What distinguishes the mass spectrum of 2,2-dimethylpropane from the mass spectra of pentane and isopentane?

What is the most likely m/z value for the base peak in the mass spectrum of 3-methylpentane?

Determine the molecular formula for each of the following:

b. a compound that contains C, H, and one O and has a molecular ion with an m/z value of 100

Suggest possible molecular formulas for a compound that has a molecular ion with an m/z value of 86.

Can one of the possible molecular formulas contain a nitrogen atom?

Identify the hydrocarbon that has a molecular ion with an m/z value of 128, a base peak with an m/z value of 43, and significant peaks with m/z values of 57, 71, and 85.

Predict the relative intensities of the molecular ion peak, the M+2 peak, and the M+4 peak for a compound that contains two bromine atoms.

Can a high-resolution mass spectrometer distinguish between them?

The mass spectra of 1-methoxybutane, 2-methoxybutane, and 2-methoxy-2-methylpropane are shown below. Match each compound with its spectrum.

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Primary alcohols have a strong peak at m/z = 31.

a. What fragment is responsible for this peak?

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

b.

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

c.

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

d.

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

f.

The reaction of (Z)-2-pentene with water and a trace of H₂SO₄ forms two products. Identify the products from their mass spectra.

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a. Which occurs at a larger wavenumber:

3. a C–N stretch or a C=N stretch?

4. a C=O stretch or a C–O stretch?

a. Which occurs at a larger wavenumber:

1. a C=C stretch or a C=C stretch?

2. a C–H stretch or a C–H bend?

Which occurs at a larger wavenumber:

a. the C–O stretch of phenol or the C–O stretch of cyclohexanol?

b. the C=O stretch of a ketone or the C=O stretch of an amide?

c. the C–N stretch of cyclohexylamine or the C–N stretch of aniline?

Why is the C–O absorption band of 1-hexanol at a smaller wavenumber (1060 cm^–1) than the C–O absorption band of pentanoic acid (1220 cm^–1)?

Rank the following compounds from highest wavenumber to lowest wavenumber for their C=O absorption bands:

b.

Which shows an O–H stretch at a larger wavenumber: ethanol dissolved in carbon disulfide or an undiluted sample of ethanol?

A nitrogen-containing compound shows no absorption band at ~3400 cm^-1 and no absorption bands between ~1700 cm^-1 and ~1600 cm^-1 or between 2260 cm^-1 and 2220 cm^-1. What class of compound is it?

How can IR spectroscopy be used to distinguish between the following compounds?

a. a ketone and an aldehyde

b. a cyclic ketone and an open-chain ketone

How can IR spectroscopy be used to distinguish between the following compounds?

e. cyclohexene and cyclohexane

f. a primary amine and a tertiary amine

For each of the following pairs of compounds, name one absorption band that can be used to distinguish between them.

c.

d.

For each of the following pairs of compounds, name one absorption band that can be used to distinguish between them.

e.

f.

Which of the following compounds has a vibration that is infrared inactive?

1-butyne, 2-butyne, H₂, H₂O, Cl₂, ethene

Identify the compound that gives the mass spectrum and infrared spectrum shown here.

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A 4.0 × 10^-5 M solution of a compound in hexane shows an absorbance of 0.40 at 252 nm in a cell with a 1 cm light path. What is the molar absorptivity of the compound in hexane at 252 nm?

Predict the λ_max of the following compound: