Introduction to Basic Chemistry Allorganisms (living things) are composed of chemicals. •The study of these chemicals & how they react in living organisms is called biochemistry Introduction to Chemistry • The smallest components that make up cells are atoms. • Atoms are “pure”, meaning they are only made up of one kind of substance or element. atomos “unable to be cut”. Has 3 subatomic particles 1.neutrons (no charge) 2.protons (+) 3.electrons (-) arranged in levels (shells) Protons & neutrons have approx. the same mass and comprise the nucleus. Electrons are 1/1840th the mass of a neutron and travel constantly in the space around the nucleus (the electron cloud) Name coined by John Dalton in 1805. The Electron Cloud The electrons travel at almost the speed of light. They create a “cloud” around the nucleus. More Important Info. Atomsthat combine chemically create molecules. Periodic Chart 118 elements are represented on the newest periodic table of elements. Elements are represented by one or two letter symbol. Ex. Carbon (C), Helium (He) Elements song; http://www.youtube.com/watch?v=GFIvXVMbII0&feat ure=related Element Information The element info. is not always in the same order within the element box. Element Information: Fill in A= atomic number (# protons) ion charge(s) (electron B= affinity) C= Element symbol D= Element name E= Atomic mass (protons + neutrons) – Elements (and symbols) – Atomic Number (# of protons) – Atomic Mass (# of protons + neutrons) – Phase of Element at Earth temperature – Affinity for giving or taking electrons http://www.teachersdomain.org/resource/lsps07.sci.phys.matter.theatom/ “CHNOPS” -97% of the compounds present in living organisms contain these 6 elements. Electrons • All atoms are neutral so the # of protons (the atomic number) is equal to the # of electrons. # of P = # of E Energy Levels of Atoms • ORBITAL BASICS 1. An electron shell is sometimes called an orbital or energy level. 2. Shells are areas that surround the nucleus of an atom. 3. Electrons are found on the energy shells. 4. Each of those shells (levels) has a name. • • There are a couple of ways that atomic orbitals are named. Chemists use letters to name the orbitals around a nucleus. They use the letters "k,l,m,n,o,p, and q". • The "k" shell is the one closest to the nucleus and "q" is the farthest away. • The further from the nucleus, the more energy the electron has. # Of Electrons In Each Shell • Not all shells hold the same number of electrons. For the first eighteen elements, there are some easy rules. Electrons and Energy Levels • The first shell is located closest to the nucleus and can hold a maximum of 2 electrons (e-) or Hydrogen Helium # Of Electrons In Each Shell • The 2nd shell (l-shell) only holds a max. of eight electrons. • The 3rd shell (m-shell) only holds a max. of eight valance electrons (for the first eighteen elements). The m-shell can actually hold up to 8 valance and 10 sub- active electrons • The maximum number of electrons you will find in any shell is 32. • Using your Orbital handout, draw the appropriate # of electrons on the orbital(s) for the first 18 elements. Remember: • you must fill the first orbital (with 2 e-) before you can go to the second orbital. • You must fill the second orbital (with 8 e-) before you can go to the 3rd orbital. The answers are: This way of drawing the electrons is called the Electron Dot Formula When using the Lewis Dot Formula, you only show the electrons in the outer most shell. These are called VALANCE electrons. ISOTOPES 1. Variation in # of neutrons of an element 2. Changes mass number 3. Can be radioactive Nuclei are unstable and break down at a constant rate over time Example: Non-radioactive carbon-12 (6e-, 6 p+, 6n). Non-radioactive carbon-13 (6 e-, 6 p+, 7n). Radioactive carbon-14 (6 e-, 6p+, 8n) All isotopes of an element have the same chemical properties (because they all have the same # of e- and protons+) Uses of Radioactive Isotopes 1. To study living systems/processes ex: Radioisotopes can be used to help understand chemical and biological processes in plants. (radioactive water) Uses of Radioactive Isotopes 2. Diagnose and treat disease (nuclear medicine) a) Tracers: Bone scans can detect the spread of cancer six to 18 months sooner than X-rays by using a PET scan, for ex. FYI: The most common tracer is a radioactive version of glucose. When this is injected into your body it travels to places where glucose is used for energy. It shows up cancers because they use a lot of glucose. It will also be taken up by normal tissues which use glucose for energy, for example the brain, and as a result of other abnormalities such as infection. The PET scan shows cancerous hot spots. In other