Spectroscopy Worksheet printable pdf download

Spectroscopy Worksheet

CHEM 8L

Lab Calculations

**Work the problems below on a separate sheet of paper. Show your work

with units on every value using dimensional analysis.

1.The acid-promoted dehydration of alcohols affords a mixture of two alkene isomers, along with

water. Next week, students will carry out this reaction using with 750 µL of 1-

methylcyclohexanol (density = 0.919 g/mL) or 2-methylcyclohexanol (density = 0.93 g/mL) and

225 µL of a concentrated solution of phosphoric acid (85% w/w, sol’n density = 1.685 g/mL).

Note: “w/w” = weight per weight, which translates into 85 g of pure H

per 100 g of solution.

(cat.)

+ H

2-Methylcyclohexanol

1-Methylcyclohexene

3-Methylcyclohexene

(cat.)

+ H

1-Methylcyclohexanol

1-Methylcyclohexene

Methylenecyclohexane

(a) Convert the amounts of 1-methylcyclohexanol, 2-methylcyclohexanol, and phosphoric acid

into mmols. Calculate molar masses using the structures above.

(b)What is the limiting reagent in the reaction of 2-methylcyclohexanol with phosphoric acid?

What is the theoretical yield (in mg) of the mixture of alkenes in this reaction (both alkene

products have the same molecular mass)?

What is the theoretical yield in this reaction?

2.Unimolecular substitution (S

1) reactions are favored when tertiary substrates, such as 2-

methyl-2-butanol, are reacted with a good nucleophile (Cl

) under protic (acidic) conditions. The

reaction below will be completed during the lab practical. Students will combine 1.00 mL of 2-

methyl-2-butanol (density = 0.805 g/mL) with 2.5 mL of a concentrated solution of hydrochloric

acid (37% w/w, sol’n density = 1.2 g/mL).

HCl (conc.)

+ H

t-Pentanol

t-Pentyl chloride

(2-methyl-2-butanol)

(2-chloro-2-methyl-butane)

(a) Convert the amounts of 2-methyl-2-butanol and HCl into mmols. Calculate molar masses

using the structures above.

(b) What is the limiting reagent in this reaction? What is the theoretical yield (in mg) of the

chlorinated product (2-chloro-2-methylbutane)?

Spectroscopy Worksheet