有機化學導論與烷烴：练习题

In the context of laboratory safety, what is the most appropriate way to reduce the risk associated with a reaction involving a highly flammable liquid?

In the context of laboratory safety, which statement correctly distinguishes between a hazard and a risk?

In the petrochemical industry, the process of reforming is used to improve the quality of fuels. Which of the following equations represents a typical reforming reaction of heptane?

What is the IUPAC name of the branched alkane with the structural formula \( \text{CH}_3\text{CH(CH}_3\text{)CH(CH}_3\text{)CH}_3 \)?

Crude oil is separated into fractions by fractional distillation. Which statement correctly describes the properties of the fractions as they are collected from the top to the bottom of the fractionating column?

Write the balanced chemical equation, including state symbols, for the complete combustion of liquid octane, \(C_8H_{18}\), in excess oxygen gas.

The reaction between methane and chlorine is initiated by ultraviolet light. Describe the initiation step of the free radical substitution mechanism, stating the type of bond fission that occurs and the reactive species produced.

Define the process of reforming as used in the oil industry and explain how this process affects the combustion characteristics of alkane fuels in internal combustion engines.

Hexane and 2,2-dimethylbutane are structural isomers with the molecular formula \( \text{C}_6\text{H}_{14} \).

(a) Define the term structural isomerism. (1 point)
(b) Draw the skeletal formulae for both hexane and 2,2-dimethylbutane. (2 points)
(c) Explain why hexane has a higher boiling temperature than 2,2-dimethylbutane, referring to the intermolecular forces involved. (2 points)

The reaction between ethane, \(\text{C}_2\text{H}_6\), and bromine, \(\text{Br}_2\), in the presence of ultraviolet (UV) light proceeds through a free radical substitution mechanism.

(a) State the purpose of the UV light in this reaction and name the type of bond fission that occurs. (2 points)
(b) Write equations for the initiation step and the two propagation steps leading to the formation of bromoethane. (3 points)
(c) Write an equation for a termination step that produces a hydrocarbon with four carbon atoms. (1 point)
(d) Explain why this reaction is not a good method for preparing a pure sample of bromoethane. (2 points)