Reaction conditions and product isolation…

a)What is the purpose of using Silica Gel in this Fischer esterification reaction? Explain.

b) The crude reaction product did not still contain a large excess of acetic acid (this fact should be apparent from your GC results and your answer to Question 4. How was the excess acetic acid removed? Include a complete and balanced chemical reaction equation as the basis of your answer.

c)A large excess of acetic acid was used, what is the purpose of the excess?

d)Excess of 1-butanol could be also used, but practical considerations favor the method that you followed (excess of acetic acid rather than 1-butanol). Explain the complications that would arise during the product isolation step if you were to use an excess of 1-butanol instead.

Which 1H NMR peaks will be key for discriminating (E)-stilbene from mesostilbene dibromide?

A weak acid, (HA), has an acid dissociation constant of 4.60∙10–6. A 25.00 ml sample with a concentration of 0.1200 M is titrated with 0.1500 M NaOH. F. How many ml NaOH have been added at the equivalence point? g. What is the pH at the equivalence point?  

When 22.0 mL of a 5.10×10-4 M potassium hydroxide solution is combined with 12.0 mL of a 8.93×10-4 M magnesium nitrate solution does a precipitate form? (yes or no) For these conditions, the Reaction Quotient, Q, is equal to.

1.         When solid calcium carbonate reacts with hydrochloric acid, three products result.

a) Write the balanced equation to represent this reaction.

b) How many grams of calcium carbonate will fully react with 75.0 mL of HCl (density = 1.00 g/mL)?

c) When 25.2 grams of calcium carbonate is mixed with 65.0 mL HCl, which reactant is limiting?

d) Using the information obtained in c), how many grams of calcium chloride will be produced?

e) How many grams of the excess reactant will remain after the reaction goes to completion?

1.Calculate the OH^- in the saturated Ca(OH)₂ sol. from the results of this titration

2.Calculate the Ca²⁺

3. Calculate the Ksp for Ca(OH)₂

(3) A student accidentally uses toluene to triturate their crude product instead of methanol. Moments after heating, their crude product dissolves completely.

1. Explain why the result was undesirable, drawing comparisons between recrystallization and trituration.
2. Propose a solution to recover the student’s product involving a technique utilized in this lab.
3. Explain the difficulty using the technique proposed in (b) with the solvent that the student has dissolved their product in.

d. Propose a solution to the problem above.

In muscle tissue, the ratio of phosphorylase a to phosphorylase b determines the rate of conversion of glycogen to glucose 1‑phosphate.

Classify how each event affects the rate of glycogen breakdown in isolated muscle tissue.

Increased rate

Decreased rate

No change

Answer Bank

AMP allosteric binding activates phosphorylase b

removal of phosphate groups from phosphorylase a

addition of phosphorylase b kinase

[ATP] exceeds [AMP]

addition of a kinase inhibitor

treatment with insulin

addition of a phosphatase inhibitor

treatment with glucagon

During mid-January 2004, average gas concentrations measured in Cache Valley were:

ammonium (NH4) = 16 µg/m^3

nitrate (NO3) = 45 µg/m^3

NH4 + NO3 = NH4NO3 (s)

a) Is NH4 or NO3 the limiting factor for the formation of NH4NO3? Explain using appropriate calculations.

b) Calculate the average NH4NO3 concentration (µg/m^3) based on these concentrations.

c) If we could reduce ammonium emissions by 15% by changing the composition of cattle feed, but nitrate remained the same, calculate the average NH4NO3 concentration (µg/m^3).

d) If we could reduce nitrate emissions by 15% through a vehicle inspection program, but ammonia remained the same, calculate the average NH4NO3 concentration (µg/m^3).

e) Based on your answers to part c) and d), which pollutant (NH4 or NO3) should we target first?

PS. This is an environmental engineering.

A 27.5 L sample of oxygen gas is at 25°C and 1.05 atm. If the gas is cooled to –

40.°C while the pressure is increased to 2.00 atm, calculate the new volume of the

gas.

