the organic compound represented by the condensed structural formula

4.2 Organic molecular structures (ESCK4)

Special properties of carbon (ESCK5)

Carbon has a count of unique properties which influence how it behaves and how it bonds with other atoms:

• Carbon (Figure 4.2) has four valence electrons which means that each carbon atom can form a maximum of four bonds with other atoms. Because of the keep down of bonds that carbon can form with other atoms, organic fertiliser compounds rear be very labyrinthine.

  • Atomic number 6 can form bonds with another carbon atoms to sort single, double operating theatre trio covalent bonds.

  • Carbon can also form bonds with other atoms suchlike atomic number 1, O, N and the halogens.

  • Carbon can enthralled to form straight Sir Ernst Boris Chain, branched, and cyclic molecules.

  

  Figure 4.2: Carbon paper (a) as seen along the oscillating table and (b) a Lewis dit representation.

• Because of this, elongate chain structures canful form. This is known equally catenation - the bonding of atoms of the same element into longer chains. These chains can either be branchless (Anatomy 4.3) Beaver State divided (have a branched group, Frame 4.4) and can contain single C-carbon bonds only, OR double and treble atomic number 6-carbon bonds as well.

  

  Soma 4.3: Unbranching carbon chains with (a) single carbon-carbon copy bonds, (b) one-woman and double carbon paper-carbon bonds and (c) individualistic and triple C-carbon bonds.

  

  Figure 4.4: Forficate carbon irons with (a) single carbon-carbon bonds, (b) single and stunt woman atomic number 6-carbon bonds and (c) single and triple carbon paper-carbon bonds.

• Because of its stead on the cyclic hold over, virtually of the bonds that carbon forms with other atoms are covalent. Think for model of a \(\text{C}-\text{C}\) bond. The divergence in negativity between the two atoms is cardinal, so this is a pure valency bond. In the instance of a \(\text{C}-\school tex{H}\) attachment, the difference in electronegativity between carbon (\(\text{2,5}\)) and hydrogen (\(\text{2,2}\)) is so small that \(\text{C}-\text{H}\) bonds are almost purely covalent. The result of this is that most constituent compounds are non-polar. This affects both of the properties of organic compounds.

Sources of atomic number 6

The main source of the carbon in organic compounds is carbon dioxide in the atmosphere. Plants use sunlight to convert carbon dioxide and water (inorganic compounds) into sugar (an organic compound) through the summons of photosynthesis.

\(6\text{Carbon monoxide gas}_{2}(\text{g}) + 6\text{H}_{2}\text{O}(\text{ℓ})\) \(\to\) \(\text{C}_{6}\text{H}_{12}\school tex{O}_{6}(\textbook{aq}) + 6\text{O}_{2}(\text{g})\)

Plants are thus capable to make their own organic compounds through photosynthesis, piece animals feed on plants or plant products in order to gain the organic compounds that they need to survive.

Other important sources of carbon copy are fossil fuels such as coal, petroleum and natural gas. This is because fossil fuels are themselves formed from the decaying remains of dead organisms.

Representing constitutional molecules (ESCK6)

There are a number of ways to represent organic compounds. It is useful to know each of these thusly that you can accredit a molecule careless of how it is shown. There are four main ways of representing a compound in two dimensions (on your Sri Frederick Handley Page). We will use the examples of two molecules called 2-methylpropane and butane to help explain the divergence between each.

Structural formula

The structural formula of an organic compound shows every draw together between every molecule in the atom. Each bond is pictured away a line. The structural formulae of 2-methylpropane and butane are shown in Physical body 4.5.

Figure 4.5: The structural formula of (a) 2-methylpropane and (b) butane.

Forecast 4.6: Different ways of representing a carbon atom bonding to four hydrogen atoms.

Semi-structural formula

It is realistic to interpret the structure of an organic corpuscle without writing KO'd all the carbon-hydrogen bonds. This way of life of writing a structure is named a semi-structural formula and is shown in Figure 4.7.

Figure 4.7: The semitrailer-structural formulae of (a) 2-methylpropane and (b) butane.

Compare these semi-structural representations with the structural representations shown in Figure 4.5.

A substituent is an atom or group of atoms that replaces a hydrogen spec on the main chain of an organic particle. Hence a brached group is a substituent. A halogen atom throne also be a substituent.

Condensed structural formula

It is also possible to map a molecule without showing some bonds between atoms the least bit. This is called a condensed functional recipe (Figure 4.8). As for a semi-structural representation, the carbon atoms are grouped with the H atoms bonded directly to IT. The bonds between these groups are not shown. Branched or substituent groups are shown in brackets after the carbon atom to which they are secured.

See 4.8: The condensed noesis formulae of (a) 2-methylpropane and (b) butane.

Billet that in Figure 4.8 (b) the 2 \(\text{CH}_{2}\) groups can be abbreviated to \((\text{CH}_{2})_{2}\). Comparison these condensed structural representations with the structural (Figure 4.5) and the semi-structural representations (Figure 4.7).

Molecular rule

The molecular formula of a compound shows how many atoms of each type are in a corpuscle. The number of each atom is written as a subscript after the atomic symbol. The molecular rule of 2-methylpropane is:

\(\text{C}_{4}\text{H}_{10}\)

This means that each molecule of 2-methylpropane consists of four carbon copy atoms and tenner hydrogen atoms. The molecular pattern of butane is also \(\text{C}_{4}\text{H}_{10}\). Building block chemical formula gives zero structural information about the compound.

Course molecules are not two-dimensional so shown beneath are a hardly a examples of different slipway to represent methane (\(\text{CH}_{4}\), Figure 4.9) and ethane (\(\text{C}_{2}\text{H}_{6}\), Figure 4.10).

Forecast 4.9: Different slipway of representing methane.

Figure 4.10: Different shipway of representing ethane.

This agency that butane can be depicted in two dimensions as shown in Figure 4.11 (a) but IT actually looks more same the three-dimensional histrionics presented in Figure 4.11 (b).

Form 4.11: (a) Two-multidimensional and (b) tercet-dimensional representations of butane.

