Chemistry Chapter on Soaps and Bonds

Soaps and Detergents - Cleansing Action of Soap

• Soap molecules form spherical micelles when added to water.
• The non-polar, hydrophobic tail of the soap molecule attracts dirt/oil.
• The polar, hydrophilic head of the soap molecule attracts water molecules.
• Agitation helps micelles carry dirt/oil particles away from fabric fibers.

Hard Water

• Hard water contains salts of calcium and magnesium (primarily bicarbonates, chlorides, and sulfates).
• When soap is added to hard water, insoluble precipitates of calcium and magnesium salts form.
• These precipitates stick to the fabric, hindering the cleaning ability of the soap.

Covalent Bonds

• Carbon atoms achieve stability by sharing electrons, forming covalent bonds instead of gaining or losing electrons.
• Four valence electrons are shared to form covalent bonds.

Ionic Bonds

• Ionic bonds involve the transfer of electrons between a metal and a nonmetal.
• Electrostatic attractions between oppositely charged ions hold the compound together.
• Ionic compounds are typically crystalline solids with high melting and boiling points.

Lewis Dot Structures

• Lewis structures, also known as electron dot structures, show the element's symbol with dots representing valence electrons.

Covalent Bonding in H₂ , N₂ and O₂

• Atoms share electrons to form covalent bonds.
• Hydrogen (H₂) forms a single bond by sharing one electron each.
• Oxygen (O₂) forms a double bond by sharing two electrons each.
• Nitrogen (N₂) forms a triple bond by sharing three electrons each.

Single, Double and Triple Bonds

• Single bonds share one pair of electrons.
• Double bonds share two pairs of electrons.
• Triple bonds share three pairs of electrons.
• Triple bonds are stronger and shorter than double bonds, which are stronger and shorter than single bonds.

Covalent Bonding of N, O with H and Polarity

• In ammonia (NH₃), nitrogen forms three covalent bonds with hydrogen.
• Nitrogen is more electronegative than hydrogen, pulling the shared electrons closer, creating a polar bond.
• In water (H₂O), oxygen forms two covalent bonds with hydrogen.
• Oxygen is more electronegative than hydrogen, pulling the shared electrons closer, creating a polar bond with a partial negative charge on oxygen and a partial positive charge on hydrogen.

Covalent Bonding in Carbon (Methane)

• Methane (CH₄) is formed when four hydrogen atoms share electrons with a central carbon atom.

### Mp, Bp, and Electrical Conductivity of Covalent Compounds

• Covalent compounds (e.g., gases, liquids, solids) have weak intermolecular forces.
• They have low melting and boiling points, are generally poor electrical conductors, and often soluble in nonpolar liquids.

Allotropes of Carbon

• Allotropes are different physical forms of the same element (e.g., diamond, graphite, fullerenes).

Diamond

• Diamond has a strong, rigid structure with high density and refractive index.
• It's a poor conductor of electricity.

Graphite

• Graphite has a layered structure with weak intermolecular forces, resulting in a soft, slippery feel.
• Graphite is a good conductor of electricity.

C₆₀

• C₆₀, also known as Buckminsterfullerene, is a stable form of carbon.

Chains, Branches and Rings

• Carbon can form chains, branched chains, and rings of hydrocarbons.
• Saturated hydrocarbons have only single bonds.
• Unsaturated hydrocarbons have double or triple bonds.
• Structural isomers have the same molecular formula but different structures.

Benzene

• Benzene has a cyclic structure with alternating double and single bonds.
• It exhibits resonance—multiple stable structures.

Functional Groups

• Functional groups are atoms or groups of atoms that determine the chemical properties of a compound. -Examples: Hydroxyl(-OH), Aldehyde (-CHO), Ketone (-C=O), Carboxyl (-COOH) -Others: Halogen (F, Cl, Br, I).

Homologous Series

• Members of a series have similar chemical properties due to the same functional group.
• Physical properties change predictably with increasing molecular mass.

Combustion Reactions

• Combustion involves burning a hydrocarbon with oxygen to produce carbon dioxide, water, heat, and light.
• Saturated hydrocarbons burn to produce a cleaner flame than unsaturated hydrocarbons.

Oxidation

• Mild oxidizing agents (e.g., chromic anhydride) oxidize ethanol to ethanal.
• Strong oxidizing agents (e.g., acidified potassium dichromate or alkaline potassium permanganate oxidize ethanol to ethanoic acid.

Addition Reactions

• Addition reactions involve the combining of two molecules to form a single product.
• Hydrogenation, where hydrogen is added to unsaturated molecules in the presence of a catalyst, is an example.

Substitution Reactions

• Substitution reactions involve replacing one atom or group of atoms with another.
• An example is replacing hydrogen atoms in methane with chlorine atoms.

Ethanol and Ethanoic Acid

• Ethanol is a colorless liquid, miscible with water, and neutral to litmus.
• Ethanoic acid (acetic acid) is a carboxylic acid that is miscible with water, and is acidic and its glacial form freezes easily.

Elimination Reactions

• Elimination reactions involve the removal of substituents from a molecule.

Dehydration Reactions

• Dehydration reactions involve the removal of water molecules.
• An example is the dehydration of ethanol to produce ethylene.

Esterification

• Esterification is the reaction between a carboxylic acid and an alcohol to produce an ester and water.
• Esters have fruity or sweet smells.

Saponification

• Saponification is the alkaline hydrolysis of oils and fats to form soap and glycerol.

Reaction of Ethanoic Acid with Metals and Bases

• Carboxylic acids (e.g., ethanoic acid) react with metals and bases.
• The reactions release hydrogen gas or form salts depending on the base.

Friendly Carbon

• Carbon's ability to form a large number of compounds is due to catenation, tetravalency, and its ability to form multiple bonds.
• Catenation is the ability of carbon to bond to itself to form chains, branches or rings, resulting in a vast array of molecules.

Explore the fascinating world of soaps, their cleansing action, and the effects of hard water on cleanliness. This quiz also delves into the fundamental concepts of covalent and ionic bonds, providing a comprehensive understanding of chemical interactions. Test your knowledge on how these concepts play a role in everyday life.