Can u please show with dymentional analysis?

Suppose that you have 175mL of a buffer that is .150M in both formic acid and its conjugate base.

a) what is the buffer range of the buffer solution?

b) what is the buffer capacity?

An electrolysis cell is operated for 3000 s using a current of 1.50 A. From which 1.0 M solution will the greatest mass of metal be deposited? Answer is A please explain

(A) TlNO3

(C) ZnCl2

(B) Pb(NO3)2

(D) In(NO3)3

Which of the following reactions in the stratosphere cause an increase in temperature there?

Check all that apply.

Check all that apply.

1)To determine the oxidation state of a monoatomic ion, first determine the charge of the ion. The oxidation state will be the same as the charge. For example, I forms the monoatomic ion I−; therefore, the oxidation state of the monoatomic ion for I is −1.

What is the oxidation number of the monoatomic ions of the following elements?

Drag each item to the appropriate bin.

Ca, Cs, F, Rb, Mg, Po, S, B, K, N, I

[Bins] +3, +2, +1, -1, -2, -3

2)For the following reaction, calculate ΔH∘rxn, ΔS∘rxn, and ΔG∘rxn at 25 ∘C.

NH4Cl(s)→HCl(g)+NH3(g)

3) For each reaction, identify the substance being oxidized and the substance being reduced.

Ni2+(aq)+Mg(s)→Mg2+(aq)+Ni(s)

4)In acidic solution, the nitrate ion can be used to react with a number of metal ions. One such reaction is

NO3−(aq)+Sn2+(aq)→NO2(aq)+Sn4+(aq)

Since this reaction takes place in acidic solution, H2O(l) and H+(aq) will be involved in the reaction. Places for these species are indicated by the blanks in the following restatement of the equation:

NO3−(aq)+Sn2+(aq)+     −−−→NO2(aq)+Sn4+(aq)+

What are the coefficients of the reactants and products in the balanced equation above? Remember to include H2O(l) and H+(aq) in the appropriate blanks. Your answer should have six terms.

Enter the equation coefficients in order separated by commas (e.g., 2,2,1,4,4,3). Include coefficients of 1, as required, for grading purposes.

5) Classify each half-reaction occurring in acidic aqueous solution as an oxidation or a reduction and balance the half-reaction.

S(s)→H2S(g)

S2O8^2−(aq)→2SO4^2−(aq)

Cr2O7^2−(aq)→Cr3+(aq)

NO(g)→NO3−(aq)

6) Balance each redox reaction occurring in basic aqueous solution.

Express your answer as a chemical equation. Identify all of the phases in your answer.

H2O2(aq)+ClO2(aq)→ClO−2(aq)+O2(g)

Al(s)+MnO−4(aq)→MnO2(s)+Al(OH)−4(aq)

Cl2(g)→Cl−(aq)+ClO−(aq)

7) Classify each reaction as spontaneous or nonspontaneous.

Cr(s) + 3Ag^+(aq)>Cr^3+(aq)+3Ag(s)

Cu(s)+Ca^2+(aq)>Cu^2+(aq) + Ca(s)

Ca(s)+Ni^2+(aq)>Ca^2+(aq)+Ni(s)

Mg(s)+2K^+(aq)>Mg^2+(aq)+2K(s)

Cu(s)2Ag^+(aq)>Cu^2+(aq)+2Ag(2)

Sn(s)+Ni^2+(aq)>Sn^2+(aq)+Ni(s)

For a 0.0299 M aqueous solution of aniline, C₆H₅NH₂ (K_b = 7.4E-10), determine the following. K_w = 1.0E-14.

What are the major and minor species present? Include phase.

What is the major species (other than water)?

What is the minor species (other than H3O+ and OH-)?

What is the concentration of the minor species in the solution? (M)

What is the concentration of the major species in the solution? (M)

What is the concentration of H₃O⁺ in the solution? (M)

What is the concentration of OH^- in the solution? (M)

Find the pH.