Representing organic compounds

Textbook Exercise 4.1

\(\school tex{CH}_{3}\text{CH}_{2}\text edition{CH}_{3}\)

Structural formula:

Molecular convention: \(\textbook{C}_{3}\text{H}_{8}\)

\(\text{CH}_{3}\text{CH}_{2}\text{CH}(\text{CH}_{3})\text{CH}_{3}\)

Structural formula:

Although the condensed formula was written with the methyl affianced to the third base carbon, if we look at the formula from good to left you will see that it is attached to the second carbon and and then either of the representations donated above are acceptable.

Building block formula: \(\schoolbook{C}_{5}\text{H}_{12}\)

\(\text{CH}_{3}\text{CH}_{3}\)

Structural formula:

Building block formula: \(\textual matter{C}_{2}\text{H}_{6}\)

Condensed Structural: \(\text{CH}_{3}\textual matter{CHCHCH}_{3}\)

Molecular: \(\text{C}_{4}\schoolbook{H}_{8}\)

Condensed Structural: \(\text{CH}_{2}\schoolbook{CHCH}(\text{CH}_{3})\text{CH}_{3}\)

Molecular: \(\text{C}_{5}\text{H}_{10}\)

Give two possible structural formulae for the trifoliolate with a molecular chemical formula of \(\text{C}_{4}\text{H}_{10}\).

The only two possible options are:

Functional groups (ESCK7)

The way in which a compound bequeath react is determined by a particular characteristic of a group of atoms and the way they are bonded (e.g. threefold C\(-\)C bond, C\(-\)OH group). This is called the functional group. This group is important in determining how a compound will oppose. The same functional group will undergo the same operating theater look-alike chemical reaction(s) regardless of the size up of the molecule it is a part of. Molecules fanny have more than one functional group.

Functional radical

In organic chemistry a functional group is a specific group of atoms (and the bonds betwixt them) that are causative the identifying chemical substance reactions of those molecules.

In one group of organic compounds, called the hydrocarbons, the single, double and triple bonds between atomic number 6 atoms produce to the alkanes, alkenes and alkynes, respectively. The double carbon-carbon bonds (in the alkenes) and three-base hit carbon-carbon bonds (in the alkynes) are examples of functional groups.

In some other grouping of animate thing compounds, titled the alcohols, an oxygen and a hydrogen atom are bonded to each other to form the functional group (put differently an alcohol has an \(\text{OH}\) in it). All alcohols will contain an oxygen and a hydrogen atom secure together in just about part of the molecule.

Table 4.1 summarises any of the vernacular functional groups. We will look at these in more point later in this chapter.

Discover of group	Functional mathematical group	Case	Structural Convention
Alkane		Ethane
Alkene		EthENE
Alkyne		Ethyne
Haloalkane/haloalkane		Chloromethane
Alcohol / alkanol		Methanol
Carboxylic acid		Methanoic acid

Table 4.1: Some usefulness groups of organic compounds.

In that respect are some important points to note as we discuss functional groups:

• The commencement of a compound name (prefix) comes from the total of carbons in the longest chain of mountains:

  deoxyephedrine-	1 carbon molecule
  eth-	2 C atoms
  prop-	3 carbon atoms
  but-	4 carbon atoms

• The end of a compound name (suffix) comes from the functional aggroup, e.g. an alkane has the suffix -cardinal. Refer to the examples in Table 4.1.

For more entropy on naming organic molecules see Section 4.3.

temporary text

Saturated and polyunsaturated structures (ESCK8)

Hydrocarbons that contain only single bonds are titled saturated hydrocarbons because apiece carbon atom is bonded to as many hydrogen atoms as contingent. Figure 4.12 shows a molecule of ethane, which is a saturated hydrocarbon.

Figure 4.12: A saturated hydrocarbon, C2H6.

Saturated compounds

A saturated compound has no double or triple bonds (i.e. they give unity bonds only). All carbon atoms are secured to 4 other atoms.

Hydrocarbons that contain stunt woman or triple bonds are called unsaturated hydrocarbons because they don't contain as many hydrogen atoms as possible.

Dull compounds

An polyunsaturated compound contains double or triple bonds. A carbon paper spec may therefore be bonded to only two or three other atoms.

Figure 4.13 shows molecules of ethylene and acetylene which are unsaturated hydrocarbons. If you compare the number of carbon paper and H atoms in a molecule of C2H6 and a mote of ethene, you will check that the number of hydrogen atoms in ethene is little than the number of hydrogen atoms in C2H6 disdain the fact that they both contain two carbon atoms. Systematic for an unsaturated hydrocarbon compound to become saturated, one of the two (or three) bonds in a double (Beaver State multiple) bond has to embody broken, and additional atoms added.

Figure 4.13: Dull hydrocarbons: (a) ethylene and (b) acetylene.

The hydrocarbons (ESCK9)

Rent out us first view a group of animate thing compounds known as the hydrocarbons.

Hydrocarbon

An organic molecule which contains only carbon and hydrogen atoms with no more other utilitarian groups also separate, multiple or triple C-carbon bonds.

The hydrocarbons that we are going to look at are known as aliphatic compounds. The aliphatic compounds are divided into acyclic compounds (chain structures) and cyclic compounds (ring structures). The chain structures are further divided into structures that contain only unshared bonds (alkanes), those that contain at any rate unmatchable double draw together (alkenes) and those that contain at least one triple bond (alkynes).

Circular compounds (which will not beryllium covered in this book) admit structures such as a cyclopentane closed chain, which is found in insulating foam and in appliances such A fridges and freezers. Figure 4.14 summarises the classification of the hydrocarbons.

Figure 4.14: The classification of the acyclic hydrocarbons.

An aliphatic compound is one that does not contain an hydrocarbon ring:

The simplest aromatic compound is benzene. There are aliphatic oscillation compounds, but if a compound contains an aromatic ring information technology is an aromatic compound, not an acyclic one.

We bequeath now deal for each one of the acyclic, aliphatic hydrocarbon groups in to a greater extent detail.

The alkanes

The alkanes are hydrocarbons that only check single covalent bonds between their carbon atoms. This means that they are sopping compounds and are quite unreactive. The simplest alkane has entirely one carbon atom and is called methane. This speck is shown in Figure 4.15.

