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- 1. CHAPTER 3 PROPERTIES AND PROPERTIES AND CHEMICAL STRUCTURE OF CHEMICAL STRUCTURE OF MATTER MATTER Presented By: GROUP 2 Velarde Aligo Bantoc Lapastura Lopez
- 2. Explanation; While most liquids become denser in the solid state ice has a unique property of being less dense than liquid water. Water also not easily bail off because of hydrogen bonding among its molecules, a type of intermolecular forces of attraction. Why does ice float on water? How can some insects, like water striders walk on water?
- 3. CONCEPT MAP Understanding Molecular Structure and Interactions Matter exists in different physical states and has unique properties. The properties result from the way the atoms are arranged and/or chemically bonded. Bonded atoms may assume different structures, which define the chemical nature of substances, including polarity.
- 4. LESSON 1: STRUCTURE AND POLARITY OF A MOLECULE Explain how polar and nonpolar bonds form 1 2 4 3 Objectives; Identify the factors that influence molecular polarity Identify the conditions that make a molecule polar or nonpolar Explain the principle”like dissolves like”
- 5. A. REVIEW OF THE BASIC CONCEPTS As described in Chapter 2, matter is made up of atoms, the smallest particles of an element that may exist either independently (e.g., noble gases and some metals) or as components of compounds. Atoms of the same or different elements can combine into molecules or formula units through chemical bonding. Molecules are bonded neutral atoms, and formula units are bonded ions. Ions are charged particles that result when neutral atoms lose or gain electrons. A positively charged ion is called a cation, while a negatively charged ion is called an anion.
- 6. A. REVIEW OF THE BASIC CONCEPTS When forming a chemical bond, atoms either share or transfer their valence electrons to acquire a more stable configuration. Valence electrons - are electrons located in the outermost energy level of an atom. A complete transfer of valence electrons forms an ionic bond, while sharing of electrons between atoms forms a covalent bond. . Compounds that result from ionic bonding are called ionic compounds, and those that result from covalent bonding are called covalent compounds.
- 7. Molecular sizes and shapes, as well as polarity and bond strength, influence the chemical and physical properties of substances. Therefore, one has to know what a molecule looks like. The first step in doing so is to convert the molecular formula to its corresponding Lewis structure, named after its proponent, Gilbert Newton Lewis. A molecular formula shows the actual number of atoms of each element in a molecule. For water, the molecular formula is H₂O; each water molecule is composed of two hydrogen atoms and one oxygen atom. MOLECULAR SHAPE AND POLARITY
- 8. Gilbert Newton Lewis was an American chemist and dean of the College of Chemistry at UC Berkeley until his death in 1946. He served as superintendent of the Bureau of Weights and Measures in Manila, Philippines (1904– 1905). Lewis proposed the "cubic atom arrangement," suggesting each valence electron occupies a corner of an imaginary cube around the atom. GILBERT NEWTON LEWIS 1875 - 1946 The cube arrangement is an excellent starting point to explain the formation of chemical bonds. This is because each atom acquires a complete set of eight valence electrons, which is called an octet.
- 9. THE LEWIS FORMULA OR LEWIS STRUCTURE OF A MOLECULE PROVIDES INFORMATION ABOUT THE RELATIVE LOCATION OF ATOMS, HOW THEY ARE BONDED, AND THE NUMBER OF COVALENT BONDS PRESENT. ANSWER
- 10. Chemists use valence-shell electron-pair repulsion (VSEPR) theory to determine molecular shape from the Lewis structure. VSEPR states that valence electron groups around a central atom arrange themselves as far apart as possible to minimize repulsion. An "electron group" pertains to a number of electrons that occupy a specific region around an atom; it may be a lone pair, a single bond, a double bond, or a triple bond.The groups repel each other, leading to the most stable three- dimensional arrangement that gives rise to the molecular shape. A single, double, or triple bond is considered a bonding group (or electron pair), while a lone pair is considered a nonbonding group (or electron pair). Both bonding and nonbonding groups contribute to electron group geometry. For instance, water and ammonia both have a tetrahedral electron group geometry due to four electron groups, but their molecular shapes differ because water has two bonding and two nonbonding pairs, while ammonia has three bonding and one nonbonding pair.
