KA Chemical Process
Protecting an alcohol with tosyl chloride would likely have which of the following effects?
Decreasing its solubility in water.
In a system undergoing adiabatic compression, what are the values of internal energy and heat if work done on the system is 500 J?
Internal energy is 500 J and heat is 0 J adiabatic process = no heat transfer (q=0) int E = w + q
Kf
Keq/Ksp
Which of the following are true statements regarding enolate formation?
Low temperature reactions favor a more rapidly formed enolate
rate equation
R=k[A][B]
Keq
e^-deltaG/RT
NO3 and NO2 charges
-1
CrO4 charge
-2
SO4 and SO3 charges
-2
PO4 adn PO3 charges
-3
[H3O+]=10E4 pH?
-4 -log
HA Ka=10E-4 pH=6 [HA]=10E-8 [A-]?
10E-6M pH=pka+log[A-]/[HA] 6=4+log[A-]/[10E-8] 100x10E-8
What is the heat energy required to completely vaporize 10g of water beginning at 0 °C? (The heat capacity of water is 4.2 J/g⋅K and the ΔHvaporization of water is 2260 kJ/kg
26.8 kJ mcat = 10x4.2x100=4200 J + vaporization
Ka=1E-1 equilibrium conc [HA]=0.1M [A-]=10M pH?
3 pH=1+2 (HH eqn)
sulfur valence e-
6 so can have 6 bonds
Which of the following compounds will not create a precipitate upon addition into a saturated solution of potassium nitrate? KOH Ag2SO4 Hg2(NO3)2 NH4NO3
Ag2SO4 start w/ sat sol so more K and NO3=precipitate
Which of the following statements most accurately describes the comparison between the rate constant k and the equilibrium constant Keq?
Both constants are dependent on temperature, but only Keq is independent of concentration.
solubility rules
CASH-N-GIA Chlorates, Acetates, Sulfates, Halides (not Fluorides), Nitrates, Group I metals, Ammonium. HAPpy exceptions Hg2, Ag, and Pb2 Ca, Ba, Sr
acidic
CB is negative aldehyde more acidic than ketones
On which of the following physical properties does the separation of the constituents of a mixture by column chromatography depend?
Differential adsorption how well a solute adheres to the adsorbent in the column.
Which of the following statements accurately describes the difference between a sigma (σ) and a pi (π) bond?
Only sigma bonds use hybridized orbitals to overlap in forming the bond. sigma lower E than pi
Hemoglobin (HMB) molecules have 4 oxygen binding sites, that reversibly bind with O_2O2O, start subscript, 2, end subscript molecules. Loading HMB with an oxygen molecule creates a positive-feedback mechanism, making it easier to load subsequent molecules. In oxygen deprived tissues one molecule oxygen is released from HMB rich molecules favoring the release of the other molecules. What role is oxygen playing in these process?
Oxygen acts like an allosteric activator.
What is always true of spontaneous reactions?
They decrease free energy
nucleosides
adenosine, guanosine, cytidine, thymidine
enol reaction
alpha carbon acts as a nucleophile, and would accept the extra pair of electrons to form the carbanion more electronegative atom will be more stable with a negative charge
Which of the following is considered necessary as part of standard state conditions?
ambient pressure of 100,000 Pascals =1atm
what would inc Keq
dec T
molar solubility
direct measure of how much solid dissolves moles solute per liter of solution always greater than the solubility product constant
gas to liquid
exothermic
Given that nicotinamide adenine dinucleotide (NAD), in its reduced form as NADH, is a key electron-donating molecule in many metabolic reactions, which of the following is a good prediction for the standard reduction potential (E) of the reduction half-reaction of NAD?
less than positive standard reduction potential: measure of tendency of a chemical species to be reduced Electron accepting molecules like NAD have a strong tendency to be reduced under physiological conditions. The result is the electron-carrying molecule NADH
TLC
more polar solvent, greater eluting power (moves via capillary not gravity) stationary phase: solid polar (alumina, silica)
dissolution exothermic
more will not dissolve when the temperature increases.
cofactor
non-protein chemical compound bound to an enzyme to assist in catalysis.
Periodic acid (H5IO6) will selectively cleave vicinal diols into two aldehyde or ketone fragments, which can be used to label the 3'-termini of RNA instead of DNA. Periodic acid can be dehydrated twice to form metaperiodic acid. What are the molecular geometries of the two compounds respectively?
octahedral and tetrahedral
Enantiomers
same physical properties except for their ability to rotate plane-polarized light share the same chemical properties except when reacting with a chiral reagent.
Diastereomers
share similar chemical properties and have distinct physical properties that allow them to be separated by physical means.
SN2 rxn
strong nuc primary
fractional charge
total charge on the attaching atoms divided by the number of attaching ions
bond order
total number of bonds divided by the number of attaching atoms
formal charge
valence e- - nonbonding - bonding/2 more EN tend to have - formal charge
solids inc solubility
w/ inc T endothermic process Heat would be on the reactant side, and by adding more reactant, the equilibrium shifts to the right.
SN1 rxn
weak nuc (ethanol) lg, branched electrophiles w/ great leaving groups (tertiary)
oxyhalide anions, perchlorate (ClO4), chlorate (ClO3), chlorite (ClO2), and hypochlorite (ClO) charges
-1
Suppose a nanotechnological innovation allows every single charged ion to be precisely identified and removed from a small volume of water. Which of the following describes Ka for the water at the end of the process, assuming that the filtered water is given adequate time to re-equilibrate?
10E-14 in equilibrium
Which of the following carboxylic acids will yield the least amount of protons in an aqueous solution?
2-methylbutanoic acid least acidic molec A carboxylic acid with a longer carbon chain is less acidic due to the greater induction of electrons destabilizing the conjugate base anion.
Which of the following statements most accurately describes thin-layer chromatography?
A solvent with a greater eluting power than petroleum ether is acetic acid.
With regards to the Michaelis-Menten equation, a molecule that has the effect of increasing the Vmax of a reaction upon binding to an enzyme would be called what?
Activator inc vmax to speed rate of rxn
Which of the following is a correct statement explaining why toluene is an aromatic molecule?
All electron contributing atoms to the aromatic structure are on the same plane.
Which of the following will be true regarding enzymes saturated with substrate?
An enzyme with lower Km is more easily saturated than an enzyme with high Km
Suppose a large organic molecule X is classified as a Lewis acid, while another large molecule Y is classified as a Bronsted-Lowry acid. Which of the following most accurately describes a similarity in their behaviors in solution?
Both molecules will tend to acquire a net negative charge A Bronsted-Lowry acid tends to donate hydrogen ions, which have positive charges in solution. This leaves the rest of the molecule with a net negative charge. A Lewis acid tends to accept electrons in solution, leaving the molecule with a net negative charge
Which of the following best describes the respective free energy changes for the one-step combustion of glucose in the presence of oxygen as compared to the multi-step oxidation of glucose during cellular respiration, assuming both reactions occur under identical conditions?
Both reactions have the same change in free energy depends only on the initial and final state of a chemical system
CaF2 Ksp=4E-11 solubility of CaF2 in solution containing 0.10 M Ca(NO3)2 vs solution containing 0.10 M NaF
CaF2 is approximately 2500 times more soluble in a solution containing 0.10 M Ca(NO3)2 than in a solution containing 0.10 M NaF.
Chemical reactions can be classified according to free energy changes. A chemical reaction has a ΔG of -686/kcal/mol. Is this an endergonic or exergonic reaction? How would the addition of catalyst change the ΔG this reaction?
Exergonic, the catalyst would not reduce ΔG.
Which of the following statements most accurately describes the characteristics of diastereomers, enantiomers, and meso compounds?
For a given set of stereoisomers, meso compounds must have at least 2 stereocenters and are diastereomeric to the other stereoisomers in the set.
H bonding
HNOF gas molec don't H-bond; far apart
The major protein component of human hair is α-keratin. Hair 'straighteners' are commonly used tools which use heat to iron hair into temporarily lying flat and straight. What is the best biological explanation for this phenomenon?
Hair straighteners disrupt hydrogen bonds in α-keratin
S-Adenosyl methionine (SAM) is a molecule utilized in various metabolic pathways to transfer methyl groups from SAM to an acceptor. What is the proper designation of the complex of SAM and its enzyme together?
Holoenzyme describes the complex of an enzyme that has its cofactor bound and is considered 'complete'.
A hot object is placed next to a cold object so that they are touching. Which of the following statements is true?
I. Heat will transfer from the hot object to the cold object because the hot object has a higher temperature. internal energy does not necessarily get transferred from high internal energy to lower internal energy
Which of the following reactions are ways to synthesize carboxylic acids?
I. Oxidation of an aldehyde II. Hydrolysis of an anhydride
Which of the following is a true statement about the role of catalysts in a reaction?
II. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product. IV. Catalysts can may increase the reaction rate or selectivity or enable the reaction at a lower temperature.
Which of the following are true of reaction rates?