Figure 4.15: The (a) noesis and (b) molecular formula representations of methane.

The indorse alkane in the serial publication has two carbon atoms and is called ethane. This is shown in Figure 4.16.

Figure 4.16: The (a) structural, (b) condensed biological science and (c) molecular formula representations of ethane. (d) An atomic model of ethane.

The third alkane in the series has three atomic number 6 atoms and is titled propane (Figure 4.17).

Figure 4.17: The (a) structural, (b) condensed noesis and (c) molecular expression representations of propane. (d) A three-multidimensional computer generated model of propane.

When you view the building block formula for all of the alkanes, you should discover a form developing. For each carbon atom that is added to the particle, cardinal hydrogen atoms are added. In other words, each molecule differs from the one before it past \(\text{CH}_{2}\). This is known as a homological series.

Homologous serial publication

A homologous series is a serial publication of compounds with the same full general formula. All molecules therein series will contain the same functional groups.

Some fungi economic consumption alkanes Eastern Samoa a source of carbon and energy. One fungus amorphotheca resinae (also known as lamp oil fungus) prefers the alkanes used in air fuel, and this sack grounds problems for aircraft in tropical areas.

The general formula is similar to both the molecular formula and the condensed structural formula. The functional mathematical group is written atomic number 3 it would be in the condensed structural formula (to make IT more obvious), spell the rest of the atoms in the compound are written in the Sami style as the molecular formula. The alkanes have the generalized formula: \(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n+2}}}\).

• The alkanes are the most strategic source of fuel in the reality and are used extensively in the chemic industriousness.

• Alkanes that contain four or less carbon atoms are gases (e.g. methane and ethane).

  

  (a) Methane gas bubbles fervent and (b) propane (under high pressure) organism transported by hand truck.

• Others are liquid fuels (e.g. octane, an important component of gas).

  

  Figure 4.19: Liquid fuels that contain octane are unbroken in tanks at petrol stations.

The alkenes

In the alkenes there must be at least one double bond between two carbon atoms. This means that they are unsaturated and are more reactive than the alkanes. The simplest alkene is ethene (as wel known As ethylene), which is shown in Figure 4.20.

Figure 4.20: The (a) structural, (b) condensed structural and (c) molecular formula representations of ethene. (d) An atomic model of ethylene.

Arsenic with the alkanes, the alkenes also form a homological series. They wealthy person the general formula: \(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n}}}\). The second alkene in the series would hence glucinium \(\text{C}_{3}\text{H}_{6}\). This molecule is known as propene (Frame 4.21).

Figure 4.21: The (a) structural, (b) condensed structural and (c) building block formula representations of propene.

There can be Thomas More than one double slave in an alkene as shown in Figure 4.22. The naming of these compounds is covered in Section 4.3, IUPAC naming and formulae.

Note that if an alkene has two double bonds, it is called a diene.

If you don't understand the name calling of compounds, don't worry. We will go into more detail on this later in the chapter.

Figure 4.22: The structural representations of (a) shut up-1-ene and (b) pent-1,3-diene.

The alkenes are many reactive than the alkanes because they are unsaturated. Equally with the alkanes, compounds that bear quartet or less carbon atoms are gases at room temperature. Those with five or more carbon atoms are liquids.

The alkenes have a variety of uses:

• E.g., ethylene is a compound used in plants to stimulate the ripening of fruits and the opening of flowers.

  

  (a) Unripe (jet) and ripe (icteric) bananas and (b) a flowering plant.

• Propene is an epochal trilobed in the petrochemicals industry. IT is accustomed make polypropylene (see Section 4.7 for more information) and is also used as a fire gas for other industrial processes.

  

  Figure 4.24: A lamp made of polypropene. Propene is used to make polypropylene.

The alkynes

In the alkynes on that point must live at least one ternary bond between cardinal of the carbon atoms. They are unsaturated compounds and are therefore more reactive than alkanes. Their general formula is \(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n-2}}}\). E.g. only-1-yne has the molecular pattern \({\textbf{C}_{4}{\textbf{H}_{6}}}\). The simplest alkyne is ethyne (Figure 4.25), also known as acetylene. Many of the alkynes are put-upon to synthesise other chemical products.

Acetylene is the progressive public figure for the constitutional three-lobed ethyne. The raw materials that are needed to make acetylene are Ca carbonate and coal. An beta use of acetylene is in fueled vaunt welding. The fuel gas burns with O in a torch. Because the burning of alkenes and alkynes is exothermic an improbably high heat is produced, which is hot sufficiency to melt metal.

Figure 4.25: The (a) structural, (b) condensed structural and (c) molecular representations of ethyne (acetylene). (d) An thermonuclear poser of ethyne.

Think of that organic molecules do not need to be directly irons. They can have branched groups likewise, as shown in Estimate 4.26.

Figure 4.26: A methyl pronged group along C 2 of butane (2-methylbutane).

A succinct of the congenator reactivity and the homologous series that pass in the hydrocarbons is given in Table 4.2.

Functional group	Homological series	Reactivity
alk one	\(\color{bolshie}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n+2}}}\)	low reactivity
alk ENE	\(\color{cherry-red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n}}}\)	high responsiveness
alk yne	\(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n-2}}}\)	high reactivity

Set back 4.2: A summary of the homologous series of the hydrocarbons.

Liquid bromine is highly corrosive and toxic. Handle with distant care!

For the experiment on saturated and unsaturated compounds, if cyclohexane and cyclohexene are not available any alkanes/alkenes that are liquids at room temperature are acceptable. These should be relatively easy to source.

Liquid bromine is corrosive and noxious, including the exhaust. If you have to prepare your personal bromine piddle from liquid bromine suffice not Lashkar-e-Tayyiba the learners cover the liquid bromine. Wear full safety gear and do not breath in the exhaust fumes. Bring on in a well ventilated area (preferably a fume hood) and follow careful.

To wee \(\text{50}\) \(\text{ml}\) atomic number 35 water:

• Take a bottle with a capacity of at least \(\text{100}\) \(\textual matter{ml}\) and a lid that closes securely (screw top).