words, cancer tumors light up. Uses of Radioactive Isotopes 2. Diagnose and treat disease (continued) b) Drug Testing: One of the main tests is to determine if the pharmaceutical is going to other parts of the body than the intended target and what effect it has on the non-target areas. By adding a radioactive tag to the pharmaceutical, researchers can pinpoint all parts of the body and the concentration that accumulates in non-target areas. From this they can determine if there is likelihood of adverse reactions in other parts of the body. Uses of Radioactive Isotopes continued 3. sterilize food: Food irradiation is a method of treating food in order to make it safer to eat and have a longer shelf life. Food irradiated by exposing it to the gamma rays of a radioisotope -- one that is widely used is cobalt-60. The energy from the gamma ray passing through the food is enough to destroy many disease-causing bacteria as well as those that cause food to spoil, but is not strong enough to change the quality, flavor or texture of the food. Uses of Radioactive Isotopes http://www.youtube.com/watch?v=31-P9pcPStg continued calculate the age of certain rocks 4. and fossilized organisms: Ions • Your whole goal as an atom is to become a "happy atom" with completely filled electron orbitals. • Sometimes that means you need to give up some electrons or maybe gain some electrons Rule • Atoms that have 1, 2 or 3 electrons in the outer most shell, will GIVE THEM AWAY! • Atoms that have 5, 6 or 7 electrons in the outermost shell will steal electrons from other atoms! Ionic Bond • Now, Na+ and Cl- are attracted to one another because….OPPOSITES ATTRACT! NaCl is now neutral and makes up what we commonly call…. TABLE SALT! For example: • O----------- O2- Adding 2 more electrons will give Oxygen a full outermost shell but it will also make oxygen have a negative charge (since it now has 10 electrons but still only 8 protons). Make these atoms into ions • Be Be 2+ • F F- • Al Al 3+ • Mg • S Mg 2+ S 2- Have you ever heard of electrolytes? • Electrolyte is a "medical/scientific" term for salts, specifically ions. • Electrolytes are important • The term electrolyte means that because they are what your this ion is electrically-charged. cells (especially nerve, • For example, your body fluids -- heart, muscle) use to blood, plasma, interstitial fluid maintain voltages across (fluid between cells) -- are like their cell membranes and to seawater and have a high carry electrical impulses concentration of sodium (nerve impulses, muscle chloride (table salt, or NaCl). contractions) across themselves and to other cells. http://www.us.powerade.com/ The major body electrolytes are as follows: sodium (Na+), potassium (K+), chloride (Cl-), calcium (Ca2+) magnesium (Mg2+), bicarbonate (HCO3-), phosphate (PO42-), sulfate (SO42-) Compounds Compounds are groups of two or more elements that are bonded together. There are two main types of bonds that hold those atoms together: Ionic compounds happen when electrons are donated from one atom to another. Atoms that have 1, 2, 3, 5, 6 or 7 electrons in their outermost orbital (except for the first level) tend to transfer electrons forming ions. Covalent compounds happen when the atoms share the electrons. Atoms that have 4 or 5 electrons in their outermost orbital tend to share electrons making covalent compounds. Covalent Bonds A chemical bond formed by the sharing of electrons in the outermost shell of both (all) atoms. Atoms change their physical and chemical properties when they form a compound via covalent bonding. Covalent bonds can be single (one pair of electrons is shared) double (two pairs), triple (three pairs), quadruple (four pairs) Let’s take a look…. NaCl and H2O http://www.youtube.com/watch?v=yjge1 WdCFPs Water • 1 Oxygen and 2 hydrogen share their outermost electrons so each can have a full outermost shell. H H O Water can also be written as above. The single line represents a single bond. Molecules • Molecules are made up of atoms that have been chemically combined. H2O • Molecules may be made from: • more than one type of atom (Ex. H2O), or • atoms of the same type. (Ex. Hydrogen covalently bonds to one another and is found naturally in pairs; H2) • The number of atoms in each element in a molecule is shown by a subscript following the symbol for the element. Ex. CO2 (one carbon, 2 oxygen) • Water can be broken down into two very different substances, hydrogen and oxygen. • Hydrogen and oxygen are elements (substances that cannot be broken down chemically into simpler substances). Single Bonds: one, two, three, or four H H F2 More Covalent bonds Double: 2 pairs of electrons are being shared Triple bond: 3 pairs being shared • Quadruple bond : two carbon atoms C C Lewis Dot Structure • When drawing the electrons using the Lewis Dot Formula, you do not draw the outer ring. • When showing a bond, you only use a line. This is illustrating Atom 1 Atom 2 how to show the bond between two oxygen atoms. • Relatively weak attractive forces between electrically neutral atoms and molecules. • These forces are not as strong as ionic bonds or covalent bonds. • They can hold together and create a “sticky” or adhesive property. • Ex. Geckos walking up a glass Atoms, Molecules, and Compounds Water may vary between gas, liquid and solid while keeping the same chemical composition. All living things are composed of approximately 70 to 80% water. Water has some unusual physical & chemical properties that have had a powerful effect on the evolution of life. (we’ll talk about that later) Hydrogen Bonding • Polarity: an uneven sharing of electrons. Hydrogen Bonding The negative part of one water molecule will attract the positive parts of other, nearby water molecules. This is why water falls from the sky as raindrops, and not individual molecules, or why water tends to bead up on the hood of your freshly waxed car, or why you can cause water to bulge out over the rim of a glass if you fill it carefully; the molecules are all pulling together. Cohesion and Adhesion of Water Molecules • In hydrogen bonding, water sticks to other water molecules. This is called COHESION. • Water molecules are also attracted to other polar substances causing them to adhere to many kinds of materials. • Water sticking to other substances is ADHESION. Surface Tension The water molecules bond together at the surface creating a surface "film“ or tension. But those on the surface have no neighboring atoms The cohesive above, and exhibit forces between stronger attractive molecules down forces upon their into a liquid are nearest neighbors shared with all on the surface. neighboring atoms so they’re not so strong. This enhancement of the attractive forces at the surface is called surface tension. Soaps and detergents lower the surface tension of the water (breaking the surface tension much quicker). Things that could walk on the surface cannot if the water becomes soapy or polluted. Washing your hands: Soap molecules are attracted to both water and oil. One end of the soap molecule sticks to oil, the other end sticks to water. The soap breaks up the surface tension and keeps the oil drops mixed in with the water so that the oil can wash off your hand. Adhesion or Cohesion? • Adhesion – water sticking to the sides of the glass • The photograph below shows water on the roof of a waxed car. The water molecules cling to each other but not to the waxed surface because the wax is non-polar. Adhesion or Cohesion? COHESION • This water strider is able to remain on the surface of water because of hydrogen bonding between the molecules. The insect is light and it’s weight is spread over the water so that there is not much weight at any one point. The Jesus Lizard: http://www.youtu be.com/watch?v= 45yabrnryXk Polar vs. Non-polar: Ions and Polar Molecules Dissolve in Water • One reason polarity is important is because water can bond to other polar molecules; hence water is often called the universal solvent. A good example of this Oil and water is the addition do not mix of sugar to because oil is water. Because non-polar and sugar is also a therefore polar molecule, doesn’t have the positive end of the water a positive or joins to the negative negative end of side. sugar and vice versa. Exception to the Rule • Salt is an example of an exception to this. Salt is a non-polar molecule, yet water can dissolve it. • Salt dissolves in water because it breaks down into ions in solution. It becomes Na+ and Cl- ions that the water molecules attach to. http://www.youtube.c om/watch?v=EBfGcTA JF4o&feature=related In the previous example, the salt (NaCl) becomes dissolved in the water, forming a solution. A solution is composed of a substance dissolved in another substance. The substance dissolved is the solute and the substance that dissolves the solute is a solvent. In this example, the solvent is water and the solute is salt. A solution in which water is the solvent is called an aqueous solution. Dissociation of Water • The force between water molecules is so strong that the oxygen of one water molecule can remove a hydrogen atom from another water molecule. The water molecule, therefore, breaks apart. • This is called dissociation of water. • H2O H+ + OH- • The free H+ ion can react with another water molecule. • H+ + H2O H3O+ • H3O+ This is called a hydronium ion pH • The pH scale is a measurement system that indicates the concentration of hydronium ions (H30+) in