II. The presence of a catalyst will increase the number of molecules entering the transition state III. An increase in temperature will increase the rate of a reaction
Which of the following statements most accurately describes the difference between assigning formal charge and oxidation state?
In assigning oxidation states, we treat the bonds as if they are ionic bonds where the more electronegative atom is awarded the electrons.
Von Gierke disease is an autosomal recessive disorder characterized by a deficiency in the enzyme Glucose-6-phosphatase. Which of the following would most likely be observed in an individual with Von Gierke disease?
Increased glycogen in the liver Without this enzyme, gluconeogenesis cannot be completed.
Which of the following statements about the melting and boiling points of the organic compounds can be deduced most accurately represent the data below?
Most amides are solids at room temperature due to such high melting points, and for 1° and 2° amides, their high boiling points are attributed to the hydrogen bonding, and for 3° amides, to their high polarity.
Where within the cell is the majority of ATP produced from the complete metabolism of carbohydrates and lipids, respectively? Choose 1 answer:
Most of the ATP from the metabolism of carbohydrates is produced in the mitochondria, and most of the ATP from the metabolism of lipids is produced in the mitochondria
What is the balanced half-reaction for the reduction of nicotinamide adenine dinucleotide (NAD+)?
NAD+ + H+ +2e- to NADH
Nucleoside reverse transcriptase inhibitors (NRTIs) are used in the treatment of HIV. These drugs are synthetic nucleoside analogs, which compete with naturally occurring nucleosides for incorporation into a growing DNA chain. Unlike naturally occurring nucleosides, the phosphosugar of NRTIs lacks a 3' OH group. Knowing this, what effect would an NRTI have on DNA replication once incorporated into a growing DNA chain?
Prevent further chain elongation due to inability to form a phosphodiester bond Without a 3'OH, a phosphodiester bond cannot be formed, which terminates the chain's growth.
compounds, entropy r/s
Solids have less entropy than liquids which have less entropy than gases. greater molar mass or complexity have a greater entropy
One method for sterilizing the surface of an article contaminated with bacteria and bacteria spores is using an interhalogen compound such as ClF3 or CLF5. What is the molecular geometry of chlorine trifluoride?
T-shaped 3 attached
ATP hydrolysis is a spontaneous chemical reaction under standard physiological conditions: what is always true of spontaneous reactions?
That the products of the reaction have lower free energy than the reactants
Which of the following is true concerning the induced fit model of enzyme catalysis?
The active site can be influenced by molecules binding elsewhere on an enzyme
Which of the following describes the "buffer" region in a titration curve?
The flat portion of the curve just before the equivalence point
Atmospheric gases absorb more energy than they emit. If we consider a gas to be a closed system, which of the following is true?
The heat absorbed by the gas is positive.
Which of the following statements most accurately describes the details of the hybridization of sulfur hexafluoride?
The orbitals are all oriented such that all bond angles are 90° and have an octahedral configuration.
Titration curves exhibit an asymptote at very large volumes of added titrant. Which of the following experimental parameters determines the location of this asymptote?
The pH of the titrant
Consider the synthesis of methyl benzoate from benzoic acid and methanol, catalyzed by an acid chloride. How would this synthesis be affected if a carboxylic acid were used instead of the acid chloride?
The reaction can occur but will require an acid catalyst ; COOH less reactive than acid cl
Additional gas is pumped inside a rigid container that stores compressed gas. Which of the following is a true statement about this system?
There is no work done on the container. W=PdeltaV
keto-enol tautomerization reaction
acid/base catalysis rearranging of protons on a single molecule, like in a keto-enol tautomerization.
ion product
product of the concentrations of the ions at any moment in time. When the ion product is greater than the solubility product constant, the solution is considered unsaturated
solubility product constant
product of the concentrations of the ions present in solution concentration Ksp expression is raised to the power of the charge of the opposing ion.
Calculate delta H or S using data
products-reactants
Proximity or orientation catalysis
re-arranging of molecular bonds by the basic collision of two molecules together.
P charge
same group as N so 3 bonds is uncharged
covalent catalysis
sharing of electrons between two molecules.
overall rate law is determined by
slowest step
coenzyme
specific type of cofactor that carries chemical groups between enzymes, like methyl groups
Cis-platin [PtCl2(NH3)2] is an anti-cancer drug that reacts by binding to and causing the crosslinking of DNA ultimately leading to apoptosis and is the geometric isomer of trans-platin. Given that cis-platin exhibits stereochemistry, what would you predict is the molecular geometry of the anticancer drug?
square planar 4 attachments