• Label the bottle and place \(\text{50}\) \(\text{mil}\) of water into the bottleful.

• Decant the vapours from a bottle of liquid bromine (with appropriate precautions) into the labelled bottle until the airspace above the pee is altogether full of the mahogany-red gas.

• Cap some bottles and gently purl the bromine water bottle so that the bromine accelerator dissolves in the water.

• Repeat the sue at least one more time, until the water retains an orange colour.

Saturated vs. unsaturated compounds

Object

To study the effect of bromine water and potassium permanganate on soaking and unsaturated compounds.

Setup

Thawed Br (required to make Br water) is a highly vapourific, corrosive and toxic compound. Delight handle with care: wear the appropriate prophylactic clothing including gloves, labcoat, safety specs and mask. Work in a fumehood. If you execute not have the apparatus to handle liquid atomic number 35 safely, use K permanganate only.

• cyclohexane, cyclohexene, atomic number 35 water (\(\text{Br}_{2}(\textbook{aq})\)), K permanganate (\(\text{KMnO}_{4}\)) in an acidic solution

• 4 glass containers (test tubes/beakers/superficial basins), two A4 sheets of paper

• 2 plastic pipettes

Method

1. Label unitary piece of paper A and the other sheet of paper B.

2. Place \(\text{20}\) \(\text{ml}\) of cyclohexane into a container and place the container in writing A.

3. Place \(\text{20}\) \(\text{mil}\) of cyclohexane into a container and place the container in writing B.

4. Repeat steps 2 and 3 with cyclohexene.

5. Take \(\schoolbook{12}\) \(\text{ml}\) of atomic number 35 water and ADHD it to the beaker of cyclohexane connected paper A. Observe any coloration changes.

6. Duplicate footfall 5 with the beaker of cyclohexene on paper A.

7. Take \(\text{12}\) \(\text{ml}\) of \(\text{KMnO}_{4}\) and add it to the beaker of cyclohexane on newspaper B. Observe whatever colour changes.

8. Repeat step 7 with the beaker of cyclohexene in theory B.

Results

Record your results in the table infra.

Colonial	Initial colour	Solution added	Final examination colour
cyclohexane		Br water
cyclohexane		\(\text{KMnO}_{4}\)
cyclohexene		bromine water
cyclohexene		\(\text edition{KMnO}_{4}\)

Cyclohexane is an alkane, cyclohexene is an alkene.

Questions

• Which of these compounds (cyclohexane, cyclohexene) is saturated and which is polyunsaturated?

• What colour changes did you observe with the alkane lobed?

• What colour changes did you observe with the alkene compound?

• Can you suggest a reason for the differences?

Discussion and conclusion

Bromine water and \(\text{KMnO}_{4}\) both have intense colours. Cyclohexane is a saturated, colourless liquid. When bromine water and \(\text{KMnO}_{4}\) are added to the cyclohexane there is no reaction and the solution becomes the colour of the bromine water or \(\text{KMnO}_{4}\).

Cyclohexene is also a washy liquid, but it is unsaturated. This results in a response with Br water and with \(\text{KMnO}_{4}\). Cyclohexene will form a bromoalkane with Br water. Bromoalkanes are colourless liquids and the solution bequeath be colourless - liquid bromine is decolourised by cyclohexene. Similarly \(\text{KMnO}_{4}\) will be decolourised by the cyclohexene.

The hydrocarbons

Textbook Exercise 4.2

What is the dispute between the alkanes, alkenes and alkynes?

Alkanes make only single bonds between carbon atoms, alkenes have at least one double bond between carbon atoms and alkynes have at least one triple bond between carbon copy atoms.

Give the general formula for the alkynes

\(\text{C}_{\text{n}}\text{H}_{2\text{n}-2}\)

unsaturated

the alkenes and alkynes

Which series is the least reactive? Explain why.

The alkanes are the least reactive. The saturated bonds are more excited than the unsaturated double or triple bonds launch in alkenes and alkynes.

\(\text{CHCCH}_{3}\)

\(\text{CH}_{3}\text{CH}_{2}\text{CH}_{3}\)

\(\text{CH}_{2}\text{CHCH}_{3}\)

Fill in the table below:

Compound	Vivid or unsaturated?
\(\school tex{CH}_{3}\text{CH}_{2}\text{CH}_{3}\)
\(\text{CH}_{3}\text edition{CH}_{2}\text{CHCHCH}_{2}\text{CH}_{2}\text{CH}_{2}\schoolbook{CH}_{3}\)
heptane

Compound	Saturated or unsaturated?
\(\text{CH}_{3}\text{CH}_{2}\text{CH}_{3}\)	saturated
	unsaturated
\(\text edition{CH}_{3}\text{CH}_{2}\text{CHCHCH}_{2}\textbook{CH}_{2}\text{CH}_{2}\text{CH}_{3}\)	unsaturated
heptane	saturated
	unsaturated

The alcohols (ESCKB)

An alcoholic beverage is any integrated compound where there is a hydroxyl usefulness mathematical group \((-\text{OH})\) bound to a carbon atom. The general formula for a simple alcohol is \(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n+1}}\textbf{Ohio}}\).

The simplest and most commonly used alcohols are wood spirit and ethanol (Figures Figure 4.27 and Figure 4.28).

Figure 4.27: The (a) geophysics, (b) condensed structural and (c) building block chemical formula representations of methanol.

Figure 4.28: The (a) structural, (b) condensed geomorphological and (c) molecular formula representations of ethanol. (d) An nuclear model of ethanol.

At that place are trine likely types of carbon atoms - primary, secondary and tertiary. A primary carbon copy is attached to exclusively one other carbon atom. A secondary carbon is loving to two other carbon atoms, while a tertiary carbon paper atom is attached to three other atomic number 6 atoms.

Make secure the learners understand the difference between pirmary, secondary and tertiary carbons:

• Primary

  A primary carbon copy is a carbon atom bonded to uncomparable other carbon atom.

• Secondary

  A secondary carbon is a carbon atom bonded to deuce separate C atoms.

• Tertiary

  A tertiary carbon is a carbon atom secure to threesome otherwise carbon paper atoms.

For example:

\(\text{CH}_{3}\text{CH}_{2}\text edition{CH}_{3}\), C 1 and carbon 3 are primary C atoms because they are only bonded to one other carbon molecule. Carbon 2 is a secondary carbon atom because information technology is bonded to two other carbon atoms.

\(\text{C}(\text{CH}_{3})_{3}\text{X}\), The central C atom in this compound is a tertiary carbon atom because information technology is bonded to ternion other carbon atoms.

A chief intoxicant has the hydroxyl (\(-\text{OH}\)) group bonded to a primary carbon atoms. Similarly, a secondary inebriant has the hydroxyl bonded to a secondary carbon molecule and a tertiary alcohol has the hydroxyl bonded to a tertiary carbon atom.

In that respect can comprise a functioning radical attached to these different types of carbon atom. When a hydroxyl radical \((-\text edition{OH})\) functional group is attached to a primary carbon atom it is called a particular alcoholic beverage. For a secondary alcoholic beverage the hydroxyl is bonded to a secondary carbon molecule. When the hydroxyl is secured to a tertiary carbon atom information technology is a tertiary alcohol. Examples are given below.

Figure 4.29: A (a) main (butan-1-ol), (b) secondary (butan-2-ol) and (c) tertiary

(2-methylpropan-2-ol) alcohol.

The alcohols take up a number of different uses:

• methylated spirits is ethanol with methanol added

  

  Methanol is toxic. If ingested it forms acid Zen or formate salts, which damage the central nervous organisation and can cause sightlessness, coma or death.

• all alcohols are toxic, just in low concentrations ethanol can be used in alcoholic drinks

• ethanol is the only alcohol used in alcoholic drinks

• ethanol is used as an industrial solvent

• methanol and ethanol can both be used A a fuel and they burn Sir Thomas More clean than petrol Oregon diesel.

• ethanol is used as a solvent in medical drugs, perfumes and engraft essences

• fermentation alcohol is an antiseptic

The alcohols

Textbook Practice session 4.3

\(\text edition{CH}_{3}\text{CH}_{2}\text{CH}_{2}\text{CH}_{2}\text{OH}\) or \(\text{CH}_{2}(\text{OH})\text{CH}_{2}\text{CH}_{2}\text{CH}_{3}\)

This is a primary alcohol. The hydroxyl (\(-\text{Buckeye State}\)) group is bonded to a carbon atom that is bonded to only one other carbon spec.

\(\textual matter{CH}_{3}\textbook{C}(\text{CH}_{3})(\text{OH})\text{CH}_{3}\) OR \(\text{CH}_{3}\text{C}(\text{OH})(\schoolbook{CH}_{3})\textbook{CH}_{3}\)

This is a tertiary intoxicant. The hydroxyl (\(-\textual matter{Buckeye State}\)) group is bonded to a carbon molecule that is bonded to three former carbon atoms.

\(\text{CH}_{3}\text{CH}_{2}\text{CH}(\text edition{OH})\text{CH}_{3}\) or \(\text{CH}_{3}\text{CH}(\text{Buckeye State})\text{CH}_{2}\textbook{CH}_{3}\)

This is a secondary alcoholic beverage. The hydroxyl group (\(-\text edition{OH}\)) group is warranted to a carbon atom that is bonded to two other carbon paper atoms.

Alkyl halides (ESCKC)

Alkyl halides are hydrocarbons with one hydrogen atom replaced by a halogen atom (F, Cl, Br, I). The alkyl is imputable the fact that a hydrocarbon branched group has the postfix -yl and is one of the three hydrocarbons: alkanes, alkenes or alkynes. These alkyl groups contain one Beaver State more halogen atoms, which leads to the name alkyl group halides. Our focus will be on the alk1 alkyl halides also known as the haloalkanes (or halogenoalkanes) (see Table 4.1).

Figure 4.30: Representations of a halomethane where X can be F, Cl, Br or I: (a) structural, (b) molecular formula, (c) 3-D line drawing, (d) 3-D ball and stick model and e) 3-D quad-filling model.

Figure 4.31: Representations of 2-halopropane where X can be F, Centiliter, Br or I: (a) structural, (b) condensed noesis, (c) unit formula and (d) a glob and stick exemplar.

Note that the halogen corpuscle is named a substituent.

Forecast 4.32: A atomic number atom atomic number 3 a substituent on carbon copy 2 of butane (2-fluorobutane).

Remember the branched chain shown in Visualize 4.26. That branched chain is also titled a substituent.

Substituent

A substituent is an mote or group of atoms guaranteed to a carbon Ernst Boris Chain. This can be an inorganic atom (e.g. halogen) or an alkyl group that is shorter than the main group.

CFC stands for chlorofluorocarbons. Referable their low toxicity and low responsiveness, CFCs were widely used in refrigeration and as propellants in aerosols. However, the low reactivity means that CFCs can get into the upper atmosphere where they are dissolute by UV light and price the ozone layer.

An organic palmate is ever named in accordance with the longest chain of carbon atoms that contains the functional aggroup. If the substituent is an alkyl group it is known as a branched chain.

Some uses of haloalkanes include:

• in fire extinguishers

• as aerosol propellants

• in infrigidation

• generating foamed plastics

• solvents in dry cleaning processes (non actually dry, but no water is required)

Chloroform (\(\text{CHCl}_{3}\)) was exploited as an anesthetic for years. However, aside from causing dizziness, fatigue and headaches, IT was unconcealed to be toxic, often fatally so. Symmetric not-decisive doses tooshie cause equipment casualty to the kidneys and liver. Chloroform can sometimes be found in cough syrups, although not often any longer.

Chloroform

Haloalkanes can contain more than i halogen atom. Chloromethanes are substances that can be used as anaesthetics during operations. One deterrent example is trichloromethane, alias chloroform (Figure 4.33).

Figure 4.33: The (a) structural and (b) molecular formula representations of trichloromethane (chloroform).

Haloalkanes

Textbook Utilisation 4.4

Give the general formula for the haloalkanes with only one halogen atom

\(\text{C}_{\text{n}}\text{H}_{2\text{n}+1}\textbook{X}\) where X is any halogen atom

Are haloalkanes saturated compounds?

Yes

\(\text{CH}_{2}(\text{Br})\text{CH}_{2}\text{CH}_{3}\)

\(\text{CH}_{3}\text{CH}(\text{Cl})\school tex{CH}_{2}\text{CH}_{3}\)

\(\text{CH}_{2}(\text{F})\text{CH}_{3}\)

Carbonyl-containing compounds (ESCKD)

The carbonyl group consists of a carbon atom that is coupled to an oxygen by a twice James Bond (go steady Figure 4.34).

Bod 4.34: A compound containing a carbonyl group.

In Figure 4.34 \(\color{darkgreen}{\textbf{R'}}\) and \(\color{purple}{\textbf{R}}\) are used to present the rest of the atoms in the speck. For example \(\color{purple}{\textbf{R}}\) could represent an alkyl chain, or a hydrogen mote.

Aldehydes and ketones

(a) An aldehyde and (b) a ketone.

If the functional group is on the end of the carbon paper Ernst Boris Chain, the structured compound is called an aldehyde (Figure 4.35 (a)). Being at the end of the chemical chain means that \(\color{darkgreen}{\textbf{R'}}\) or \(\color{purple}{\textbf{R}}\) represents a hydrogen mote. The simplest aldehyde is methanal. The aldehyde containing 4 carbon paper atoms, butanal, is illustrated in Figure 4.36. In this example \(\colorize{purple}{\textbf{R}}\) represents \(\text{H}\) and \(\colour in{darkgreen}{\textbf{R'}}\) represents \(\text{CH}_{3}\text{CH}_{2}\schoolbook{CH}_{2}\).

Note that the condensed structural formula for an aldehyde ends in \(\text{CHO}\) not \(\text edition{COH}\). This is because COH could be confused with the hydroxyl (\(-\text{Ohio}\)) aggroup of an alochol.

Figure 4.36: The (a) geomorphological, (b) condensed structural and (c) molecular formula representations of butanal. (d) An atomic worthy of butanal.

Just about uses of aldehydes include:

• in resins (complete \(\text{6}\) million tons of formaldehyde are produced per year)

• in the production of plasticisers and alcohols used in detergents

• in perfumes and flavourants

If the chemical group group is in the midst of the carbon chain, the imparipinnate is called a ketone (Figure 4.35 (b)). Being in the middle of the chain means that \(\color{darkgreen}{\textbf{R'}}\) and \(\color{royal}{\textbf{R}}\) cannot represent \(\text{H}\). The simplest ketone is propanone (also familiar as acetone, the compound in smash varnish remover), which contains three carbon atoms. The ketone containing 4 carbon atoms, methyl ethyl ketone, is illustrated in Figure 4.37.

Design 4.37: The (a) structural, (b) condensed structural and (c) molecular convention representations of butanone. (d) An atomic model of butanone.

The molecular formulae representations for butanal and methyl ethyl ketone are identical (\(\text{C}_{4}\textbook{H}_{8}\text{O}\)). This is why structural and condensed structural representations are necessary.

Some uses of ketones include:

• as solvents

• in the yield of polymers

• in the output of pharmaceuticals

The general formula for both the aldehydes and ketones can be written as: \(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n}}\textbf{O}}\). This means that they cannot be told apart from their general formula alone. There are more building complex national formulas that allow aldehydes and ketones to be dignified, but they are not covered in this book.

Chemical group acids

Carboxylic acids are organic acids that are defined by having a carboxyl aggroup, written as \(-\textbook{COOH}\). In a radical group a carbon molecule is double-bonded to an oxygen spec (carbonyl group), and IT is also bonded to a hydroxyl group group (\(\color{purple}{\textbf{R}}\)). The simplest carboxylic acid, methanoic acid, is shown in Figure 4.38 and acetic acid is shown in Cypher 4.39.

Visualise 4.38: The (a) structural, (b) condensed morphologic and (c) molecular formula representations of methanoic acid.

Cipher 4.39: The (a) knowledge, (b) condensed structural and (c) molecular formula representations of acetic acid. (d) An nuclear model of ethanoic acid.

Carboxyl acids are widespread in nature. Methanoic superman (alias formic acid) has the formula \(\schoolbook{HCOOH}\) and is found in insect stings. Acetic acid \((\text{CH}_{3}\text{COOH})\), Oregon ethanoic acid, is the briny component of vinegar. More complex constituent acids also have a motle of different functions. Benzoic acid for example, is used as a food protective. Carboxyl acids have the general formula: \(\colour in{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n+1}}\textbf{COOH}}\).

Ethanoic acid force out be produced through the oxidation of ethanol upon exposure to the oxygen in air. This is why wine that is left too long-run can taste acidic. Wine can well go sour if exposed to the oxygen molecules (\(\text{O}_{2}\)) in the aviation, especially if the weather is warm.

Figure 4.40: The oxidation of wine.

A dependable type of ant, called formicine ants, manufacture and secrete formic venomous, which is used to defend themselves against other organisms that power try to eat in them.

The oxidation of ethanol to ethanoic acid give the axe besides be seen in the response of ethyl alcohol with potassium dichromate:

\(2(\text{Cr}_{2}\text{O}_{7})^{2-}(\text{aq}) + 3\schoolbook{C}_{2}\schoolbook{H}_{5}\text{OH}(\text{aq}) + 16\text edition{H}^{+}(\text{aq})\) \(\to\) \(4\text{Cr}^{3+}(\text{aq}) + 3\schoolbook{CH}_{3}\text{COOH}(\text{aq}) + 11\text{H}_{2}\text{O}(\textual matter{ℓ})\)

The colouring material change that occurs is shown in the image below and the following video:

Figure 4.41: The dissimilar colours of potassium bichromate (left) and potassium dichromate and ethyl alcohol (right-hand). Screenshot taken from video by beggar098 on YouTube.

Breathalysers

Read the following extract taken from HowStuffWorks (12/08/13):

The Breathalyzer device contains:

• A system to sample the breather of the suspect

• Two glass vials containing the chemical reaction mixture

• A system of rules of photocells connected to a meter to measure the color change associated with the reaction

To measure alcohol, a suspect breathes into the gimmick. The breath taste is bubbled in 1 vial through a mixture of sulfuric acid, K bichromate, silver medal nitrate and water. The principle of the measurement is founded on the favourable chemical reaction:

\(2\text{K}_{2}\text{Cr}_{2}\textual matter{O}_{7}(\school tex{aq}) + 3\textual matter{CH}_{3}\text{CH}_{2}\text{Buckeye State}(\textual matter{aq}) + 8\text{H}_{2}\schoolbook{SO}_{4}(\text{aq})\) \(\to\)

\(2\schoolbook{Cr}_{2}(\text{SO}_{4})_{3}(\text{aq}) + 2\textual matter{K}_{2}\text{SO}_{4} + 3\text{CH}_{3}\text{COOH}(\text{aq}) + 11\school tex{H}_{2}\text{O}(\text{ℓ})\)

In this reaction:

1. The sulphuric acid removes the alcohol from the air into a fusible solution.

2. The alcohol reacts with potassium dichromate to produce: chromium sulphate, potassium sulfate, acetic acid, water

The silver nitrate is a catalyst, a substance that makes a reaction go faster without participating in IT. The element acid, in addition to removing the alcohol from the air, also might provide the acidic condition needed for this reaction.

During this reaction, the chromatic dichromate ion changes color to the green atomic number 24 ion when it reacts with the alcoholic beverage; the degree of the color change is directly side by side the level of alcohol in the expelled air. To determine the amount of alcohol in that air, the reacted mixed bag is compared to a vial of unreacted concoction in the photocell system, which produces an current that causes the phonograph needle in the meter to displace from its resting place. The wheeler dealer then rotates a knob to bring the acerate leaf back to the resting invest and reads the level of alcohol from the thickening - the more the operator must turn the pommel to return it to rest, the greater the level of alcohol.

Break into groups of deuce-ac or foursome. Inquiry breathalysers and and then report your information to the course.

Make sure to screening the shadowing areas:

• The event of intoxicant on the body

• The effect of alcohol on reaction times

• The origins of the breathalyzer

• The term mouth alcohol and its effect along breathalyser tests.

Esters

Esters will be dealt with in much greater contingent in Section 4.7.

When an alcohol reacts with a group dot, an ester is formed. Most esters have a characteristic smell. In the reaction a atom of water is removed from the cardinal compounds and a new bond is formed between what remains of the alcoholic beverage and the carboxylic acid. A accelerator is required in this reaction, in this case it must be an artificial acid (e.g. \(\text{H}_{2}\text{SO}_{4}\)). An example is shown in Figure 4.42.

Figure 4.42: The formation of an ester and water from an alcohol and carboxylic acid.

The esterification march is reversible with large quantities of water (although information technology can be slow). In an acidic environment the reaction speeds up. Reversible reactions are covered in greater detail in Chapter 8.

The esterification process with wood alcohol and methanoic acid is shown with atomic models in Number 4.43. Esters have the general formula: \(\color{red}{\textbf{C}_{\textbf{n}}\textbf{H}_{\textbf{2n}}\textbf{O}_{\textbf{2}}}\). This general formula can also be applied to carboxylic acids, but the many complex general expression for esters alone is not covered therein book.

Figure 4.43: The esterification process of methanol and methanoic acid to methyl methanoate and water, shown with terzetto-dimensional model kits.

Some common uses for esters are:

• in cosmetics and beauty products because they typically have a daft smell, qualification them good equally conventionalized flavourants and scents

• in nail polish remover and model plane glue

• as solvents for not-water soluble compounds (e.g. oils, resins) because the ester of a specific carboxylic acid will be less H2O soluble than the radical acid

• as plasticisers because esters commode realise a compound little breakable, and more flexible

Chemical group compounds

Textbook Exercise 4.5

What other structural group does a carboxylic acid have in addition to a carbonyl group?

hydroxyl group grouping

What is the main departure betwixt aldehydes and ketones

An aldehyde must have the chemical group group at the end of the carbon copy chain (chemical group carbon corpuscle bonded to a hydrogen corpuscle). A ketone moldiness have the carbonyl group in the middle of the mountain range (carbonyl carbon mote non bonded to a hydrogen atom).

What two reactants are required to make an ester?

alcohol and carboxylic acid

How is acetic acid produced?

Through the oxidation of ethanol.

\(\text{CH}_{3}\school tex{COCH}_{3}\)

ketone

\(\textual matter{CH}_{3}\text{CH}_{2}\text{COOH}\)

carboxylic sulphurous

\(\text{CH}_{3}\text{CH}_{2}\text{CHO}\)

aldehyde

\(\text{CH}_{3}\text{COOCH}_{3}\)

ester

Usefulness groups

Casebook Exercise 4.6

name of the homologous series of:

\(\text{CH}_{3}\text{CH}(\text{CH}_{3})\textual matter{CH}_{2}\text{CH}(\school tex{CH}_{3})\text{CH}_{2}\text{CH}_{3}\)

Each the carbon atoms are secured to the maximal number of other atoms (four) and there are only when hydrogen and carbon atoms in the molecule. Therefore this is an paraffin series.

OR

Suck in the structural formula:

There are only single carbon-carbon bonds, and all the atoms are carbon or hydrogen atoms. Therefore this compound belongs to the alkanes.

national formula of:

\(\textual matter{C}_{\text{n}}\text{H}_{2\text{n}}\)

name of the homologic series of:

esters

structural formula of:

\(\text{CH}_{3}\text{CH}_{2}\text{COOH}\)

Exhaustive the put over by identifying the functional group of each pinnate.

Organic trilobate	Homologous serial
\(\text{CH}_{3}\text{CH}_{2}\text{CH}_{2}\school tex{COOH}\)	carboxylic acid
	ester
\(\text{CH}_{3}\text{CHO}\)	aldehyde
	paraffin series
\(\text{CH}_{3}\text{CCCH}_{2}\text{CH}_{2}\schoolbook{CH}_{2}\text{CH}_{3}\)	alkyne

Hand down the morphological representation of the compounds represented by condensed structural formulae.

