift equilibrium so as to produce fewer moles of gas.
How will decreasing temperature affect the following reaction? A ←→ B + heat
Decreasing temperature will favor the forward reaction.
How would increasing temperature affect the following reaction? A ←→ B + heat
Increasing temperature will favor the reverse reaction.
What is an isolated system?
An isolated system cannot exchange energy or matter with its surroundings.
What is a closed system?
A closed system can exchange energy but cannot 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?
An isothermal process is a process that occurs at a constant temperature.
What is an isobaric process?
An isobaric process is a process that takes place at a constant pressure.
What is an adiabatic process?
An adiabatic process is a process in 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?
True.
What is an endothermic process?
An endothermic process is a process that absorbs heat from the surroundings.
What is an exothermic process?
An exothermic process is a process that releases heat to the surroundings.
What is the formula for calculating ∆Hrxn?
q = (mass)(heat capacity)(∆ in Temperature) = mc∆T
Does a positive ∆H correspond to an endothermic or exothermic process?
A positive ∆H corresponds to an endothermic process.
Does a negative ∆H correspond to an endothermic or exothermic process?
A negative ∆H corresponds to an exothermic process.
What is standard heat of formation (∆Hºf)?
∆Hºf is the enthalpy change that occurs when one mole of a compound is formed from its elements in their standard states.
What is the ∆Hºf of an element in its standard state?
∆Hºf for an element in its standard state = 0
T/F, Hess’s Law states that enthalpies of reactions are additive?
True.
If the ∆H of a forward reaction is -220 kj/mol, what is the ∆H of the reverse reaction?
The ∆H of the reverse reaction is +220 kJ/mol
What is bond dissociation energy?
Bond dissociation energy is the amount of energy required to break a particular bond in one mole of gaseous molecules.
What is entropy?
Entropy is the measure of disorder or randomness of a system.
When does a system reach maximum entropy?
Maximum entropy occurs when a system is at equilibrium.
What is the Gibb’s Free Energy equation? ∆G =
∆G = ∆H – T∆S
How does the value of ∆G correlate with the spontaneity of a reaction?
∆G is negative for a spontaneous reaction. ∆G is positive for a non-spontaneous reaction.
What is the value of ∆G for a system at equilibrium?
∆G at equilibrium = 0
T/F, a reaction with (+) ∆H and a (–) ∆S is always spontaneous.
False, a reaction with a (+) ∆H and a (–) ∆S is always non-spontaneous.
Under what conditions will a reaction with a (+) ∆H and a (+) ∆S be spontaneous?
At high temperature, a reaction with a (+) ∆H and a (+) ∆S will be spontaneous.
Under what conditions will a reaction with a (–) ∆H and a (–) ∆S be spontaneous?
A low temperature, a reaction with a (–) ∆H and a (–) ∆S will be spontaneous.
What is standard free energy, ∆Gº?
∆Gº is the ∆G of a process occurring at 25ºC, 1 atm of pressure, and when the concentrations of all reactants and products are 1M.
What is standard free energy of formation, ∆Gºf?
∆Gºf is the free energy change that occurs when 1 mole of a compound in its standard state is formed from its elements in their standard states under standard conditions.
What is the formula relating ∆Gº to Keq? ∆Gº=
∆Gº = –RT lnKeq
T/F, once a reaction comences: ∆G = ∆Gº + RTlnQ
True.
What are the three phases of matter?
The three phases of matter are: solid, liquid, and gas.
What is standard pressure in atm, mm Hg, and torr?
Standard pressure = 1 atm = 760 mm Hg = 760 torr.
T/F, an ideal gas represents a hypothetical gas whose particles take up no volume and eperience no intermolecular forces.
True.
What is standard temperature in Kelin? Celcius?
Standard temperature = 273.15 k = 0ºC
What is Boyle’s Law?
Boyle’s Law states that under isothermal conditions, pressure is inversely proportional to volume. P₁V₁ = P₂V₂
What is Charles Law?
Charles Law states that under constant pressure, volume is directly proportional to absolute temperature. V₁/T₁ = V₂/T₂
What is the ideal gas law?
