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

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?

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

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) →

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.

. What kind of materials properties can be inferred from the shape of the interatomic bonding energy vs interatomic distance curves?

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.

Given that the specific heat capacities of ice and steam are 2.06 J/g°C and 2.03 J/g°C, the molar heats of fusion and vaporization for water are 6.02 kJ/mol and 40.6 kJ/mol, respectively, and the specific heat capacity of water is 4.18 J/g°C, calculate the total quantity of heat evolved when 27.1 g of steam at 216°C is condensed, cooled, and frozen to ice at -50.°C.

______KJ

Please show the steps

20.0 mL of nitric acid (HNO3) solution is neutralized with 30.0 mL 0.10M of potassium hydroxide (KOH) solution. what is the concentration of nitric acid solution? The answer is 0.67 M but how do you get that?

1mol of an ideal gas is inside a cylinder with a piston under a pressure of 6 atm. When reducing the pressure to 2 atm at constant T = 300K:
(a) Who is doing work, the piston or the gas?
(b) What is the type of process for the maximum work? Find the maximum amount of work.
(c) What is the type of process for the minimum work? Find the minimum amount of work.

Calculate the change of enthalpy for: 4S + 6O2= 4SO3 Delta H= ___ kJ

In all ligand titrations, the concentration of ligand is varied around the KD of the complex. In a stoichiometric titration, what is the concentration of receptor in relationship to KD? How does this differ from a binding titration experiment? Can you get a KD from a stoichiometric binding Titration? Why do the stoichiometric titration experiment this way, and what kind of information does it give you?

What is the theoretical (minimum) number of equivalents of methylmagnesium iodide (CHMgI) needed for reaction with benzoin? How many equivalents of CH3MgI did you use relative to benzoin and why is this number of equivalents necessary for the reaction?

In this experiment, we used 0.287g of magnesium turnings with 13mL of a 1.0M solution of methyl iodide (CH3I) in anhydrous diethyl ether to synthesize methylmagnesium iodide (CHMgI)

We then reacted methylmagnesium iodide (CHMgI) with 0.507g of a benzoin solution in 10mL of anhydrous CH2Cl2

3. Natural gas is a mixture of hydrocarbons and recent developments in directional drilling and hydraulic stimulation has seen that the majority of natural gas is now produced from shale gases. These gases may contain higher proportions of higher alkanes. In order for these gases to be used via the pipeline, they must meet certain pipeline quality standards. These standards are even stricter when the natural gas is to be used by natural gas vehicles. Suppose natural gas from a shale well enters your furnace. The pressure and temperature of the mixture are 17 °C and 100 kPa. A molar analysis shows the gas is 80% methane, 10% ethane, and 10% propane. Determine the following:

a.) Mass fraction of each component (10 points)

b.) The partial pressure of each component (10 points)

c.) The mass flow rate in kg/s for a volumetric flowrate of 1m3 /sec (10 points)

For each of the following octahedral complexes:

a) determine the number of 'd' electrons on the metal atom.

b) determine the number of unpaired electrons on the metal atom.

c) calculate the magnetic moment (spin only value) in units of Bohr magnetons.

d) calculate the ligand field stabilization energy, LFSE, in units of delta0

1)[Mn(H2O)6]2+

2)[CrCl6]4-

3)[NiF6]3-

4)[Co(CN)6]4-

5)[Mn(CO)6]+