- 11. A molecular shape refers to the three- dimensional arrangements of atoms or bonding groups around a central atom. The water molecule has a bent molecule shape while ammonia has trigonL pyramidal shape.
- 12. Table 3-2. Features of Molecular Shapes Table 3-2 shows some of these designations and their corresponding electron group geometries. A solid line (-) represents a bond that lies on the plane of the paper. A dashed wedge line (...) stands for a bond behind this plane and away from the viewer. A solid wedge line ( ) indicates a bond that protrudes from the paper toward the viewer.
- 13. The VSEPR theory established that electron groups, separated by well- defined angles agree with experimental measurements on real molecule. For example, experimental measurements confirm the bond angels of methane(CH4) to be 1095°, which is consistent with a testrahedral electron geometry.
- 14. Notice that the molecular shape changes as lone pairs replace one of the bonding electron groups. These lone pairs also affect bond angles since they exert greater repulsion than bonding pairs, resulting in a larger bond angles in the domain of the nonbonding pair and smaller bond angles among the bonding pairs.
- 15. Polar bond results from the unequal sharing of electrons between two atoms with different electronegativities, such as HCI. Electronegativity refers to a bonded atoms relative ability to attract a shared electrons pair toward itself. The Cl atom takes on a partial negative charge (represented by the symbol , while the H atom takes on a partial positive charge (represented by the symbol .
- 16. For polyatomic molecules, both bond polarity and molecular shape determine the overall molecular polarity. A molecule polarity. polar bonds are present and they are arranged in such a way that the bond dipoles do not cancel or nonpolar bonds and lone pairs on the central atom are present, and they are arranged in such a way that they do not cancel each other. SCIENCE CHECK Bond polarity is not the same as overall molecular polarity. A molecule can have polar bonds and still be nonpolar overall.
- 17. The polarity of a molecule depends on its shape, the presence of polar bonds, and the arrangement of these bonds and lone pairs. Nonpolar molecules: These have bonds or lone pairs in the central atom arranged symmetrically so their dipole moments cancel out. For example, carbon dioxide (CO₂) has a linear shape with two polar C=O bonds that cancel each other, making the molecule nonpolar. Polar molecules: These have asymmetrically arranged polar bonds or lone pairs, resulting in a net dipole moment. For instance, water (H₂O) has a bent shape, polar H-O bonds, and lone pairs on the oxygen atom, creating an uneven distribution of charge and making the molecule polar. Molecular shape and the symmetry of bond polarity are key factors in determining overall molecular polarity.
- 18. if the electron group geometry of a molecule is the same as its molecular shape, (i.e., there is no lone pair in the central atom) and the terminal atoms are all the same, then the molecule is nonpolar.
- 19. The polarity of water significantly impacts its physical properties, such as boiling point, melting point, and solubility. Polar molecules dissolve in water, while nonpolar molecules do not, following the principle "like dissolves like." In other words, polar substances dissolve polar substances; nonpolar substances dissolve nonpolar substances.The term "soluble" refers to substances that mix homogeneously, while "miscible" specifically applies to liquids. For instance, oil is immiscible with water due to its nonpolar nature, whereas ethyl alcohol is miscible with water as both are polar molecules.
- 22. OBJECTIVES: Identify and differentiate the types of intermolecular forces of attraction (IMFA) Explane how each IMFA forms between the partivles of a substance. Explain how IMFA affects the properties of substances
- 23. matter can exist in any of the three major phases: solid, liquid, and gas. Forces of attraction between molecules are responsible for the existence of the different phases of matter. These forces of attraction are called intermolecular forces. Intermolecular forces of attraction determine the properties of each phase and the possible phase changes. Intermolecular forces are relatively weaker than intramolecular forces, which exist within a molecule or formula unit. Strong intermolecular forces tend to yield liquids and solids, while weak intermolecular forces favor the formation of gases. Explain how IMFA affects the (IMFA), in combination with the particles' kinetic energy
- 24. GENERAL TYPES OF IMFA the types of intermolecular forces of attraction, arranged from strongest to weakest, are ion-ion, ion-dipole, hydrogen bonding, dipole-dipole, dipole- induced dipole, and induced dipole- induced dipole.