(pressure)(volume) = (moles)(gas constant)(temperature) PV = nRT
T/F, Avogadro’s Principle states that at constant temperature and pressure, volume is directly proportional to the number of moles of gas.
True.
What is the volume of 1 mole of gas at STP?
1 mole of gas occupies 22.4 liters at STP.
What are the typical units of density (for a gas)?
The density units are g/L.
T/F, for a specific sample of gas, P₁V₁ / T₁ = P₂V₂ / T₂
True.
What is the formula for calculating the density of a gas? d =
d = m/v = P(MM) / RT
Under what conditions is the ideal gas law most correct?
Gases behave in a near-ideal fashion at low pressures and high temperatures.
How do actual volume and predicted volume of a gas compare at moderatly high pressures? Extrememly high pressures?
At moderately high pressures, a gas’s volume is less than would be predicted. At extremely high pressures, a gas’s volume is more than would be predicted.
How do actual volume and ideal volume of a gas compare at very low temperatures?
At very low temperatures, actual volume is less than would be predicted.
What is Dalton’s Law of partial pressures?
Dalton’s Law of Partial Pressures states that the total pressure of a gaseous mixture is equal to the sum of the partial pressures of the individual components.
What is the formula for calculating partial pressure? PA =
PA = (PT)(XA) ; XA = mole of A / total mol
Given a mixture of 2 gases (O₂ and N₂) at STP and occupying 22.4L. If there are 0.75 moles of N₂, how many moles of O₂ are there?
0.25 moles of O₂. (1 mole occupies 22.4L at STP)
T/F, a gas molecule’s kinetic energy is inversely proportional to the absolute temperature of the gas?
False, kinetic energy is directly proportional to absolute temperature.
T/F, the rates at which two gases diffuse are inversely proportional to the square root of their molar masses?
True.
What is effusion?
Effusion is the flow of gas particles under pressure from one container to another through a small opening.
T/F, the rates of efusion for two molecules are directly proportional to the square root of their molar masses?
False, the rates of effusion are inversely proportional, just as in diffusion.
T/F, solid and liquids are often referred to as the condensed phases?
True.
What does it mean when two liquids are immiscible?
Immiscible liquids repel each other and do not mix to form a solution.
What is an emulsion?
An emulsion is a mixture of immiscible liquids which are broken up into extremely small particles.
What is condesation?
Condensation occurs when gas changes to liquid.
What is Evaporation?
Evaporation occurs when liquid changes to gas.
What is fusion?
Fusion occurs when a solid changes to a liquid.
What is solidification (crystallization)?
Solidification of crystallization occurs when a liquid changes to a solid.
What is sublimation?
Sublimation occurs when a solid changes directly to a gas.
What is deposition?
Deposition occurs when a gas changes directly to a solid.
On a pressure / temperature graph, what is the far left/upper area represent?
The far left/upper region represents solid phase.
On a pressure / temperature graph, what is the middle/upper region represent?
The middle/upper region represents liquid phase.
On a pressure / temperature graph, what is the far right/lower region represent?
The far right/lower region represents the gas phase.
On a pressure / temperature graph, what is the point inbetween the solid phase, liquid phase and gas phase region represent?
The point where all phases meet is called the triple point. All three phases exist simultaneously at this point.
On a pressure / temperature graph, what is the transition from the far left/upper to the middle/upper region represent?
Fusion, or melting.
On a pressure / temperature graph, what is the transition from the far left/upper to the far right/lower region represent?
Sublimation
On a pressure / temperature graph, what is the transition from the middle/upper to the far left/upper region represent?
Freezing, crystallization, or solidification.
On a pressure / temperature graph, what is the transition from the middle/upper to the far right/lower region represent?
Evaporation, boiling, or vaporization.
On a pressure / temperature graph, what is the transition from the far right/lower to the far left/upper region represent?
Deposition.
On a pressure / temperature graph, what is the transition from the far right/lower to the middle/upper region represent?
Condensation.
What is a colligative property?
A colligative property is a property derived solely from the number of particles present, not the nature of those particles.
Name four colligative properties?
Freezing-point depression, boiling-point elevation, osmotic pressure, and vapor pressure lowering.
