CHEM 1133 Ch. 20.1 – Flashcards

Unlock all answers in this set

Unlock answers
question
Spontaneous change
answer
A chemical or physical change that occurs by itself under specified conditions without a continuous input of energy from outside the system
question
Non-spontaneous change
answer
A physical or chemical change that occurs only if the surrounding supplies the system with a continuous input of energy.
question
The second law of thermodynamics
answer
All real processes occur spontaneously in the direction that increases the entropy of the universe.
question
The third law of thermodynamics
answer
A perfect crystal has zero entropy at a temperature of absolute zero.
question
Prediction of relative S° values of a system
answer

 

  1. S° increases as temperature increases
  2. S° increases as a substance changes from solid to liquid to gas 
  3. S° of a dissolved solid or liquid is greater than the S° of the pure solute. This is not necessarily the case for ionic solutions since the water molecules may inhibit ions from an increased microstate. 
  4. The S° of a gas decreases when it dissolves in an aqueous solution. The entropy of a gas increases however when dissolved in another gas due to the separation and mixing of gas molecules. 
  5. Heavier molecules have larger S° values.
  6. For allotropes the entropy is higher for for more atoms that allow more freedom of motion.
  7.  S° increases with chemical complexity.
  8. The physical state of a compound dominates the complexity.

 

 

question
Solubility
answer
The maximum amount of solute that can dissolve in a given volume of solvent @ a given temperature. 
question
Molar solubility 
answer
Number of moles of solid dissolved per liter liter of solution
question
The common ion effect
answer
The solubility of a salt is less in the presence of a common ion already present in the solution as is predicted in Le Cheatliers principle.   
question
How to find pH at which a medal hydroxide ionic solution precipitates:
answer

  1. Write the Ksp equation for the ions based on their coefficients when dissolved.
  2. Locate the Ksp value and set it equal to ionic equation.
  3. Plug in molarity of medal ion. 
  4. Solve for hydroxide ion.

question
How to find the molarity of an ionic medal in a medal hydroxide ionic solution given the solutions pH:
answer

  1. Write out the Ksp equation.
  2. Find concentration of OH- via 14-pH=pOH, 10-pOH=[OH-].
  3. Determine Ksp (given in appendix).
  4. Solve for ionic medal.

question
How to find the percent ionic medal left in a solution after its concentration has been changed (for example due to precipitation by addition of pH etc.):
answer

Percent concentration left in solution:

[(Current concentration)/(initial concentration)](100)

question
Formation constant:
answer
The equilibrium constant for the one step formation of a complex ion from a metal ion and its ligands.
question
Coordinate covalent bond:
answer
A bond between two atoms in which one atom contributes both electrons.
question
Saturated
answer
When the maximum amount of solute has been dissolved the solution is saturated.
question
Supersaturated
answer
An unstable solution with more solute dissolved compared to normal levels of saturation.
question
Insoluble
answer
A substance that won't dissolve in a solution.;
question
Solubility product constant (Ksp)
answer

The equilibrium constant for a solid dissolving into ions.

;

Ksp = products/reactants

;

Since reactants are solids and solids are not included in equilibrium calculations there is no denominator and on products are multiplied and raised by their coefficient.

question
Situation where Ksp's of salts cannot be compared to determine which is more soluble
answer
In cases where the stoichiometry is not 1/1. 
question
Crystal field theory
answer
A theory developed to explain the character in color and magnetism of complex ions by explaining the effect the d orbital influence on the ligands.
question
Crystal field splitting energy (?)
answer
The magnitude of splitting of the d orbital affected by the binding of ligands to a metal ion.
question
Strong field ligands vs. weak field ligands
answer
Stronger field ligands cause a larger split of the d orbital when creating a complex ion with the metal ion.
question

High spin vs. low spin complexes

answer

High spin complexes: created by weak crystal fields, such complex ions contain the least amount of unpaired electrons.

 

Low spin complexes: created by strong crystal fields, such complex ions contain the maximum amount of unpaired electrons.

question
Chemical kinetics
answer
The study of reaction rates, the changes in concentrations of reactants (or products) as a function of time. 
question
Four factors that affect the rate of a given reaction
answer

  1. Concentration of reactants: the more frequently reactants collide the faster a reaction occurs; therefore, an increase in concentration will increase the number of collisions between reactants which will increase the rate of the reaction.
  2. Physical state of reactants: the more exposed reactants are to one another the faster the reaction due to a higher number of collisions. For example, wood chips burn faster than a wooden log because there is more surface area exposed in the mulch. 
  3. Temperature of environment: increasing temperature increases the number of collisions between reactants; however, more importantly, increased temperature increases the kinetic energy of the molecules that collide. Kinetic energy is of significant importance because reaction are dependent on kinetic energy. If the kinetic energy of a collision is not adequate, chemical reactions between reactants may not occur.
  4. The use of a catalyst.

question

Reaction rate

answer
The changes in concentrations of reactants or products per unit time.
question
Instantaneous rate
answer
The rate at a particular instant in a reaction.
question
Initial rate
answer
The instantaneous rate of a reaction at the moment the reactants mix.
question
The rate law (rate equation)
answer

The rate law expresses the rate as a function of reactant concentrations, product concentrations , and temperature. The components of the rate equation include the rate constant and the reaction order. The rate law is deduced by calculating the initial rate of a reaction, using initial rates from several experiments to find the reaction orders, using the values obtained from the initial rate and and reaction order to find the rate constant. 

question
The rate constant
answer

A constant specific for a given reaction and is not changed by the stage in the reaction.

question

Reaction orders

answer

Define how the rate is affected by reactant concentration. The reaction orders are not derived from a reactions stoichometry (coefficients) but from rate data. Reaction orders cannot be negative or fractions; they are zero or positive integers. 

question
Three ways to determine the initial concentration rate
answer

  1. A change in color due to the production or elimination of color.
  2. A change in pressure if there is an increase or decrease in gaseous moles of a substance. 
  3. A change in conductivity when a reactions conductivity changes as it proceeds.

question
Transition metals with electron configuration exceptions:
answer

  1. Cu: [Ar]4s13d10

question
How to predict the effect of solubility by the introduction of acid
answer
  1. If the precipatite produces hydroxide (when in aqueous form) than the hydroxide will react with the hydronium to produce water. The reaction will proceed to the right (more precipitate will dissolve) because solute evolved into water.
  2. If a component of the of the precipitate is a weak base in aqueous form than the weak base will react with hydronium to form water. The reaction will proceed to the right as more product evolved (more precipitate will dissolve).
  3. If the dissolved precipitate is not a weak base (eg. strong base) the reaction will not be effected when hydronium is dissolved.
question
How to caluclate the solubility of a precipitate when given Ksp
answer
  1. Write out the reaction when the precipitate dissolves.
  2. Write the Ksp equation
    • Treat coffecients by multiplying and raising to the power by the coefficient.
    • Let solute components equal S.
  3. Solve for S (solubility).

 

question
How to solve for solubility given a precipitates Ksp and an initial concentration of one of the solutes (the common ion effect)
answer
  1. Write out the solubility.
  2. Set up a reaction table with S as unknown and ion already present added to unknown.
  3. Find theoretical concentrations at equilibrium.
  4. Solve for S (solubility).
question
Find Ksp given solubility values
answer
  1. Convert solubility to molar solubility.
  2. Write out reaction table based on coefficients.
  3. plug into Ksp (Ksp = [2A]^2[B]) reaction equation.
  4. Solve for Ksp.
question
Complex ion
answer
A central metal ion covalently bonded to two or more anions or molecules.
question
Ligands
answer
The anions or neutral molecules bonded to an ionic metal in a complex.
question
Integrals of the 1st 2nd and 3rd order
answer

  1. First order integral: x
  2. Second order integral: ln(x)
  3. Third order integral: 1/x

question
Solubility rules
answer

  1. Soluble:
    1. Group 1 alkali metals are soluble.
    2. Ammonia (NH4) is soluble.
    3. Nitrates, acetates, and chlorates are soluble.
    4. Br, Cl, F, and I are soluble except when mixed with Ag, Pb, Cu, and Hg.
    5. All sulfates (SO4) are soluble except when Ba, Sr, Ca, Ag, and Pb.
  2. Insoluble compounds:
    1. All Hydroxides are insoluble except when bonded to group 1 metals or large group two metals (Ca and bigger).
    2. Phosphates, carbonates are insoluble except when bonded with group 1 metals and NH4. 
    3. Sulfides are insoluble except when bonded to group 1, 2 metals, or NH4. 
  3. Remember:
    1. The larger the charge of the ions in an ionic compound, the less soluble the compound.
    2. Cues for soluble compounds: group 1 metals, 2 metals, NH4, nitrate, and sulfate, halogens (Br, I, Cl, F), acetates, perchlorates.
    3. Insoluble: Hydroxides, carbonate, phosphate, sulfide, Pb, Ag, Cu, Hg.