- 25. Ion - Ion Ion-ion interaction exists between ions. This IMFA is based on Coulomb's law, which suggests that the force of attraction between two oppositely charged ions is directly proportional to the magnitude of the charges of the ions but is inversely proportional to the distance between them.
- 26. Ion - dipole Ion-dipole interaction exists between ions and a polar compound. The interaction becomes stronger either as the charge on the ion increases or as the polarity of the molecule increases. A salt (compound), which can dissociate into ions, dissolved in water (a polar substance) exhibits this interaction. A visual representation of the ion- dipole interaction between sodium chloride (NaCl) and water is provided in Appendix G page 316.
- 27. Hydrogen bonding Hydrogen bonding occurs between polar molecules where hydrogen is bonded to highly electronegative atoms like fluorine, oxygen, or nitrogen. This strong interaction, such as between hydrogen and oxygen in water, contributes to water's high boiling point. In ice, hydrogen bonds are more extensive and stronger than thermal motion, organizing water molecules into a uniform structure. This arrangement increases the distance between molecules, resulting in a higher volume and lower density of ice compared to liquid water.
- 28. Dipole- dipole . Dipole-dipole interaction occurs between polar covalent molecules because of the attraction of the partial positive (+) atoms of one molecule to the partial negative (-) atoms of the other molecule. The interaction between sulfur dioxide (SO2) molecule is an example of this IMFA.
- 29. Dipole-induced dipole interaction exists between a polar covalent molecule and a nonpolar covalent molecule. A temporary dipole is created in the nonpolar covalent molecule because of the nearby permanent dipole of the polar covalent molecule. This type of interaction exists between iodine monochloride (ICI), a polar covalent compound, and the nonpolar noble gas xenon (Xe). Dipole- induced
- 30. Induced dipole - induced - dipole Induced dipole-induced dipole interaction or dispersion forces occur primarily among nonpolar substances like CO2,H2,I2 and noble gases. These forces are caused by fluctuations in the electron distribution within molecules or atoms; consequently, these forces are present in all molecules and atoms. Therefore, except for nonpolar substances, at least two types of intermolecular forces are present, one of which is the dispersion force.
- 32. STRENGTH OF IMFA AND PHYSICAL OF MATTER What properties of substances are influenced by IMFA? The physical properties of substances, especially for condensed Experiment No. 2, states (liquid and solid), vary significantly depending on the nature pages 239-241 and strength of the attractive forces among their atoms, molecules, or ions. The following physical properties are influenced by intermolecular forces of attraction: vapor pressure, boiling point, melting point, viscosity, and surface tension.
- 33. STRENGTH OF IMFA AND PHYSICAL OF MATTER The vapor pressure of a substance is the pressure exerted by its vapor state; it indicates a liquid's evaporation rate. Acetone (with dipole-dipole interactions) has a higher vapor pressure than ethanol (CH₂CH₂OH) because of the H- bonding in ethanol. Since dipole-dipole is weaker than H- bonding, acetone has a higher tendency to evaporate than ethanol. This makes acetone more volatile than ethanol.
- 34. The boiling point of a liquid refers to the temperature at which its vapor pressure equals the atmospheric pressure. Moreover, the term normal boiling point is used when the vapor pressure is 1 atmosphere (1 atm). The melting point of a substance refers to the temperature at which its solid and liquid phases coexist in equilibrium. Similarly, the term normal melting point is used at 1 atm.
- 35. Viscosity refers to the resistance to flow of a liquid; whereas surface tension is a measure of the energy required to increase the surface area by a certain unit amount. Water's high surface tension is due to the strong H-bonds holding the molecules tightly together. Thus, light objects like a needle or some insects float if they are placed gently on water because of water's ability to hold them up.
- 36. If all other variables are constant, the strength of London forces increase as molar mass (MM) increases. For example, I2, (MM = 253.81 g / mol) has a higher boiling point than Cl2 (MM = 70.9 g / mol) since the London forces acting between I2 molecules are larger than Cl2 However, substances that form hydrogen bonds have a much higher boiling point, melting point, viscosity, and surface tension than one would predict based on molar mass. Methanol (CH3OH) has a boiling point of 64.7°C while the boiling point of methanethiol (CH3SH) is 5.95°C
- 38. APPLICATION IN MEDICINE AND OTHER COMMON MATERIALS
- 39. Medical implants and prostheses replace missing or injured body parts or improve existing appendages. Examples: artificial pacemakers, cochlear grafts, dental implants, and breast implants. Materials must be inert and durable, with metals being the most common materials. Strength is crucial for durability.Most prostheses are made up of metals, witch offer strong support.Some have metals mixed to subtances.