What is the formula for freezing-point depression? ∆Tf =
∆Tf = Kf (molality of solution) = (Kf)(m)
What is the formula for boiling-point elevation? ∆Tb =
∆Tb = Kb (molality of solution) = (Kb)(m)
Is osmotic pressure proportional to molarity?
Yes, osmotic pressure is proportional to molarity.
What is the formula for osmotic pressure? Π =
Π = (Molarity)(Gas constant)(Temperature) = MRT
What is the formula for the vapor pressure of A in a solution of A and B? PA =
PA = (mole fraction of A)(PºA) = (XA)(PºA)
What is an aqueous solution?
An aqueous solution is one in which water (H2O) is the solvent.
What is solubility?
Solubility is the measure of the amount of substance that can be dissolved in a particular solvent at a particular temperature.
What is a saturated solution?
A saturated solution contains the maximum amount of solute that can be dissolved in a particular solvent at a particular temperature.
Name this ion? Cu+
Copper (I) or Cuprous
Name this ion? Cu²+
Copper (II) or Cupric
Name this ion? H-
Hydride
Name this ion? ClO-
Hypochlorite
Name this ion? ClO₂-
Chlorite
Name this ion? ClO₃-
Chlorate
Name this ion? ClO₄-
Perchlorate
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 form negatively-charged ions?
True.
What is an electrolyte?
An electrolyte is a 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 defintion of mole fraction (X)?
X = (moles of compound) / (total number of moles)
What is the definition of molarity (M)?
M = (moles of solute) / (liters of solution)
What is the definition of molality (m)?
m = (moles of solute) / (Kg of solvent)
What is the definition of normality (N)?
N = (GEW of solute) / (liters of solution)
T/F, a solution which is diluted is related to its initial concentration as follows: MiVi = MfVf
True.
Fe(OH)₃ (s) ←→Fe³+ (aq) + 3OH- (aq) What is the ion product (I.P.) for the above reaction?
I.P. = [Fe³+][OH-]³
Fe(OH)₃ (s) ←→Fe³+ (aq) + 3OH- (aq) What is the solubility product constant (Ksp) for the above reaction?
Ksp = [Fe³+]sat[OH-]³sat
Fe(OH)₃ (s) ←→Fe³+ (aq) + 3OH- (aq) 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.
If the ion product (I.P.) is larger than the solubility product constant (Ksp), is the solution saturated, unsaturated, or supersatureated?
If I.P. > Ksp, then the solution is supersaturated.
If the I.P. is smaller than the Ksp, is the solution saturated, unsaturated, or supersaturated?
If I.P. < Ksp, then the solution is unsaturated.
If the I.P. is equal to the Ksp, is the solution saturated, unsaturated, or supersaturated?
If I.P. = Ksp, then the solution is saturated.
What is the comon 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 Bronsted-Lowry definition of an acid?
The bronsted-Lowery theory defines an acid as a species that donates protons.
What is the Bronsted-Lowry definition of a base?
The Bronsted-Lowry theory defines a base as a species that accepts protons.
HNO₂ (aq) + H₂O ←→ NO₂- (aq) + H₃O+ Which of the above molecule(s) is/are the conjugate acid?
HNO₂ is the conjugate acid and NO₂- is its conjugate base.
HNO₂ (aq) + H₂O ←→ NO₂- (aq) + H₃O+ Which of the above molecule(s) is/are the conjugate base?
H₃O+ is the conjugate acid of its conjugate base H₂O.
What is the Lewis definition of an acid?
A lewis acid is a species that accepts an electron pair.
What is the Lewis definition of a base?
A lewis base is a species that donates an electron pair.
T/F, all bronsted-lowry acids are lewis acids?
True.
Name this acid: HF
Hydrofluoric acid.
Name this acid: HClO₄
Perchloric acid.
Name this acid: HNO₂
Nitrous acid.
Name this acid: HNO₃
Nitric acid.
At 25ºC, pH + pOH =
pH + pOH = 14
What is the water dissociation constant at 25ºC? Kw =
Kw = [H+] [OH-] = 1 x 10^-14
Is a solution with a pH of 4 acidic or basic?
A pH of 4 corresponds to an acidic solution.
Is a solution with a pOH of 4 acidic or basic?
A pOH of 4 (pH = 10) corresponds to a basic solution.
