Question

For each of the following, fill in the blank with the correct response. All of these fill-in-the-blank problems pertain to material covered in the sections on alkanes, alkenes and alkynes, aromatic hydrocarbons, and hydrocarbon derivatives. a. The first "organic" compound to be synthesized in the laboratory, rather than being isolated from nature, was ____ ,which was prepared from _______. b. An organic compound whose carbon-carbon bonds are all single bonds is said to be _________. c. The general orientation of the four pairs of electrons around the carbon atoms in alkanes is _______. d. Alkanes in which the carbon atoms form a single unbranched chain are said to be _______ alkanes. e. Structural isomerism occurs when two molecules have the same number of each type of atom but exhibit different arrangements of the _____ between those atoms. f. The systematic names of all saturated hydrocarbons have the ending _____ added to a root name that indicates the number of carbon atoms in the molecule. g.For a branched hydrocarbon, the root name for the hydrocarbon comes from the number of carbon atoms in the _______ continuous chain in the molecule. h.The positions of substituents along the hydrocarbon framework of a molecule are indicated by the _______ of the carbon atom to which the substituents are attached. i. The major use of alkanes has been in _______ reactions, as a source of heat and light. j. With very reactive agents, such as the halogen elements, alkanes undergo ________ reactions, whereby a new atom replaces one or more hydrogen atoms of the alkane. k. Alkenes and alkynes are characterized by their ability to undergo rapid, complete _______ reactions, by which other atoms attach themselves to the carbon atoms of the double or triple bond. l. Unsaturated fats may be converted to saturated fats by the process of __________. m. Benzene is the parent member of the group of hydrocarbons called ______ hydrocarbons. n.An atom or group of atoms that imparts new and characteristic properties to an organic molecule is called a ______ group. o.A _______ alcohol is one in which there is only one hydrocarbon group attached to the carbon atom holding the hydroxyl group. p.The simplest alcohol, methanol, is prepared industrially by the hydrogenation of ______. q. Ethanol is commonly prepared by ______ the of certain sugars by yeast. r. Both aldehydes and ketones contain ______ the but they differ in where this group occurs along the hvdrocarbon chain. s. Aldehydes and ketones can be prepared by of______ the corresponding alcohol. t. Organic acids, which contain the ________ group, are typically weak acids. u. The typically sweet-smelling compounds called ____ result from the condensation reaction of an organic acid with an ________.

Short answer

a. Urea, ammonium chloride and silver cyanate b. Saturated c. Tetrahedral d. Linear or straight-chain e. Bonds f. -ane g. Longest continuous chain h. Numbers i. Combustion j. Substitution k. Addition l. Hydrogenation m. Aromatic n. Functional group o. Primary p. Carbon monoxide q. Fermentation r. Carbonyl group s. Oxidation t. Carboxyl group u. Esters, alcohol

Step-by-step solution

Synthesized organic compound and its precursors

The first "organic" compound to be synthesized in the laboratory, rather than being isolated from nature, was urea, which was prepared from ammonium chloride and silver cyanate. b.

All single bonds

An organic compound whose carbon-carbon bonds are all single bonds is said to be saturated. c.

Orientation of electron pairs

The general orientation of the four pairs of electrons around the carbon atoms in alkanes is tetrahedral. d.

Unbranched alkanes

Alkanes in which the carbon atoms form a single unbranched chain are said to be linear or straight-chain alkanes. e.

Structural isomerism

Structural isomerism occurs when two molecules have the same number of each type of atom but exhibit different arrangements of the bonds between those atoms. f.

Systematic names of saturated hydrocarbons

The systematic names of all saturated hydrocarbons have the ending "-ane" added to a root name that indicates the number of carbon atoms in the molecule. g.

Root name for branched hydrocarbons

For a branched hydrocarbon, the root name for the hydrocarbon comes from the number of carbon atoms in the longest continuous chain in the molecule. h.

Positions of substituents

The positions of substituents along the hydrocarbon framework of a molecule are indicated by the numbers of the carbon atom to which the substituents are attached. i.

Major use of alkanes

The major use of alkanes has been in combustion reactions, as a source of heat and light. j.

Reactions with reactive agents

With very reactive agents, such as the halogen elements, alkanes undergo substitution reactions, whereby a new atom replaces one or more hydrogen atoms of the alkane. k.