question
Classifying acids and bases (strong vs. weak)
answer

  1. Strong acids:
    1. Halogens HBr, HCl, HI (excluding HF which is weak).
    2. Oxoacids: 2 or more oxygens than hydrogens (H2SO4, HNO3, HPO3, HClO4). 
  2. Weak acids:
    1. Acids where the hydrogen is not bonded to the oxygen.
    2. Oxoacids with 1 oxygens/ 1 hydrogen ratio.
    3. Carboxylic  acids.
  3. Strong bases:
    1. Hydroxide compounds.
    2. Compounds containing oxygen with a negative two charge.
  4. Weak bases:
    1. Compounds with electron rich nitrogens (example: NH3 (ammonia) and amines.

question
First integrated law
answer
ln([A]0/[A])t = kt
question
Fraction of reactant decomposed in a RxN with concentration change over time
answer

([A]0-[A]t)/[A]0

 

question
Half life
answer
The time required for a reactant's concentration to reach half its initial value.
question
The time it takes to reach one half life
answer
t=ln(2)/k
question
Half life of a first order reaction
answer
t(1/2)=ln(2)/k
question
Half life of a second order reaction
answer
t(1/2)=1/(k[A]0)
question
Half life of a zeroth order reaction
answer
t(1/2)=[A]0/(2k)
question
Activation energy
answer
The minimum energy molecules must have to react.
question
Arrhenius equation
answer

k=Ae^-(Ea/RT)

;

Ea/RT: gives the number of molecules at a given temperature that will have enough energy to react.;

;

A: the "pre-exponential factor"and accounts for the fact that some molecules won't form products upon interaction (for example incorrect orientation upon collision). The pre-exponential symbol expresses the number of molecules that receive an adequate amount of activation energy but do not proceed the hump to and evolve into products. 

question
Collision theory 
answer
The collision theory claims that reactant particles, atoms, molecules, and ions, must collide in order to react.
question
Radioactivity - Ch. 23.1
answer

Decay, of an unstable nucleus, by emitting radiation.

question

Nucleons (23.1)

answer
Elementary particles, the protons and neutrons, that make up the nucleus.
question
(23.1) Nuclide
answer

A nuclear with a specific number of two types of nucleons. When an element has two isotopes, each isotope is a unique number of neutrons but the same number of protons. 

question
Isotopes
answer

Atoms with a characteristic number of protons but a different number f neutrons. 

question
Chemical changes vs. nuclear reactions
answer

  1. Electrons involved in chemical reactions vs. protons, neutrons and subatomic particles involved in nuclear reactions.
  2. In chemical reactions substances are changed; in nuclear reactions atoms are changed.
  3. Chemical reactions are accompanied by relatively small changes in energy vs. nuclear reactions are accompanied by relatively large quantities of energy.
  4. Chemical reaction rates are influenced by temperature, catalysts, concentration, and the compound at hand. Nuclear reaction rates are influenced mainly by the number of nuclei and only on rare occasions by element/compound at hand. 

question
(18.2) Number of of sigfigs
answer
The number of sig figs in a concentration equals the number of sigfigs to the right of a pH/pOH decimal.
question
(18.1) Arrhenius acid - base definition
answer

  • An acid is any substance that has H+ ions in it yields hydronium in water.
  • A base is a substance that has OH in its formula and dissociates in water yields OH. 

question
(18.1) Neutralization
answer
When H ions and OH ions combine to form H2O.
question
(18.2) Comparison of hydronium in different solutions
answer
a pH of one is 10 times stronger than a pH of 2 and 100 times stronger than a pH of 3. 
question
(18.2) The relations among pH, pOH, and pKw
answer

Kw = [H30+][OH-] = 1e-14

 

pKw = pH+pOH = 14

 

 

question
(18.2) Acid base definition of Arrhenius vs. Bronstead lowry vs. lewis
answer

Arrhenius acid base definition: an acid is any molecule that contains a hydrogen ion and dissociates ions into H+ in aqueous solutions. A base is any compound containing a OH- complex that dissociates into OH- ions when in aqueous solution.

 

Bronstead lowry definition: An arrhenius and Bronstead lowry acid are the same. A Bronstead Lowry base accepts H+ in aqueous solutions and other situations.

 

Lewis acid base definition: An acid is any compound that donates accepts a lone pair of electrons. A base is any compound that donates a pair of lone electrons. 

question
(18.3) Conjugate acid base pairs
answer

HS- and H2S

 

NH3 and NH4

Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New