What is the pH of a solution at 25ºC with a pOH of 5?
pH = 14 – pOH = 9
What is the logarithmic formula for calculating pH?
pH = –log [H+]
What is the logarithmic formula for calculating pOH?
pOH = –log [OH-]
What is the pH of a 1 x 10^-4 M HCl solution?
pH = 4
Would the pH of a 1.4 x 10^-4 M HCL solution be greater than 4 or less than 4?
The pH would be less than 4.
HCO₃- (aq) ←→ H+ (aq) + CO₃-² What is the Ka for HCO3-?
Ka = [H+][CO₃²-] / [HCO₃-]
HCO₃- (aq) ←→ H+ (aq) + CO₃-² What is the Kb for CO₃²- ?
Kb = [HCO₃-] [OH-] / [CO₃²-]
For a conjugate acid-base pair at 25ºC, Ka x Kb =
Ka x Kb = 1 x 10-¹⁴
What is the conjugate acid of CO₃²- ?
The conjugate acid of CO₃²- is HCO₃-
What would Kb equal if Ka = 1x10-6?
Kb = 1x10-8
What would Ka equal if Kb = 1x10-3?
Ka = 1x10-11
T/F, an acid equivalent is equal to one mole of H+?
True
Does a high Ka correspond to a weak acid or a strong acid?
A high Ka corresponds to a strong acid.
Does a high Pka correspond to a weak acid or a strong acid?
A high Pka corresponds to a weak acid.
What is a polyprotic acid?
A polyprotic acid can lose more than one proton, e.g., H2SO4 or H3PO4
What is an amphoteric species?
An amphoteric species can act as both an acid and a base
Would the pH of the equivalence point for the following titrations be equal to 7, greater than 7, or less than 7?
Strong acid + strong base yield a pH of:
Strong acid + strong base = pH of 7
Would the pH of the equivalence point for the following titrations be equal to 7, greater than 7, or less than 7?
Weak acid + strong base yield a pH of:
Weak acid + strong base = pH greater than 7
- b
- c
- a
- d
T/F, a buffer solution consists of a mixture of a strong acid and its salt?
False, a buffer solution consists of a mixture of a weak acid and its salt or a weak base ant its salt.
What is the Henderson-Hasselbalch equation for a weak acid buffer solution?
pH = pKa + log [conj 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?
The gain of electrons results in reduction. OIL RIG = Oxidation Is Loss, Reduction Is Gain
Does the loss of electrons result in the reduction or oxidation?
The loss of electrons results in oxidation.
T/F, an oxidizing agent is oxidized in an electrochemical reaction?
False, an oxidizing agent is a species that gains electrons and thereby causes another agent to be oxidized.
What is a reducing agent?
A reducing agent is a species that loses electrons an thereby causes another agent to be reduced.
What is the oxidation number of free elements (i.e., He, H₂, N₂, etc.)?
The oxidation number of free elements is zero.
T/F, Group IA elements usually have a +1 charge in a compound, and Group IIA usually have a +2?
True.
What is the oxidation number of oxygen in most compounds?
Oxygen typically has an oxidation number of -2.
What is the oxidation number of a Group VIIA element in a compound?
Group VIIA elements have a -1 oxidation number. EXCEPTION: If a group VIIA element is combined with an element with a higher electronegativity, then the oxidation number is +1 or higher.
What are the two types of electrochemical cells?
The two types of electrochemical cells are: galvanic (or voltaic) and electrolytic.
Does oxidation occur at the anode or cathode?
Oxidation occurs at the anode. An Ox / Red Cat = Anode Oxidation / Reduction Cathode
Does reduction occur at the anode or cathode?
Reduction occurs at the cathode.
Which type of electrochemical cell generates energy?
A galvanic cell supplies energy.
Does a galvanic cell have a positive or negative ∆G?
A galvanic cell has a negative ∆G and is therefore spontaneous.
What is the function of a salt bridge?
A salt bridge permits the balancing of change between the cells.
T/F, a cell diagram adheres to the following conventions: anode | anode solution || cathode solution | cathode
True.
Does an electrolytic cell have a positive or negative ∆G?
An electrolytic cell has a positive ∆G and is therefore non-spontaneous.