- 40. The type of breast implant depends on the filler material: saline-filled implants involve ion-dipole IMFA and pose no health risks if they leak, as the body absorbs the saline. Silicon gel-based implants rely on strong covalent networks, making the gel thick, sticky, and elastic, closely mimicking human fat.
- 41. electronic devices and household gadgets, dipole- induced dipole exists. Components of such devices include polar substances like transient voltage suppression diodes and metalloids or semimetals capable of having induced dipole.
- 42. Sports equipment are used for exercise or sports activities and need to be durable, which requires strong intermolecular forces of attraction (IMFA). Construction supplies, on the other hand, must be sturdy to create compact concrete, which involves several types of IMFA, including ion-ion, hydrogen bonding, dipole-dipole, and ion-dipole forces. Concrete is composed of sand, gravel, rocks, water, and cement.
- 44. CARBOHYDRATES CARBOHYDRATES Carbohydrates are the most abundant type of organic macromolecules on earth. These are sugar polymers, and the term "carbohydrate" was coined from the idea "carbon plus water;" meaning "hydrated carbon." Examples of carbohydrates include starch in bread, rice, and pasta; sucrose in sweets and soft drinks; fructose in honey; maltodextrin in sports drinks; glycogen in meat; cellulose in indigestible fiber; and lactose in milk.
- 46. The functions of macromolecules are related to their structures. Carbohydrates have structural and storage functions. They make up the cell walls of plants and bacteria; cellulose in plants, while peptidoglycan in bacteria. Hydrogen bonding strengthens the plant and bacterial cell walls. Furthermore, cellulose is the component of plants that make them difficult to be digested by humans (figure 3-13). cell walls plant cells microfibril cellulose microfibrils in a plant cell wall cellulose molecules glucose
- 47. Lipids are a group of organic molecules in biological systems and are insoluble in water but soluble in nonpolar solvents. They are of two types: those that contain fatty acid (e.g., fats, oils, and waxes) and those that do not (e.g., steroid, cholesterol, and terpenes). Components of a fatty acid include a polar head and a long nonpolar tail. The polar head consists of a carboxyl group. Amphiphilic substances are both water-and fat-loving. Hydrophobic substances are water- fearing. Those described as hydrophilic are water- loving. LIPIDS LIPIDS
- 48. The IMFA involved are hydrogen bonding for the hydroxyl group (-OH) and dipole-dipole for the carbonyl group (C=O). The tail is composed of a long nonpolar hydrocarbon chain; hence, dispersion forces are predominant. Fatty acids are consequently amphiphilic because they have both a polar and a nonpolar end.
- 49. Several types of IMFA exist in a fatty acid molecule. But which determines the overall characteristics of the molecule? From figure 3-14, the main IMFA is expected to be London forces, specifically between the nonpolar tails since the nonpolar hydrocarbon tail is much more prominent than the small polar head.
- 50. Fatty acids spontaneously form micelles (figure 3-15) when immersed in a polar substance since the fatty acids' polar heads can interact with a polar medium such as water via hydrogen bonding or dipole-dipole interaction; and the nonpolar tails can interact with another nonpolar substance or with another nonpolar tail.
- 51. Babylonians were the first to make soap around 2800 BCE, but it was the Romans who named it "soap" after Mount Sapo, where a legend states that animal fats combined with ash in the river helped clean clothes. Initially, soap was not for bathing. In the second century, the Greek physician Galen suggested soap for cleansing. During World War I, soap's use for cleaning wounds grew and led to the development of synthetic compounds for detergents. Soap-making has since evolved significantly. SCIENCE HISTORY SCIENCE HISTORY HISTORY OF THE HISTORY OF THE SOAP MAKING SOAP MAKING
- 52. When grease or oil ( nonpolar substances )mixes with soap-water solution, fatty acids in soap help connect polar water and nonpolar grease or oil. Soap acts as an emulsifier. An emulsifier allows normally immiscible liquids to mix. Oil, which attracts dirt, does not spontaneously mix with water. When soap is mixed with water, the fatty acid molecules arrange themselves into micelles. Soap molecules form micelles, with hydrophilic parts facing water and hydrophobic parts inside, trapping dirt or oil for easy washing.