Reactions of alkenes and alkynes

Alkenes and alkynes are characterized by their ability to undergo rapid, complete addition reactions, by which other atoms attach themselves to the carbon atoms of the double or triple bond. l.

Conversion of unsaturated to saturated fats

Unsaturated fats may be converted to saturated fats by the process of hydrogenation. m.

Parent member of aromatic hydrocarbons

Benzene is the parent member of the group of hydrocarbons called aromatic hydrocarbons. n.

Characteristic properties of organic molecules

An atom or group of atoms that imparts new and characteristic properties to an organic molecule is called a functional group. o.

Type of alcohol

A primary alcohol is one in which there is only one hydrocarbon group attached to the carbon atom holding the hydroxyl group. p.

Industrial preparation of methanol

The simplest alcohol, methanol, is prepared industrially by the hydrogenation of carbon monoxide. q.

Preparation of ethanol

Ethanol is commonly prepared by fermentation of certain sugars by yeast. r.

Similarity between aldehydes and ketones

Both aldehydes and ketones contain the carbonyl group, but they differ in where this group occurs along the hydrocarbon chain. s.

Preparation of aldehydes and ketones

Aldehydes and ketones can be prepared by oxidation of the corresponding alcohol. t.

Organic acids

Organic acids, which contain the carboxyl group, are typically weak acids. u.

Sweet-smelling compounds

The typically sweet-smelling compounds called esters result from the condensation reaction of an organic acid with an alcohol.

Key concepts

Hydrocarbons

Hydrocarbons are the simplest organic compounds, consisting solely of hydrogen and carbon atoms. These molecules form the backbone of organic chemistry and are categorized based on the types of bonds between their carbon atoms.
There are three main families of hydrocarbons:

• Alkanes: These are saturated hydrocarbons with only single bonds between carbon atoms. An example is methane, with the molecular formula CH₄.
• Alkenes: Unsaturated hydrocarbons containing at least one double bond, such as ethene (C₂H₄).
• Alkynes: These also belong to the unsaturated category and consist of at least one triple bond, like acetylene (C₂H₂).

Hydrocarbons can further be classified into aromatic and aliphatic compounds. Aromatics, like benzene, have ring structures with alternating double bonds. In contrast, aliphatic hydrocarbons are straight-chain or branched.

Functional Groups

Functional groups are specific groups of atoms within molecules that dictate the chemical reactions of those molecules. They are the essential feature in the study of organic chemistry because they determine the properties and reactivity of compounds.
Some common functional groups include:

• Hydroxyl group (-OH): Found in alcohols.
• Carbonyl group (C=O): Present in both aldehydes and ketones.
• Carboxyl group (-COOH): Characteristic of organic acids.
• Amine group (-NH₂): Found in amines.

These groups provide a way to predict the behavior of organic molecules. For example, the hydroxyl group in alcohols is polar, making these compounds soluble in water and capable of forming hydrogen bonds.

Saturated and Unsaturated Compounds

In organic chemistry, the terms saturated and unsaturated relate to the types of bonds between carbon atoms in a molecule:

• Saturated compounds have all carbon-carbon bonds as single bonds. These molecules are referred to as alkanes and are generally less reactive.
• Unsaturated compounds include those with double or triple carbon-carbon bonds, such as alkenes and alkynes, respectively. They are more reactive due to these bonds being more accessible to reactants.

The "saturation" concept is also vital in fats. Saturated fats have no double bonds and are solid at room temperature, while unsaturated fats contain one or more double bonds, making them liquid at room temperature.

Isomerism

Isomerism in organic chemistry occurs when two or more compounds share the same molecular formula but differ in how the atoms are arranged. This gives rise to different properties and activities, making isomerism a cornerstone subject in organic chemistry.
There are several types of isomerism:

• Structural isomerism: Compounds differ in the connectivity of their atoms. For instance, n-butane and isobutane have the same formula (C₄H₁₀) but distinct structures.
• Geometric isomerism: Occurs in compounds with double bonds or ring structures, resulting in different spatial arrangements, such as cis-trans isomers.
• Optical isomerism: Molecules that are mirror images of each other, like chiral molecules, which cannot be superimposed on one another.

Understanding isomers is crucial because their different structures can lead to vastly different chemical and physical properties, even though their formulas are identical.