In which electrochemical cell is the anode positive?
An electrolytic cell has a positive anode.
In which electrochemical cell is the cathode positive?
A galvanic cell has a positive cathode.
What is a farady (F)?
A Faraday (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?
True.
Define reduction potential.
Reduction potential is defined as the tendency of a species to acquire electrons.
Ag+ + e- –––> Ag (s) Eº = +0.80V Tl+ + e- –––> Tl (s) Eº = -0.34V Which of the above species will be reduced most easily?
Ag+ will be reduced most easily because it has a higher reduction potential.
Ag+ + e- –––> Ag (s) Eº = +0.80V Tl+ + e- –––> Tl (s) Eº = -0.34V Which of the above species will be oxidized most easily?
Tl will be oxidized most easily.
Ag+ + e- –––> Ag (s) Eº = +0.80V Tl+ + e- –––> Tl (s) Eº = -0.34V What is the EMF for a Tl and Ag galvanic cell?
EMF = Eºred + Eºox = 0.8 + 0.34 = 1.14V
T/F, when adding standard potentials, multiply by the number of moles oxidized or reduced first?
False, never multiply by the number of moles when adding standard potential.
What is the formula for the standard free energy of an electrochemical cell? ∆Gº =
∆Gº = –(number of moles)(Faraday’s constant)(EMF) = –nFEºcell
What is the relationship between EMF and Keq?
nFEºcell = RT lnKeq
How many protons, neutrons, and electrons are in: ²⁴₁₂Mg ?
12 Protons 12 Neutrons 12 Electrons
How many protons, neutrons and electrons in: ⁶³₂₉Cu ²+ ?
29 Protons 34 Neutrons 27 Electrons
How many protons, neutrons and electrons are in: ³⁵₁₇Cl- ?
17 Protons 18 Neutrons 18 Electrons
What are valence electrons?
The electrons farthest from the nucleus, as well as any electrons available for bonding, are the valence electrons.
T/F, one amu is equal to 1/12 the mass of a carbon-12 atom?
True.
How many particles are in a mole (mol)?
1 mol = 6.022 x 10²³
What is atomic weight?
The atomic weight of an element reflects the number of grams per mole (g/mol) 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?
An isotope is a different form of the same element due to a different number of neutrons.
How many more protons are in a carbon-14 atom than in a carbon-12 atom?
None. Carbon-12 and Carbon-14 are isotopes. They thus have the same number of protons.
What is an atomic emission spectrum?
An atomic emission spectrum is the unique spectrum of light emitted when an atom’s electrons fall to their ground states.
What is an atomic absorption spectrum?
A atomic absorption spectrum is the unique spectrum of light absorbed when an atom’s electrons are excited to higher energy levels.
Define the Heisenberg uncertainty principle.
The Heisenberg uncertainty principle states that it is impossible to know both the momentum and position of an electron at the same time.
Define the Paui exclusion principle.
The Pauli exclusion principle states that no two electrons in an atom can have the same four quantum numbers.
What does the principal (1st) quantum number (n) represent?
The principal (1st) quantum number (n) is an integer which represents the shell (energy level) of an electron.
What is the maximum number of electrons allowed in the second shell (n = 2)
The maximum number of electrons in the second shell is eight. (The maximum number of electrons in any shell equals 2n².)
What does the azimuthal (2nd) quantum number (l) represent?
The azimuthal (2nd) quantum number (l) represents the subshell.
What are the first four subshells (corresponding to l = 0, 1, 2 and 3)?
The first four subshells are: s, p, d and f
What is the formula for the maximum number of electrons allowed in a subshell?
Maximum number of electrons in a subshell = (4l + 2).
What does the magnetic (3rd) quantum number (m”l”) represent?
The third quantum number (m”l”) represents an orbital within a subshell. The possible values range from “-l” to “l”.
How many orbitals can each subshell acommodate?
The number of orbitals in each subshell are all integers from “l” to “-l”. Therefore: s 0 = 1 p –1, 0, 1 = 3 d –2, –1, 0, 1, 2 = 5 f –3, –2, –1, 0, 1, 2, 3 = 7
How many fourth quantum numbers (ms) are possible for an electron? what are they?