• \(\text{CH}_{3}\school tex{CH}_{2}\text{CH}_{2}\text{COOH}\)

  

• \(\text{CH}_{3}\text edition{CHO}\)

  

• \(\textual matter{CH}_{3}\text{CCCH}_{2}\textual matter{CH}_{2}\text{CH}_{2}\schoolbook{CH}_{3}\)

  

Identify the homologous series to which ethyl methanoate belongs?

Esters

Name the two types of reactants used to develop this compound in a chemical response.

alcohol and carboxylic acid

Give the structural formula of ethyl methanoate (\(\text{HCOOCH}_{2}\text{CH}_{3}\)).

Give the name of the homologous serial publication of the organic compound in the reactants.

Draw the structural mental representation:

The organic compound in the reactants has a double carbon-carbon hamper, therefore it is an alkene.

What is the name of the homologous series of the cartesian product?

Draw the structural representation:

The organic compound in the reactants has only lonesome carbon-carbon bonds and No other useable group. Therefore it is an alkane.

Which compound in the reaction is a saturated hydrocarbon?

The product (the alkane), propane.

Isomers (ESCKF)

It is contingent for deuce organic compounds to have the same molecular formula simply a different structural formula. Look at the ii essential compounds that are shown in Figure 4.44 for lesson.

Figure 4.44: Isomers of a 4-carbon organic compound with the molecular formula \(\text{C}_{4}\text{H}_{10}\).

(a) butane and (b) 2-methylpropane.

Some butane and 2-methylpropane (isobutane) are used in camping stoves and lighters.

If you were to count the number of carbon and hydrogen atoms in all compound, you would ascertain that they are the same. They some give birth the same molecular formula \(\text{C}_{4}\text{H}_{10}\), but their structure is diametric and then are their properties. Such compounds are titled isomers.

Isomer

In chemistry, isomers are molecules with the same molecular formula but different structural formula.

Isomers are molecules with the same molecular normal and often (though not always) with the same kinds of chemical bonds between atoms, merely with the atoms arranged differently.

The isomers shown in Figure 4.44 differ only in the location of the carbon atoms. The functional groups are the same only butane has all four carbons in ane chain, patc 2-methylpropane has ternion carbons in the longest chain and a methyl affianced to the second carbon in the mountain chain. Information technology is also possible to rich person positional isomers (Design 4.45). In this case the \(-\textbook{OH}\) functional mathematical group fire be along variant carbon atoms, for example carbon paper 1 for pentan-1-ol, connected carbon 2 for pentan-2-ol or on carbon 3 for pentan-3-ol.

Figure 4.45: The structural and condensed constitution representations of the isomers (a) pentan-1-ol, (b) pentan-2-ol and (c) pentan-3-ol.

Point isomers are also found in esters. If one ester was made from ethanol and hexanoic Elvis and other was made from hexanol and ethanoic acid the two esters produced are isomers (see Forecast 4.46).

Figure 4.46: The structural representations of the isomers (a) ethyl radical hexanoate and (b) hexyl ethanoate.

It is important to mention that molecules need non have the same functional groups to cost isomers. For example propanone (normally titled acetone) and propanal (Figure 4.47) have the same molecular formula (\(\text{C}_{3}\textual matter{H}_{6}\text{O}\)) but incompatible functional groups and properties (Table 4.3). These types of isomers are structural isomers.

Figure 4.47: Two \(\textbook{C}_{3}\text{H}_{6}\textbook{O}\) isomers (a) propanone and (b) propanal.

Name	Working Group	Melting stop (℃)	Boil (℃)	Reactivity
propanone	ketone	\(-\text{95}\)	\(\text{56}\)	less reactive
propanal	aldehyde	\(-\text{81}\)	\(\text{48}\)	more reactive

Board 4.3: Some properties of the isomers dimethyl ketone and propanal.

Heptanoic acid and butyl propanoate (Figure 4.48) are some other example of functional isomers (containing different functional groups). They both have the same molecular rule of \(\text{C}_{7}\school tex{H}_{14}\text edition{O}_{2}\) but receive various functional groups and different properties (Mesa 4.4).

Figure 4.48: The structural representations of the isomers (a) heptanoic blistering and (b) butyl propanoate.

Name	Useable group	Freezing point (℃)	Boiling point (℃)
heptanoic acid	carboxylic acid	\(-\text{7,5}\)	\(\text{223}\)
butyl propanoate	ester	\(-\textbook{89,5}\)	\(\text{145}\)

Mesa 4.4: The different physical properties of the isomers heptanoic acid and butyl propanoate.

Isomers

Textbook Exercise 4.7

Match the organic compound in Column A with its isomer in Column B:

	Column A	Column B
1	\(\text{CH}_{3}\text edition{CH}_{2}\text{CH}_{2}(\text{OH})\)	\(\text{CH}_{3}\text{CH}(\text{CH}_{3})\text edition{CH}_{3}\)
2
3		\(\text{CH}_{3}\text{CH}(\text{OH})\text{CH}_{3}\)

• A1 (\(\text{CH}_{3}\text{CH}_{2}\text{CH}_{2}(\text{Buckeye State})\)) and B3 (\(\text{CH}_{3}\text{CH}(\text{Ohio})\school tex{CH}_{3}\)) are isomers.

• 

  and B1 (\(\text edition{CH}_{3}\text{CH}(\schoolbook{CH}_{3})\text{CH}_{3}\)) are isomers.

• 

  and

  

  are isomers

Have the ketone isomer of butanal:

A ketone requires that the group group is non at the end of the strand. Consequently it must get on carbon paper 2. The isomer must have the same issue of each type of atom: \(\textual matter{C}_{4}\text{H}_{8}\text{O}\)

Give a carboxylic acid that is an isomer of:

The molecule is an ester. A carboxylic acid essential have the \(-\text{COOH}\) functional group. The isomer must own the same number of each type of particle: \(\text{C}_{5}\text{H}_{10}\text{O}_{2}\). So there are iv options (names not required):

Incomparable isomer with no branched methyl groups:

Two isomers that have one branching methyl chemical group:

Unity isomer that has deuce branching methyl groups:

the organic compound represented by the condensed structural formula

Source: https://intl.siyavula.com/read/science/grade-12/organic-molecules/04-organic-molecules-02

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