A hydrocarbon A has the molecular formula C8H14. Its NMR spectrum consists of a triplet at 1.2 ppm (relative peak area of 2), a triplet at 1.9 ppm (relative peak area of 2) and a singlet at 2.0 ppm (relative peak area of 3). When compound A is treated with Br2 in CCl4 (no light), a new compound B is formed with a molecular formula of C8H14Br2. The NMR spectrum of B looks the same as that of A, except that the positions of the triplets and the singlet are all shifted downfield. When compound B is treated with H2O, compound C is formed slowly (molecular formula C8H16O2). The NMR spectrum of C consists of a triplet at 2.1 ppm (relative peak area of 2), a triplet at 3.4 ppm (relative peak area of 2), a singlet at 3.5 ppm (relative area of 3) and a broad singlet at 4.9 ppm (relative area of 1). The singlet at 4.9 ppm disappears after the compound has been shaken with D2O. When compound B is treated with hot KOH, a new hydrocarbon D is formed as a major product, along with some minor geometric isomers. Compound D has a molecular formula of C8H12. The NMR spectrum of compound D consists of a doublet at 2.0 ppm (relative peak area of 2) which is coupled to a triplet at 4.2 ppm (relative peak area of 1) and a singlet at 2.1 ppm (relative peak area of 3).  

Write clear structural formulas for compounds A, B, C and D which are consistent with these observations and briefly explain your reasoning.

In essence, the__________ side chain is mimicking the__________ charge on BPG.

Describe the bonding between carbons in C2H4 using valence bond theory. Which of the following is true?

A closed system consists of 0.5kg of superheated steam initially at 1MPa, 300 ⁰C. The system undergoes a reversible isothermal process during which the steam condenses to a saturated liquid whilst exchanging heat wih a reservoir at 30⁰C. Show the process on a T-s diagram and calculate the change in enthropy (kJ/K) of the system, the reservoir (surroundings) and the universe.

C) For each strong base solution, determine [H3O+],[OH−], pH, and pOH.:

Express your answer using both three significant figures and then to three decimal places

8.84×10−3 M LiOH

1.12×10−2 M Ba(OH)

Express your answer using both two significant figures and two decimal places

2.2×10−4 M KOH

4.8×10−4 M Ca(OH)2

Justify the statement, “Tall stacks are no longer considered as an acceptable alternative for controlling emissions from electric power generating plants.”

I almost finished my pre-lab... but I am stuck! What are the energies of (-)-menthone and (+)-isomenthone? How can I find this (how to do it)?

Thank you for the help!

Determine the pH of a solution that is 1.65% NaOH by mass. Assume that the solution has density of 1.01 g/mL.

1.In your own words, explain the "surprise" in Planck's work and the social significance of the time (1900s).

2. Explain how fireworks work.

3. Explain the photoelectric effect and the dual nature of light.

4. Explain the evidence supporting that particles such as electrons have wavelengths.

5. Explain the relationship between the size of matter and its exhibition of particulate and the wave properties. Give examples not found on Wikipedia.

6. Why are 100ºF and 10% humidity more comfortable than 100ºF and 95% humidity?

The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4

What is the pH of the resulting solution after adding 100mL of 1.0M HCl to the original buffer solution?

A) 11.12 B) 10.64 C) 12.32 D) 0.48 E) 5.32 (Correct Answer: 5.32) Please show work, and explain why.

A student reacted 100.0 mL of 0.9800 M HCl with 100.0 mL of 0.9900 M NH3. The density of                          
the reaction mixture was 1.02 g/mL and the heat capacity was 4.016 J/g K.                          
Calculate the enthalpy of neutralization by plotting and using the data shown below.

Time(min) Temp(oC)
0.0 23.25
0.5 23.27
1.0 23.28
1.5 23.30
2.0 23.30
3.0 23.35
4.0 23.44
4.5 23.47
mix ---------
5.5 28.75
6.0 28.50
7.0 28.55
8.0 28.48
9.0 28.32
10.0 28.25
11.0 28.20
12.0 28.05
13.0 27.96
14.0 27.80
15.0 27.75

Using the data provided in the excel file, show all of your work for the following calculations:

a.) mean temperature of unmixed reagents (oC)

b.) δελταT from graph (oC)

c.) q absorbed by reaction mixture (J)

d.) q absorbed by calorimeter, stirrer, and thermometer (J)

e.) q total absorbed (J)

f.) q total released (J)

g.) calculation to show limiting reagent

h.) deltaH neutralization for the reaction (kJ/mole of acid)

A 67 g piece of aluminum at 725K is dropped into a 165 g of H2O (l) at 298K in an insulated container at 1 bar pressure. Calculate the temperature of the system once equilibrium has been reached. (Assume that Cp is independent on temperature)

Please explain the reactivity and orientation effects observed in each heterocycle. a. Pyridine is less reactive than benzene in electrophilic aromatic substitutions and yields 3-substituted products. b. Pyrrole is more reactive than benzene in electrophilic aromatic substitutions and yields 2-substituted products.

Consider the titration of 25.0 mL of 0.100 M acetic acid (HA) with 0.100 M NaOH.

1. Write the balanced chemical equation and equilibrium constant expression (ECE) for all of the reactions that occur when NaOH is added to the acetic throughout the titration. Hint: think of what is in the solution (acetic acid) with water, acetic acid with sodium hydroxide, and acetate ion with water) as the titration is proceeding.

2. Calculate the volume of NaOH solution needed to react the equivalence point.

3. The chart below has entries for several steps along the titration curve (which shows the pH as a function of the volume of NaOH solution added). To calculate the pH at each step, you must first understand what species are present and which chemical reactions are occurring, as that will dictate the method needed to calculate the pH.

For each volume listed, fill in the table with the major species (one or more) present in the solution that could impact the solution pH. Use stoichiometry! Based on what is present in solution, indicate whether Ka, Kb, the H-H (Henderson-Hasselbalch) equation, or the concentration of a strong acid or strong base in the solution will be used to calculate [H3O+] and the solution pH.

Complete the calculations.

4. Sketch the titration curve that would be obtained, graphing pH vs volume of NaOH needed. Label the equivalence point, the midpoint (halfway point) of the titration, and the buffer region.

Calculate the collision frequency for the N₂ – N₂ collisions, N₂ – O2 collisions and O₂ – O₂ collisions in air at 298 k and 0.95 bar pressure. Assume air is 80 % N2 and 20% O2 by mass and that σ = 0.43 nm² for both molecules.