Lesson 2 Chapter 1 – Chemical Principles

Lesson 2 Chapter 1 – Chemical Principles Unit 1 Study Guide Chemical Principles 1. Matter – anything that occupies space and has mass 2. States of matter – solid, liquid, gas o Solid – has definite shape and volume o Liquid – has no definite shape and definite volume o Gas – has no definite shape and no definite volume 3. Energy – the capacity to do work or put matter into motion o Kinetic energy – energy in action o Potential energy – stored energy; has the capability to do work but is not now 4. Forms of energy o o o o Chemical – stored in the bonds of chemical substances (food molecules, ATP) Electrical – movement of charged particles Mechanical – energy directly involved in moving matter Radiant – energy that travels in waves (electromagnetic spectrum) 5. Unit o Matter – anything that occupies space and has a mass o Mass – the amount of matter o Weight – the effect of gravity on that mass All forms of matter are made up of chemical elements (atoms) – – Most common – H, C, O, N (96% of body elements) 4% - minerals With each element made up of atoms. Atoms are the smallest unit of matter with 3 subatomic particles: neutrons, protons, and electrons. 1 Lesson 2 Chapter 1 – Chemical Principles There is a difference between the meanings of atomic mass and mass number. One is the average weight of an element and the other is the total number of nucleons in the atom's nucleus. Atomic mass is also known as atomic weight. Atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes. Mass number is a count of the total number of protons and neutrons in an atom's nucleus. Atomic number = number of protons in an atom Element = pure substances with same atomic number Mass number (atomic weight/mass) = total number of protons and neutrons Isotopes of an element = atoms of an element with same number of protons but different number of neutrons Electrons Electron shells = number of electrons in its outermost shell • • • • innermost shell can hold 2 electrons second shell can hold 8 electrons third shell can hold 18 electrons (but most elements require 8 electrons to complete the outermost shell) Electrons form bonds between atoms 2 Lesson 2 Chapter 1 – Chemical Principles 3 Chemical Bonds The two main types of bonds formed between atoms are ionic bonds and covalent bonds. o An ionic bond is formed when one atom accepts or donates one or more of its valence electrons to another atom. o A covalent bond is formed when atoms share valence electrons. The atoms do not always share the electrons equally, so a polar covalent bond may be the result. When electrons are shared by two metallic atoms a metallic bond may be formed. In a covalent bond, electrons are shared between two atoms. The electrons that participate in metallic bonds may be shared between any of the metal atoms in the region. If the electronegativity values of two atoms are:   Similar... o Metallic bonds form between two metal atoms. o Covalent bonds form between two non-metal atoms.  Nonpolar covalent bonds form when the electronegativity values are very similar.  Polar covalent bonds form when the electronegativity values are a little further apart. Different... o Ionic bonds are formed. Ion • • • Atoms can become ions (ionization) – when interacting with other atoms – when an atom gains or loses one or more electrons Ionization – the process of giving up or gaining electrons Ion – an atom that has a positive charge (cations) or negative charge (anions) Lesson 2 Chapter 1 – Chemical Principles 4 Lesson 2 Chapter 1 – Chemical Principles 5 Hydrogen bonds: The attraction between slight positive hydrogen ion and electronegative atom like oxygen or nitrogen. Simply put, Molecule - combination of two or more atoms held together by chemical bonds When the two atoms are identical the resulting substance is called a molecule of that element (H2 is a molecule of hydrogen gas). Compound – when two or more different kinds of atoms bind they form molecules of a compound; chemically pure; all molecules identical (H2O is a compound – it is a molecule of water). Mixtures – substances composed of two or more substances physically intermixed. Inorganic vs Organic compounds The primary difference between organic compounds and inorganic compounds is that organic compounds always contain carbon while most inorganic compounds do not contain carbon. Also, almost all organic compounds contain carbon-hydrogen or C-H bonds. 1. Organic compounds are the result of activities of living beings while inorganic compounds are created either due to natural processes unrelated to any life form or the result of human experimentation in the laboratory. 