What are the changes in enthalpy, entropy, and free energy for the hydrogenation of C2H4 to C2H6, and C3H6 to C3H8 at 25 degrees C.

1. The molecular weight between crosslinks (MC) is one of the most important parameter that describes the thermoset network structure. Describe how the MC is related to the following properties:(a) T_g, (b) modulus, (c) elongation to break, and (d) solvent resistance. How do you measure MC value?

A zero order reaction starts with an initial concentration of reactant of 1.00 M and has a rate constant of 1.65x10^-5M/s. What is the concentration of the reactant after 100 seconds?

You have 525 mL of an 0.15 M acetic acid solution. What volume (V) of 2.00 M NaOH solution must you add in order to prepare an acetate buffer of pH = 5.32? (The pKa of acetic acid is 4.76.)

I'm trying to under stand the Haber process and this equilibrium reaction N2 +3H2 -----> 2NH3 + energy. In order to increase the yields of ammonia

1. remove amonia as it is formed

2. add an inhibitor

3. heat the reaction vessel

4. decrease the pressure in the reaction vessel.

5) Zn1+xO, Ti1+xO, Cu2S1+x, CuI1+x and ZnO1+x are semiconductors. What type of semiconductors are they (n- or p-type)?

One of the possible initial steps in the formation of acid rain is the oxidation of the pollutant SO2 to SO3 by the following reaction: SO2(g) + 1/2 O2(g) -> SO3(g) The reaction is exothermic, meaning that it is spontaneous at lower temperatures, but becomes nonspontaneous at higher temperatures. At what temperature does it change from being spontaneous to nonspontaneous?

Molecule ΔHf (kJ/mol) @ 25°C S (J/molK) @ 25°C

SO2(g) -296.8 248.2  

SO3(g) -395.7 256.8

503 K

1052 K

98.7 K

99.1 K

Consider the titration of 100.0 mL of 0.130 M H₂NNH₂ (K_b= 3.0 x 10^-6) by 0.260 M HNO₃. Calculate the pH of the resulting solution after the following volumes of  have been added: 0.0 mL, 20.0 mL, 40 mL, 50 mL, 100 mL.

What is the pH of a buffer solution made by dissolving 10 g of sodium acetate in 200 ml of 1M acetic acid? The Ka for acetic acid id 1.7*10^-5.

B. Calculate the pH of the solution if 10 ml of 0.100M HCl is added to the solution.

C. What will the pH be if 5.00 ml of 0.150M NaOH was added to solution in B?

D. Write the equation when an acid and a base are added to the buffer system.

Consider the system:

A (aq) → B (aq)

at 251 K where ΔG^oform A = -11.7 kJ/mol and ΔG^oform B = -14.1 kJ/mol. Calculate the concentration of A at equilibrium when 1.71 mol of A and 1.35 mol of B are mixed in water to form exactly one liter of solution.

Determine the concentrations of Na2CO3, Na , and CO32– in a solution prepared by dissolving 1.82 × 10–4 g Na2CO3 in 1.75 L of water. Express all three concentrations in molarity. Additionally, express the concentrations of the ionic species in parts per thousand (ppt). Note: Determine the formal concentration of CO32–. Ignore any reactions with water.

A solution of sodium hydroxide was neutralized by sulfuric acid. The volume of sodium hydroxide solution used was 675.0 mL, and the concentration was 0.875 M. Calculate the moles of sulfuric acid that were neutralized (assuming that the reaction goes to completion). Give your answer to three significant figures. 2NaOH (aq) + H2SO4 (aq) ? Na2SO4 (aq) + 2H2O (l

1.You find to your surprise that the reaction of phenol with acetic anhydride and aluminum trichloride gives a mixture of two disubstituted products. Pick the best reason for why.

A.The OH oxygen reacts twice to give the bisester derivative.

B.Ring acylation occurs twice in the ortho-ortho' and ortho-para positions.

C.The first acylation product is in the ortho and para positions which deactivates the ring and causes meta-substitution with the second acetyl group to give ortho-meta and meta-para diacetylphenols.

D.The first reaction is at the oxygen to give phenyl acetate followed by acetylation in the ortho and para positions to give a mixture of products.

2.Compare the reactivity of the oxygen to acetylation with acetic anhydride for phenol versus cyclohexanol by picking the best answer below.

A.Electron donation by the cyclohexane ring increases nucleophilic attack by the oxygen of cyclohexanol versus phenol.

B.Resonance is greater for the phenol acetyl oxonium intermediate than for the cyclohexanol analog.

C.Base catalyzed formation of the phenolate is faster than for cyclohexanol due to resonance stabilization, and the anion formed is more reactive.

D.In fact, they both react at the same rate.

3.EAS reactions involve attack by something seeking:

A.all of the below.

B.electrons, and those are almost always relatively "available" ones in pi-orbitals.

C.a nucleus to bond to, making the reaction also a "nucleophilic" attack.

D.a one-step reaction involving loss of leaving group at the same time the attacking group makes a new bond.

4.All EAS reactions involve a "tetrahedral" or Td intermediate. Which of the following is true of this statement?

A.Can't happen with an aromatic ring carbon which by definition is sp2 or trigonal planar.

B.There is no intermediate in EAS which simple involves attack at electrons.

C.No, the leaving group leaves at the same time the attacking group forms a bond.

D.Almost all do: an sp2 carbon becomes sp3 in the intermediate.

When NO2NO2 is bubbled into water, it is completely converted to HNO3HNO3 and HNO2HNO2:
2NO2(g)+H2O(l)→HNO3(aq)+HNO2(aq)

Part A

Calculate the pHpH in a solution prepared by dissolving 0.0360 molmol of NO2NO2 in 1.45 LL of water. KaKa for HNO2HNO2 is 4.5×10−44.5×10−4.

Express your answer using two decimal places.

Part B

Calculate the concentrations of all species present (H3O+H3O+, OH−OH−, HNO2HNO2, NO−2NO2− and NO−3NO3−) in a solution prepared by dissolving 0.0360 molmol of NO2NO2 in 1.45 LL of water.

Enter your answers numerically separated by commas.