Liquid (anhydrous) ammonia, NH3(l), with a boiling point of –33 °C, is often used as an alternate solvent to water. It forms strong hydrogen bonds and the polar molecules can solvate ionic compounds. Anhydrous ammonia also undergoes autoionization. Therefore, there can be acidic, neutral, or basic species in solutions of liquid ammonia.

a) Write the chemical equation, using the Brønsted‐Lowry perspective, that describes the autoionization of NH3(l). (Hints: for water this equation is 2H2O(l) ⇌ H3O+(aq) + OH–(aq); X(am) denotes a solute solvated by ammonia)

b) Identify the species in pure NH3(l) that can act as Brønsted acids and as Brønsted bases. (There are more than one for each case.)

c) Write the equilibrium expression for the autoionization constant Kam of liquid ammonia.

d) At 50°C, the autoionization constant of ammonia Kam is 1030. What are the conditions for “neutral”,

“acidic”, and “basic” liquid ammonia solutions at 50°C?

e) Propose a quantity, analog to the pH, that indicates the acidity of a liquid ammonia solution.

f) For each of these compounds: NH4Cl, LiNH2, KOH, N(CH3)3, when dissolved in liquid ammonia, identify whether it gives rise to an "acidic" solution or a "basic" solution. Write out the chemical equilibrium that shows how it behaves as an acid or a base in NH3(l).

Question 13:

Automobile airbags contain solid sodium azide, NaN3, that reacts to produce nitrogen gas when heated, thus inflating the bag.

2NaN3(s)--->2Na(s)+3N2(g)

Calculate the value of work, w, for the following system if 39.6g of NaN3 reacts completely at 1.00 atm and 22 C.

1. Calculate the number of moles produced

2.Calculate the volume of N2 using the number of moles, pressure, and temperature

3.Calculate the work using the change in volume and the pressure

How many grams of Mg(OH)2 will be needed to neutralize 25mL of stomach acid if stomach acid is .10M HCL?

How many mL of a .10 M NaOH solution are needed to neutralize 15mL of 0.20 M H3PO4 solution?

GC Analysis

a) is best done on solids dissolved in a volatile solvent

b) on neat high melting solids

c) on neat volatile liquids or solids

d) none of the above

I just want to see if my reasoning is correct and if not, why: it would be a) because the GC will recognize the solid in solution as a disruption in the gas more easily than b or c.

How would you drive a reaction that is endothermic and has a greater number of gaseous reactants than gaseous products?

You have to prepare a ph 3.50 buffer, and you have the following 0.10M solutions available: HCOOH, CH3COOH,H3PO4,HCOONa, CH3COONa, and NAH2PO4. Which solutions would you use? How many milliliters of each solution would you use to make approximately a liter of the buffer?

The answer on the textbook is 360mL of 0.10M HCOONa and 630mL of 0.10M HCOOH. I just need to know how did they get that answer.

Silver bromide, AgBr (s), is an essential reagent in black and white film developing. It is,

however, only sparingly soluble in water. AgBr (s) has K = 5.0 × 10-13, making it difficult to

rinse AgBr from the film negative with water.

Instead, excess AgBr is removed by an aqueous solution of sodium thiosulfate (Na2S2O3), which forms the complex ion Ag(S2O3)23-:

Ag+ (aq) + 2 S2O32- (aq) Ag(S2O3)23- (aq) Kf = 4.7 × 10+13 a) To see how this helps, first determine the molar solubility of AgBr (s) in water.

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b) The large formation constant of Ag(S2O3)23- (aq) means that almost all of the silver is complexed with the thiosulfate. To determine how much, calculate the [Ag+] at equilibrium in a 1.0 L solution that initially contains 0.001 M silver ions and 0.200 M sodium thiosulfate. Do so by setting up an ICE table and assuming that x is small compared to 0.200 (but not 0.001). Show that this results in a value of x = [Ag(S2O3)23-] = 0.001. In other words, all of the Ag+ complexes.

c) Your result from part b suggests that no Ag+ remains in solution. This obviously can’t be correct, since it would result in an infinitely large reaction quotient that wouldn’t be equal to an admittedly large equilibrium constant. To determine the correct [Ag+], use the equilibrium concentrations determined in part b as your initial concentrations in a new ICE table. Then use Kf to determine [Ag+]. [This approach is called a stoichiometric shift and is useful when a reaction starts with only reactants but goes almost to completion. Is essence, we are approaching the equilibrium from the direction of all Ag(S2O3)23- and no Ag+ as opposed to the direction of all Ag+ and no Ag(S2O3)23-.]