- 53. Nucleic acids are macromolecules composed of several nucleotides. A nucleotide, such as the DNA nucleotide shown in figure 3-16, is made up of a nitrogenous base, a sugar, and a phosphate group. The main chain of nucleic acids consists of a sugar- phosphate backbone; the side chains consist of nitrogenous bases. NUCLEIC ACID NUCLEIC ACID
- 54. IMFA between nitrogenous bases determine the folding of the sugar-phosphate backbone to yield a specific conformation, such as the double helix in DNA (deoxyribonucleic acid), providing a framework for the overall three-dimensional shape of nucleic acids. H-bonding predominates in nitrogenous bases, of which there are five: adenine (A), guanine (G), cytosine (C), uracil (U), and thymine (T). Adenine - can form two hydrogen bonds with either thymine or uracil. Guanine - can form three hydrogen bonds with cytosine; hence, a nucleic acid rich in G-C nucleotides is more resilient. The stability of the double helix structure of DNA arises from the H-bonding of base pairs (figure 3-17). Stability increases in proportion to the number of G- C pairs. Melting temperature also rises as stability increases. The genetic information of organisms, defined by nucleic acid sequences, are protected by the high stability of the helix.
- 55. Proteins are the most abundant type of molecules in the body. Each protein performs a specific function, which may be in catalysis, muscle contraction, gene regulation, hormone regulation, immunity, structure, and transport. Amino acids are the building blocks of proteins PROTEINS PROTEINS
- 56. The carboxyl group has hydrogen bonding and dipole-dipole interactions, while the amino group has hydrogen bonding. Side chains can show different attractions based on their type. Nonpolar side chains can have hydrophobic interactions; those with hydroxyl or amines that are uncharged can have hydrogen bonding; charged side chains can have ion-ion interactions; and polar uncharged side chains can have dipole-dipole interactions.
- 57. Proteins have four levels of structures. The primary structure is maintained by peptide bonds, which are intramolecular forces between constituent amino acids. Inter-molecular forces apply to the second, third, and fourth structural levels. H-bonding stabilizes the secondary structure of proteins. For the tertiary and quaternary structures, ion-ion interactions exist. Without these IMFA in proteins, the skin, hair, nails, and cartilages would be easily friable.
- 58. SCIENCE CAREER SCIENCE CAREER X-RAY CRYXTALLOGRAPHY X-RAY CRYXTALLOGRAPHY AND COMPUTATIONAL AND COMPUTATIONAL CHEMISTRY CHEMISTRY Many sophisticated methods are now employed to further study matter. These include X-ray crystallography and computational chemistry. X-ray crystallography uses diffracted X-rays to find the arrangement of atoms in a crystal. It provides details like planarity, bond length, distances between atoms, stereochemistry, and a 3D view of electron density. A DNA sample can be analyzed for its structure through X-ray crystallography. Computational chemistry is an approach that uses equations to summarize the behavior of matter on an atomic scale. It utilizes computers and softwares to solve the equations.
- 59. CHAPTER REVIEW CHAPTER REVIEW Lewis structure is a two-dimensional "blueprint" of molecular shape. It provides information about the relative location and connectivity of atoms, and the covalent bonds in a molecule. VSEPR theory is an essential tool to predict molecular shape from the Lewis structure. Molecular shape refers to the three-dimensional arrangement of atoms or bonding groups around the central atom. Molecular polarity for diatomic molecules is influenced solely by both bond polarity, which in turn, is affected by electronegativity differences of bonded atoms.
- 60. The arrangement of IMFA from strongest to weakest is as follows: ion-ion, ion-dipole, H-bonding, dipole-dipole, dipole-induced dipole, and dispersion forces. Boiling point, melting point, viscosity, and surface tension are directly proportional to the strength of IMFA, while vapor pressure is inversely related to IMFA strength. There are several practical applications of IMFA, including the use of prostheses, implants, sports equipment, and electronic devices. IMFA plays a vital role in the structure and function of biological macromolecules. CHAPTER REVIEW CHAPTER REVIEW
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