Can all nuclei be studied by NMR? What property of a nucleus determines whether it is NMR active?
In: Chemistry
Name the acid used in baking powder and what role does it do in baking
In: Chemistry
Discuss the chemistry of the peroxo complexes of chromium(IV), (V), and (VI). (b) Discuss the electronic structure of Mn(III) compounds. (c) Discuss using suitable examples, the chemistry of manganese(IV) complexes.
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1.) Explain the advantages of a FT instrument over a constant wavelength diffuse instrument.
2.) Explain why Infrared spectroscopy uses interferometers rather than constant wavelength spectrometers.
In: Chemistry
1) For a first-order reaction, after 230s, 33% of the reactants remain. Calculate the rate constant for the reaction.
2) A compound decomposes with a half-life of 80s and the half-life is independent of the concentration. How long does it take for the concentration to decrease to one-ninth of its initial value?
In: Chemistry
1- does an alkyl substiuent in a ring favor the Friedel-Craft reaction?
2- what is the advatage of using tetramethylthiourea?
3 - what is the reagent(s) used for the thiolization of alkyl halides?
4- what is the use of the press in IR?
In: Chemistry
If 01.2 KOH is mixed with 0.05g of CO2 according to the following equation, 2KOH + CO2 -----> K2CO3+ H2O
a. What is the limiting reactant? ______________________
b. How many grams of K2CO3can be produced? ________________
c. What is the excess reactant? __________________
d. If 0.16g of K2CO3isolated, what is the % yield?
In: Chemistry
1. If the enzyme-catalyzed reaction E + S ↔ ES ↔ E + P takes place near Vmax to the enzyme (E), what can be concluded about the relative concentrations of S and ES?
a) High [S], [ES] is low
b) High [S], [ES] are at their maximum
c) Low [S], [ES] is low
d) Low [S], [ES] is at its maximum
2. Which of the following statements about Michaelis-Menten kinetics is correct?
a) Km = the substrate concentration required for the reaction to reach Vmax
b) Km = dissociation constant of the enzyme-substrate complex
c) Km = is a measure of the substrate's affinity for the enzyme
d) Km = expression of reaction rate
3. What is the Km value if the substrate concentration is 25 mM and the initial reaction rate is half Vmax for an enzyme catalyzed reaction?
a) Km = 50 mM
b) Km = 12.5 mM
c) Km = 625 mM
d) Km = 25 mM
In: Chemistry
Explain why we need/want a large magnetic field in NMR based on the following concepts:
a. kT and the Boltzmann distribution
b. the energy difference between the ground and excited states
c. the net magnetization of the sample
In: Chemistry
You decide to construct a zinc/aluminum galvanic cell in which the electrodes are connected by a wire and the solutions are connected with a salt bridge. One electrode consists of an aluminum bar in a 1.0 M solution of aluminum nitrate. The other electrode consists of zinc bar in a 1.0 M solution of zinc nitrate.
a. Which electrode is the cathode and which is the anode?
b. What is the direction of electron flow?
c. What chemical reactions are occurring at each electrode?
d. What is the overall balanced chemical reaction?
e. After a period of time, will the bar of zinc become heavier, lighter or stay the same? What about the aluminum bar?
f. What is the standard cell potential?
In: Chemistry
1. The stopcock connecting a 1.00 L bulb
containing krypton gas at a pressure of
414 mm Hg, and a 1.00 L bulb
containing oxygen gas at a pressure of
792 mm Hg, is opened and the gases are allowed to
mix. Assuming that the temperature remains constant, what is the
final pressure in the system?
mm Hg
2. A mixture of oxygen and
helium gases is maintained in a
5.33 L flask at a temperature of
13°C. If the partial pressure of
oxygen is 0.432 atm and the
partial pressure of helium is
0.314 atm, what is the total pressure in the
flask?
atm
In: Chemistry
For each of the following, specify if a reaction does or does not occur when the two reagents are combined, and justify your choice of reaction or no reaction. For each combination where a reaction does occur, write balanced molecular and net ionic equations for that reaction.
(NH4)2CO3(aq) + MgBr2(aq) →
Ni(C2H3O2)2(aq) + K3PO4(aq) →
Sr(OH)2(aq) + HC2H3O2(aq) →
CuSO4(aq) + Co(NO3)2(aq) →
Cs2CO3(aq) + HI(aq) →
Sr(OH)2(aq) + HBr(aq) →
H2SO4(aq) + KOH(aq) →
HCl(aq) + H2NCH2CH2NH2(aq) →
HO2CCO2H(aq) + NaOH(aq) →
In: Chemistry
You want to make a cheese sandwich with two slices of bread and one slice of cheese. For the following combinations state whether the limiting reagent is bread or cheese or neither.
A. 4 bread slices and 1 cheese slice.
B. 6 bread slices and 4 cheese slices.
C. 6 bread slices and 3 cheese slices.
D. 8 bread slices and 3 cheese slices.
E. 4 bread slices and 5 cheese slices.
F. 6 bread slices and 2 cheese slices.
G. 2 bread slices and 1 cheese slice.
H. 8 bread slices and 5 cheese slices.
In: Chemistry
. What kind of materials properties can be inferred from the shape of the interatomic bonding energy vs interatomic distance curves?
In: Chemistry
You need to prepare an acetate buffer of pH 6.50 from a 0.770 M acetic acid solution and a 2.85 M KOH solution. If you have 675 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a bufer of pH 6.50? The pKa of acetic acid is 4.76.
In: Chemistry