d) Before we determine the solubility of AgBr (s) in a thiosulfate solution, we need to know the appropriate equilibrium constant. To find it, determine the value of the equilibrium constant for the reaction:

AgBr (s) + 2 S2O32- (aq) <-->Ag(S2O3)23- (aq) + Br - (aq) Kc = ??

e) Finally, calculate the molar solubility of AgBr (s) in 1.0 M sodium thiosulfate. In other words, what is [Ag(S2O3)23-] for the reaction given in part d when the initial concentration of thiosulfate is 1.0 M?

At equilibrium, the concentrations in this system were found to be [N2]=[O2]=0.200 M and [NO]=0.500 M.

N2(g)+O2(g)<----->2NO(g)

If more NO is added, bringing its concentration to 0.800 M, what will the final concentration of NO be after equilibrium is re-established?

____________M

You want to know how many different products were produced by a new reaction you have devised. You spot the product mixture on a TLC plate and develop it in petroleum ether and observe a single spot at Rf 0.05.

a) Why does this experiment not confirm that only a single product was produced in the     reaction?                   

b) What change would you make to the mobile phase to gain more information about the composition of the product mixture?  

Use the density and molecular weight of limonene, linalool, and nonane to calculate the volumes of the compounds you will need to make the stock solution of 50 mM.

Also calculate the final concentration of those solutions after dilution.

Nonane: d = 0.718 g/mL, MW = 128.26, 99% pure

Limonene: d = 0.84 g/mL MW = 136.24, 96% pure

Linalool: d = 0.861 g/mL, MW = 154.25, 97% pure.

Molecule A has hydrogen bonds; Molecule B is non - polar. Which of the molecular liquids will have the higher boiling point? Why? Also, which of the molecular liquids will have the lower vapor pressure? Why?

You are the brewmaster at a local craft brewery. In an effort to cut costs, you have been tasked to develop a procedure to recover the carbon dioxide generated during the fermentation process. This recovered carbon dioxide will be used to later carbonate the beer before it is bottled. During fermentation, sucrose (C12H22O11) dissolved in water is broken down into ethanol (CH3CH2OH) and carbon dioxide by yeast. The carbon dioxide is then released into the space above the reaction where it is then captured using your novel device. To test your recovery method, you sprinkle 22 g of dry yeast into a rigid glass container that contains 10 gallons of water (1 gallon=3.78 liters). Then you add 4.5 kg of sucrose to simulate the wort (the sugary liquid that will be fermented into beer). The volume of the rigid glass container is 10.5 gallons and the fermentation temperature is controlled using a water bath set to 25°C.

a) Write a balanced equation for the fermentation process, including phases of each compound.

b) Calculate the volume of carbon dioxide that is released by the fermentation of 4.5 kg of sucrose. You can assume that the carbon dioxide is collected and kept at a constant pressure of 1 atm in a storage tank.

c) To properly carbonate your 10 gallon batch of beer, you need approximately 100 L of carbon dioxide at 1 atm. How many batches of beer can you carbonate with the amount of carbon dioxide generated by your experiment?

d) How much ethanol is produced during the fermentation of 4.5 kg sucrose. Express your answer in gallons.

e) Calculate the amount of heat generated by the fermentation of 4.5 kg sucrose. Express your answer in kJ.

1/ Calculate the volume of 0.280-M NaOH solution needed to completely neutralize 27.4 mL of a 0.560-M solution of the monoprotic acid HBr.

2/ To determine the molar mass of an organic acid, HA, we titrate 1.047 g of HA with standardized NaOH. Calculate the molar mass of HA assuming the acid reacts with 37.17 mL of 0.469 M NaOH according to the equation

HA(aq) + NaOH(aq) → NaA(aq) + H₂O(ℓ)

3/

2 NaBH₄(aq) + H₂SO₄(aq) → 2 H₂(g) + Na₂SO₄(aq) + B₂H₆(g)

What volume, in mL, of a 0.504 M solution of NaBH₄ is required to produce 0.539 g of B₂H₆? H₂SO₄ is present in excess.

please help me with all the questions i really need help to prepare for final!

Why is platinum the element of choice to study the trans effect?