The two possible values for ms are +1/2 and -1/2.
What is Hund’s Rule?
Hund’s Rule states that electrons will fill to create the maximum number of half-filled orbitals.
Which subshell will fill first? 5s or 3d?
3d will fill before 5s.
Which subshell will fill first? 6s or 4f?
6s will fill before 4f.
Which subshell will fill first? 4p or 3d?
3d will fill before 4p.
What is another way to determine which subshell will fill first without drawing the fill diagram?
Compare (n+ “l”) values. The lower the sum has lower energy. If the sums are equal, the subshell with the lower n value will fill first.
What is paramagnetic material?
A paramagnetic material has unpaired electrons.
What is a diamagnetic material?
A diamagnetic material has no unpaired electrons.
Does a “period” run horizontally or vertically?
A period runs horizontally.
Does a “group” run horizontally or vertically?
A group runs vertically.
T/F, groups have the same valence configuration and have similar chemical properties?
True.
Which group (A or B) contains the representative elements?
Group A elements are the representative elements.
What is the valence configuration for an element in Group VA?
s²p³
What is the valence configuration for an element in Group IIIA?
s²p¹
What is the valence configuration for an element in group VIIIA?
s²p⁶
What is the valence configuration for an element in group VB?
s²d³
What is the valence configuration for an element in group VIB?
s¹d⁵
Which group of elements (A or B) contains the transition elements?
Group B elements are the transition elements.
What happens to the nmber of electrons when one moves from left to right across a row?
Electrons are sequentially added as you move across a row.
Are electrons more tightly held or less tightly held as one moves down a column?
Electrons are less tightly held as you move down a column.
What is the atomic radii trend within the periodic table?
Atomic radii decrease as you move from left to right across a period and up a group.
What is ionization energy (I.E.)?
Ionization energy is the energy required to completely remove an electron from an atom.
What is the ionization energy trend within the periodic table?
I.E. increases as you move from left to right across a period and up a group.
Compare the value of the first ionization and second ionization energy of an atom.
The second ionization energy is always higher than the first ionization energy of an atom.
What is electron affinity?
Electron affinity is the energy released when an atom accepts an electron.
What is the elctron affinity trend within the periodic table?
Electron affinity increases as you move from left to right acros a period and up a group.
T/F, group VIIIA elements have high electron affinities.
False, Group VIIIA elements have a stable octet and have an electron affinity approaching zero.
What is electronegativity?
Electronegativity is a measure of the attraction of an atom has for electrons in a chemical bond.
What is the electronegative trend within the periodic table?
Electronegativity increases as you move from left to right across a period and up a group.
T/F, metals are found on the left side of the periodic table and are good conductors of electricity and heat?
True.
T/F, Nonmetals are found in the middle of the periodic table and are malleable, ductil, and shiny?
False, nonmetals are generally brittle and lusterless, and are located on the upper right side of the periodic table.
T/F, metalloids are found between the metals and nonmetals and have varying properties.
True.
Which group of elements contains the alkali metals?
Group IA elements are known as the alkali metals.
which group of elements contains the halogens?
The halogens are in group VIIA.
Which group of elements contains the alkaline earths?
The alkaline earths are in group IIA.
Which group of elements contains the noble gases?
The noble gases are in group VIIIA.
Which groups of elements contain the transition metals?
The transition metals are in groups IB to VIIIB.
What is an ionic bond?
An ionic bond is formed from the transfer of electrons between two atoms.
What is a covalent bond?
A covalent bond is formed from sharing of electrons between atoms.
What is a polar covalent bond?
A polar covalent bond is one that has properties of both ionic and covalent bonds. Electrons are shared, but not equally.
What is a cation?
A cation is a positively-charged ion.
What is an anion?
An anion is a negatively-charged ion.
Which type of bond forms between two atoms with substantial differences in electronegativities (>1.7)?
Ionic bonds form between two atoms with substantial differences in electronegativities.
T/F, all atoms bond according to the “octet rule”?
False, some atoms such as hydrogen can have only two valence electrons while other can have more than eight.
What are some characteristics of ionic compounds?
Ionic compounds form crystal lattices, conduct electricity in solution, and have high melting and boiling points.