a solution (compared to hydroxide) ions) (OH- ). • Hydrogen ions are used as the basis of the pH scale because they are an important factor in many chemical reactions. • The letters “pH” stand for potential of Hydrogen. • This term was introduced in 1909 by the Danish chemist, Soren Sorensen. Acids and Bases • If the # of H30+ > # of OH- = acid. • If the # of H30+ < # of OH-, = base (alkaline) • If the # of H30+ = # of OH-, neutral solution. pH and your diet http://www.neok12.c om/php/watch.php?v =zX766f570456540f5 a6d5241&t=Acids- and-Bases REDOX Reactions • are a family of reactions that are concerned with the transfer of electrons between atoms. • Oxidation describes the loss of electrons. • Reduction describes the gain of electrons. • Redox reactions are a matched set -- you don't have an oxidation reaction without a reduction reaction happening at the same time. • For atoms in their elemental form, the oxidation number is 0. • For ions, the oxidation number is equal to their charge. For ex: the oxidation # of oxygen is 2-.. • Because oxygen is unstable (needs 2 more electrons), it is “ACTIVELY” hunting for electrons. Certain foods/drinks/stress- ful lifestyles can release active oxygen into your body. Active oxygen steals electrons from healthy cells forming “free radicals”. Free radicals then steal electrons from other healthy cells. In turn, these cells steal electrons from other cells and so on and so on… • UV rays trigger free radicals, destructive molecules that act like little darts, poking holes in skin's support structure that lead to lines and sagging. Free radicals • Each free radical is capable of destroying an enzyme, protein molecule or a complete cell. These reactive substances can damage cell structures so badly that immunity is impaired and mutate DNA codes. • They can combine and react chemically with other molecules that they were not meant to combine with. This process is called oxidation. • Free radicals also speed up the process of aging, such as the breakdown of collagen. In addition, because they react with oxygen, free radicals may reduce the oxygen supply to your cells. • Every second of our lives billions of free radicals wage war in our bodies. This seriously compromises the immune system which threatens our vitality. Common dietary causes of free radicals • Refined sugar* see next slide • Food additives • Refined flour and other grain products (corn, pasta) • Moldy foods (blue cheese) • Prepared foods (high in both sugar and preservatives) • Foods cured in nitrites (bacon, sausages, salami etc) • Foods high in pesticides (non-organic produce) • Hydrogenated vegetable oils, margarine etc. How can we stop free radicals from damaging our bodies??? You need to increase the amount of anti- oxidants in your diet! More Best Sources of High Antioxidants Fruits Berries (Cherry, blackberry, strawberry, raspberry, crowberry, blueberry, bilberry/wild blueberry, black currant), pomegranate, grape, orange, plum, pineapple, kiwi fruit, grapefruit. Vegetables Kale, chili pepper, red cabbage, peppers, parsley, artichoke, Brussels sprouts, spinach, lemon, ginger, red beets. Dry Fruits high in antioxidants Apricots, prunes, dates. Legumes Broad beans, pinto beans, soybeans. Nuts and seeds Pecans, walnuts, hazelnuts, ground nut, sunflower seeds. Cereals Barley, millet, oats, corn. Spices cloves, cinnamon, oregano The pH scale ranges from 0 to 14. Acidic solutions range from 0 to 6 Basic (Alkaline) solutions range from 8 to 14 Neutral solutions (such as pure water) are 7 on the pH scale. Using the pH scale handout, place the following examples on the scale: BUFFERS •Buffers are chemical substances that neutralize small amounts of acids or bases in a solution. If our body’s pH fluctuates too much, our organs will begin to shut down and we will die. •Bicarbonate is one of the body's major buffers. Tums and other antacids are buffers which neutralize the acid in your stomach. •The active ingredient in aspirin is acetylsalicylic acid. Why would doctors recommend buffered aspirin for some people, especially those who have a “sensitive” stomach? Carbon Bonding • Carbon bonds easily and often with other carbon molecules, forming: • Straight chains: Rings: C-C-C-C-C • Branched chains: C C-C-C-C If something has carbon in it, it is called organic. Carbon bonding continued.. • Carbon needs 4 more electrons in its valence shell to become stable. (Octet rule) • As mentioned, carbon atoms often bond with other carbon atoms but also with hydrogen atoms too. • Carbon can make single, double or triple bonds. These are in cigarette smoke! Acetylene Benzene : FYI: Acetylene • Its combustion in pure oxygen produces the highest achievable flame temperature, over 3300 °C, allowing it to weld, cut, braze and solder metals in various environments: from great depths underwater to the extreme cold of Alaska. The oxy- acetylene torch is used to repair ships underwater, to construct bridges, pipelines, dams, tunnels, buildings and to reinforce concrete. • When the following chemicals are added to acetylene, this is what can be made: • Hydrogen chloride ; pipe, siding, rain gutters, molded bottles, electrical insulation, floor and wall coverings, upholstery, garden hoses and waterproof clothing. • Hydrogen cyanide: rubbers, acrylic fibers, and insecticides. • Acetic acid : films and lacquers. • Alcohol : vinyl ether used as an anaesthetic. • Water : used as a solvent and flavoring in food, cosmetics and perfumes. • Chlorine : used as a solvent for fats, phenol and camphor. • Formaldehyde: makes resins including urethane foams for cushioning material, carpet underlay and bedding, insulation in refrigerated appliances and vehicles, sealants, caulking and adhesives. • Acetylene reacts with carbon monoxide and alcohol forming acrylate esters used in the manufacture of Plexiglass and safety glasses. http://www.youtube.com/watch?v=X1LwYJ8pDhc FYI: Benzene • Some industries use benzene to make other chemicals which are used to make plastics, resins, and nylon and synthetic fibers. • Benzene is also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. • Natural sources of benzene include volcanoes and forest fires. • Benzene is also a natural part of crude oil, gasoline, and cigarette smoke. http://www.youtube.com/watch?v=r6sGMQKFBh4 A partial list of the 599 additives approved by the US Government for use in the manufacture of cigarettes Benzene (petrol additive) A colorless cyclic hydrocarbon obtained from coal and petroleum, used as a solvent in fuel and in chemical manufacture - and contained in cigarette smoke. It is a known carcinogen and is associated with leukemia. Formaldehyde (embalming fluid) A colorless liquid, highly poisonous, used to preserve dead bodies - also found in cigarette smoke. Known to cause cancer, respiratory, skin and gastrointestinal problems. Ammonia (toilet cleaner) Used as a flavoring, frees nicotine from tobacco turning it into a gas, found in dry cleaning fluids. Acetone (nail polish remover) Fragrant volatile liquid ketone, used as a solvent, for example, nail polish remover - found in cigarette smoke. A partial list of the 599 additives approved by the US Government for use in the manufacture of cigarettes Nicotine (insecticide/addictive drug) One of the most addictive substances known to man, a powerful and fast-acting medical and non-medical poison. This is the chemical which causes addiction. Carbon Monoxide (CO) (car exhaust fumes) An odourless, tasteless and poisonous gas, rapidly fatal in large amounts - it's the same gas that comes out of car exhausts and is the main gas in cigarette smoke, formed when the cigarette is lit. Tar Particulate matter drawn into lungs when you inhale on a lighted cigarette. Once inhaled, smoke condenses and about 70 per cent of the tar in the smoke is deposited in the smoker's lungs. Arsenic (rat poison) Hydrogen Cyanide (gas chamber poison) Energy Energy = the ability to work and cause change. (kinetic energy) Energy can be in many different forms. Ex. Thermal (heat), radiant (light), electrical, mechanical, & chemical. Free energy = the energy available to do work. (potential energy) Some animals use kinetic energy to catch and eat other animals. Some animals use kinetic energy to not get eaten by other animals. Sometimes kinetic energy is just fun. It feels good to run, or to be more technical, to convert potential energy stored in our cells into the kinetic energy of our body Energy & Chemical Reactions Chemical reactions that NEED (absorb) energy are called ENDERGONIC. Ex. Photosynthesis Energy & Chemical Reactions Chemical reactions that RELEASE energy are called EXERGONIC REACTIONS ACTIVATION ENERGY In both reactions, energy is needed to “get the ball rolling”. This is called ACTIVATION ENERGY. Some chemicals actually reduce the amount of activation energy needed. These are called CATALYSTS. One group of catalysts are called ENZYMES. Most organic compounds have clusters of atoms called functional groups. The functional group is the structural building block that determines the characteristics of the compound. One very important functional group is the hydroxyl group (-OH). Alcohol is an organic compound with a hydroxyl group attached to one of its carbons (making alcohol polar like water). Assignments Honors: Complete functional group work packet to fully understand the composition of the common function groups.
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