CHEM 1C Lecture 6: Lecture 6

Hi could you help me with this problem please?

The following spectroscopic data were obtained for an organic compound:
i. MS (relative abundance in parentheses): M⁺ = 86 ; signals at 29 (92) and 41 (100) among others
ii. IR (cm^-1): 3100 (weak sharp), 2970 (medium sharp), 2850 (medium), 1650 (weak sharp), 1100 (strong sharp)
iii. H¹ NMR :
Signal A at 4 ppm (3H, triplet),
Signal B at 3.53 ppm (2H quartet),
Signal C at 4.01 ppm (2H, doublet),
Signal D₁ at 5.25 ppm (1H, doublet)
Signal D₂ at 5.28 ppm (1H, doublet)
Signal E at 5.95 ppm (1H, multiplet)
note: signal D₁ and D₂ are two separate signals, right next to each other, each with integration of 1H and multiplicity of "doublet"
iv. C13 NMR (proton \-decoupled):
Signal I at 14 ppm,
Signal II at 64 ppm,
Signal III at 71 ppm,
Signal IV at 115 ppm
Signal V at 135 ppm.

Please answer the following:
A. Draw the most likely structure of this compound. Show all of the hydrogens in the structure.

B. Label all H's with the signal letter that the Hproduces in the H¹ NMR spectrum. Explain why each H¹ NMR signal has the chemical shift specified. Be specific about each group of chemically-equivalent protons in this particular compound (not in general)

C. Explain multiplicities for EACH and EVERY H¹ NMR signal (i.e. what is each signal being split by?). Make sure to explain why there are actually two signals near 5.25 ppm (signals D₁ and D₂) that are both doublets, instead of a single signal that would be a doublet of doublets. Note: The hydrogens producing signals D₁ and D₂ are actually coupled to each other, but the coupling constant is so small that it is hard to see any coupling of D₁ with D₂ in the spectrum. The info for D₁ and D₂ above assume that J for these two protons is 0 Hz. Also assume that long-range coupling is not observed.

A block of copper of unknown mass has an initial temperature of69.6?C . The copper is immersed in a beaker containing 90.4g ofwater at 22.7?C . When the two substances reach thermalequilibrium, the final temperature is 24.4?C

What is the mass of the copper block?

Express your answer with the appropriateunits.

(a)

Calculate ?Hrxn for the following reaction:
CH4(g)+4Cl2(g)?CCl4(g)+4HCl(g)
Use the following reactions and given ?H?s.
C(s)+2H2(g)?CH4(g)?H=?74.6kJC(s)+2Cl2(g)?CCl4(g)?H=?95.7kJH2(g)+Cl2(g)?2HCl(g)?H=?184.6kJ

Express your answer using one decimalplace.

(b)

For each of the following, determine the value of ?H2in terms of ?H1.

A+B?2C,?H1
2C?A+B,?H2=?

Express your answer in terms of?H1.

A+1/2B?C,?H1
2C?2A+B,?H2=?

Express your answer in terms of?H1.

A?B+2C,?H1
1/2B+C?1/2A,?H2=?

Express your answer in terms of?H1.

(c)

Consider the following generic reaction: A+2B?C+3D, with?H = 171kJ . Determine the value of ?H for eachof the following related reactions.

3A+6B?3C+9D

C+3D?A+2B

12C+32D?2A+B

(d)

Consider the following reaction.
2 A + 3 B ? D ?H _rxn = 45.7 kJ
What is ?H _rxn for the followingreaction?
2 D ? 4 A + 6 B