Question 1

Which of the following statements best distinguishes organic compounds from inorganic compounds?

Accepted Answer

Organic compounds always contain carbon and hydrogen, while inorganic compounds may not contain carbon.

Question 2

What is the general formula for a straight-chain alkane, and how many hydrogen atoms are present in an alkane with 8 carbon atoms?

Accepted Answer

General formula: $$C_nH_{2n+2}$$; For $$n=8$$, $$C_8H_{18}$$

Question 3

Which of the following best explains why hydrocarbons are generally insoluble in water?

Accepted Answer

Hydrocarbons are nonpolar molecules, and water is polar, so they do not mix.

Question 4

A hydrocarbon is found to have the condensed formula $$CH_3CH_2CH_2CH_3. $$What is its molecular formula and IUPAC name?

Accepted Answer

Molecular formula: $$C_4H_{10}$$; Name: butane

Question 5

Which of the following properties is most typical of an organic compound?

Accepted Answer

Low melting point and high flammability

Question 6

Rank the following alkanes in order of increasing boiling point: methane ($$CH_4$$), ethane ($$C_2H_6$$), butane ($$C_4H_{10}$$), hexane ($$C_6H_{14}).$$

Accepted Answer

$$CH_4$$ \u003c C_2H_6 \u003c C_4H_{10} \u003c C_6H_{14}$$

Question 7

Which of the following is a correct line-angle formula representation for pentane?

Accepted Answer

A zig-zag line with four bends (five carbon atoms)

Question 8

A student is given a hydrocarbon with the formula $$C_7H_{16}. $$What is the name of this compound according to IUPAC nomenclature?

Accepted Answer

Heptane

Question 9

Which of the following best describes the bonding in alkanes?

Accepted Answer

Only single covalent bonds between carbon and hydrogen or carbon and carbon

Question 10

Which of the following is an example of an aromatic hydrocarbon?

Accepted Answer

Benzene

Question 11

A laboratory technician needs a nonpolar solvent to dissolve a sample. Which of the following would be the best choice?

Accepted Answer

Hexane ($$C_6H_{14})$$

Question 12

Which of the following statements about the physical properties of alkanes is correct?

Accepted Answer

As the number of carbon atoms increases, the boiling point increases.

Question 13

Which of the following best describes the difference between aliphatic and aromatic hydrocarbons?

Accepted Answer

Aliphatic hydrocarbons do not contain benzene rings, while aromatic hydrocarbons do.

Question 14

A sample of propane is used as a fuel. Which of the following is its molecular formula?

Accepted Answer

$$C_3H_8$$

Question 15

Which of the following is a correct condensed formula for hexane?

Accepted Answer

$$CH_3$$($$CH_2)_4CH_3$

Question 16

Which of the following is NOT a property of most organic compounds?

Accepted Answer

High melting point

Question 17

A hydrocarbon is found to be nonpolar, insoluble in water, and highly flammable. Which class of compounds does it most likely belong to?

Accepted Answer

Alkanes

Question 18

Which of the following best explains why sodium chloride ($$NaCl) is $$classified as an inorganic compound?

Accepted Answer

It is composed of a metal and a nonmetal and forms ionic bonds.

Question 19

Which of the following is the correct IUPAC name for the compound with the condensed formula $$CH_3CH_2CH_2CH_2CH_2CH_3$$?

Accepted Answer

Hexane

Question 20

A student is asked to draw the expanded structural formula for butane. Which of the following is correct?

Accepted Answer

$$\begin{array}{cccc} H & H & H & H \ | & | & | & | \ H-C-C-C-C-H \ | & | & | & | \ H & H & H & H \end{array}$$

Introduction to Organic Chemistry: Hydrocarbons (Ch. 11) Study Guide

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