2. Inorganic compounds can make salt, while organic cannot. 3. Organic compounds contain carbon, while inorganic do not. 4. Organic compounds have carbon-hydrogen bonds, while inorganic do not. 5. Inorganic compounds contain metal atoms, whereas organic compounds do not. 6. Organic compounds are biological and inorganic are mineral in nature. 7. Organic compounds are part of a class of chemical compounds the molecules of which contain carbon and hydrogen, while inorganic compounds mostly comprise of metal containing compounds even if they happen to exist in living organisms. Lesson 2 Chapter 1 – Chemical Principles 6 Examples of Organic Compounds or Molecules Molecules associated with living organisms are organic. These include nucleic acids, fats, sugars, proteins, enzymes and many fuels.     DNA table sugar or sucrose, C12H22O11 benzene, C6H6 methane, CH4 Examples of Inorganic Compounds Inorganics include salts, metals, substances made from single elements and any other compounds that don't contain carbon bonded to hydrogen.    table salt or sodium chloride, NaCl carbon dioxide, CO2 diamond (pure carbon) Solutes Solutions – homogeneous mixtures of components that may be gases, liquids, or solids. [air, seawater] • Solution: solute dissolves in solvent Solvent – substance in a solution present in the greatest amount (dissolving medium) [water] • Solvents dissolve solutes Solute – substance in a solution present in smaller amounts (thing that is dissolved) [salt] • Solutes dissolve in liquids – charged ions in water – conduct electricity – called “electrolytes” Solubility, ease of dissolving – – Hydrophobic • insoluble in water, repelled by water molecules • non polar covalent bonds - hydrocarbon chain of fat molecules Hydrophilic • water soluble • polar covalent bonds - glucose, amino acids Lesson 2 Chapter 1 – Chemical Principles 7 Biomolecules are molecules that are synthesized by living organism and contain carbon atoms. 4 basic types of biomolecules are: • • • • Carbohydrates Lipids Proteins Nucleotides Carbohydrates include sugars and starches. They are composed of carbon, hydrogen, and oxygen. Monosaccharides are simple sugars, example glucose (the major fuel source for the body). Disaccharides are composed of two sugar units, for example table sugar or sucrose (glucose + fructose). Polysaccharides are composed of many sugar units, for example starch (the storage carbohydrate of plant tissues) and glycogen (the storage carbohydrate of animal tissues). The primary function of carbohydrates in the body is to serve as a source of cellular fuel. Lipids are insoluble in water, but dissolve readily in other lipids and organic solvents like alcohol. Lipids include neutral fats, phospholipids, and steroids. Tryglycerides are neutral fats, composed of a backbone of glycerol with three attached fatty acid chains. Neutral fats provide the body’s most efficient and compact form for storing usable energy fuel. Phospholipids are similar to triglycerides except one fatty acid chain is replaced by a phosphate group. Phospholipids compose a large part of cellular membranes. Steroids are flat molecules made of interlocking hydrocarbon rings. An example of cholesterol which is a building block of Vitamin D, steroid hormones, and bile salts. Proteins are composed of building blocks called amino acids joined by peptide bonds. There are 20 different amino acids in biological proteins. Proteins serve as the major structural material in the body and also as enzymes. Proteins may fold up into distinct shapes via intramolecular hydrogen bonding. The protein usually must maintain its proper three-dimensional shape in order to function. Fibrous proteins such as collagen make up a large part of connective tissue. Globular proteins include hormones and enzymes. Enzymes are biological catalysts – substances that regulate and accelerate the rate of biochemical reactions but are not used up or changed in those reactions. Basically enzymes help the biochemical reactions of our body to proceed at a rate that supports life. Nucleic acids such as DNA and RNA are composed of chains of nucleotides made up of a phosphate, sugar, and nitrogen-containing base. DNA (deoxyribonucleic acid) is the genetic material. A chromosome consists of a molecule of DNA. Certain segments of DNA are known as genes. A gene provides the instructions for how to make a single protein chain. RNA (ribonucleic acid) assists in gene expression by carrying the code for a protein to the place in the cell that proteins are manufactured. ATP (adenosine triphosphate) is a nucleotide which serves as the energy carrier molecule in the cell.