1.Explain the role each component of the atom plays in the characteristics or properties of atoms. Include elements, isotopes, ions, atomic weights, numbers, etc. Give examples of each and explain why you’re example fits.

A chemical element is a sample of matter that cannot be separated into simpler particles by any chemical or physical means except nuclear reactions. Most matter is found in nature as mixtures, which chemists can separate into pure substances (compounds and elements). A chemical compound is a sample of matter that contains two or more elements in the same proportions throughout. Every chemical compound can be described by a chemical formula. Compounds can be broken down chemically into their constituent elements. (Note that the term substance refers only to elements and compounds, that is, to samples of matter in which the proportion of each element is fixed and reproducible. The term element refers to an elemental substance, that is, one that cannot be separated into simpler substances. The term compound refers to a compound substance.)Atomic structure distinguishes one element from another. An atom is composed of a nucleus containing positively charged particles called protons (and particles with no charge, called neutrons), surrounded by negatively charged particles called electrons. The number of electrons equals the number of protons, so that the atom as a whole has no charge. Each element is characterized by the number of protons that an atom of that element contains, called its atomic number. All atoms having the same atomic number have the same chemical properties; for example, all atoms with six protons have the properties of the element called carbon. Besides its name, each element is given a symbol; the symbol for carbon is C. The capacity of an atom to combine with others is determined by the number of electrons it gains or loses or by the number of pairs of electrons it shares. This combining capacity is also called the valence number of the elements. Many atoms react to form molecules by sharing pairs of electrons. A more precise term, covalence, designates the combining capacity of elements by this process. Atoms also act to form ions by gaining or losing electrons. Chemists designate this kind of combining capacity of elements by the term electrovalence. The electrovalence of an ion is the numerical value of the electrical charge on the ion. Many kinds of atoms enter into compounds either by covalence or by electrovalence, depending upon surrounding conditions. Many elements also have several values of covalence and electrovalence. The term isotope defines atoms that have the same number of protons but a different number of neutrons; that is, they are atoms of the same element that have different masses. Their atomic number (proton number) is the same, but their mass numbers (the total number of protons and neutrons in the nucleus) vary. Lighter elements tend to possess fewer isotopes (hydrogen has 3), while heavier elements tend to have more isotopes (polonium has 27). Several ways of denoting isotopes are used where the letter or letters representing the element is proceeded by superscript and/or subscript numbers, the superscript indicates the mass number and the subscript denotes the atomic number. There are two major types of isotopes, stable and unstable. Stable isotopes do not undergo radioactive decay, but rather persist in nature. Unstable isotopes--radioisotopes or radio nuclides--undergo radioactive decay toward a more energetically stable form. Stable isotopes, of which there are approximately 280, make up most of the natural elements of the Earth. The major component of an element is usually one stable isotope accompanied by minor amounts of other stable and unstable isotopes. Sometimes an element, such as chlorine, is composed of more than one stable isotope in quantity; therefore, certain elements may have several atomic masses that differ greatly. Twenty-one elements have only one isotope and therefore consist of only one kind of atom. Radioisotopes are of two major types, natural and artificial. Natural radioisotopes, of which there are only 25, were formed during the creation of the Earth; the only radioisotopes left from that time are those that decay very slowly. New radioisotopes are constantly being created; some are members of a decay series in which unstable isotopes decay to other unstable isotopes until a stable isotope is reached, and some are produced continuously in the Earth's atmosphere by cosmic-ray bombardment. The rate of decay of these types of isotopes has reached an equilibrium with their rate of formation. Tritium is an example of a rapidly decaying isotope, while carbon-14 is an example of a more slowly decaying radioisotope produced in this fashion. Both are formed by the cosmic-ray bombardment of nitrogen-14. The atomic number of an element, which indicates its place in the periodic table of elements, is the number of protons (positively charged elementary particles) in the nucleus of one of its atoms. If an atom is electrically neutral, the same number of electrons are present. Atomic number is often symbolized with the letter Z and is shown as a numerical subscript to the left of its chemical symbol. For example, the letter C preceded by a superscript number 12 and a subscript number 6 indicates a carbon atom of atomic mass 12 and atomic number 6, the difference being equal to the number of neutrons present in the nucleus. Atomic weight is the average mass of atoms of an element relative to some standard; the present standard is the carbon- 12 isotope, which is assigned an atomic weight of exactly 12 atomic mass units (AMU). Mass numbers (the sum of an atom's protons and neutrons) are always whole numbers, but the atomic weight of an element is the average of the weights of its isotopes, taking the frequency of their natural occurrence into account, and is not usually a whole number. A gram atomic weight is a quantity of an element in grams that has the same numerical value as the element's atomic weight; the gram atomic weight of carbon is 12 grams. Such a quantity always contains 6.022 times 10 to the 23rd power atoms (one mole). An atom can be removed from its ground state only when enough energy is given to it, by radiation or collisions, to raise an electron to an "excited" state. For most atoms this excitation energy corresponds to several electron volts. Radiometric age-dating, or radiometric dating, is the determination of the age of materials by means of their radioactive contents. When scientists first began to try to establish the ages of rocks, minerals, and other Earth materials, they had to resort to deductive methods. They observed rock strata in different regions for comparative dating, and through growing knowledge of the physical processes involved they would try to estimate the times needed for formative physical processes to have taken place. With the discovery of radioactivity at the end of the 19th century, however, geologists gained a much more precise tool for the dating of past Earth events. This tool, radiometric age-dating, is based on the fact that every radioactive element decays. That is, the so-called "parent" element emits radiation and particles until it is transformed by the loss into, eventually, a stable "daughter" element, sometimes passing through a series of transformations into other radioactive elements before reaching this stability. Each radioactive element also has its own pattern and rate of decay. Most rocks and minerals contain atoms of one or more radioactive elements. These elements arise from various sources. Some derive from stellar materials even before the solar system was formed, or from materials produced during the early moments of that formation. They have decay rates so slow that some of their atoms have not yet decayed completely. Other radioactive atoms in the Earth are the unstable products of these longer-lived elements. Some radioactive elements are continually being produced, as well, by nuclear reactions caused by the interaction of cosmic rays with molecules in the atmosphere. The decay of radioactive atoms and the resulting formation of their stable daughters is described by the law of radioactivity. Suppose all the daughter atoms that form by decay of a radioactive parent in a mineral are allowed to accumulate in the mineral. A simple mathematical formula that incorporates the decay rate of the parent element then yields the ratio of daughter to parent atoms after a given period of time. Such equations are used for dating minerals by the potassium-argon (K-Ar), rubidium-strontium (Rb-Sr) and uranium (U) or thorium-lead (Th-Pb) methods. Other methods are also described below. In general, the concentrations of the chemical elements of the parent and daughter must be measured, as well as the isotopic composition of the element containing the daughter. The isotopic composition--that is, the relative abundances of all naturally occurring isotopes of an element--is measured by mass spectrometry.

K-Ar Method: Naturally occurring radioactive potassium-40 decays to argon-40. The minerals datable by the K-Ar method, and variations on the method that also make use of this decay sequence, include the micas and hornblende in igneous and metamorphic rocks, certain kinds of feldspar and unaltered glass in volcanic rocks, and the clay mineral glauconite in sedimentary rocks. K-Ar dates have been used to construct the geologic time scale, to map structural provinces in North America and other continents, and to establish a chronology for reversals of the Earth's magnetic field .

Rb-Sr Method: Approximately one-third of all rubidium atoms are radioactive rubidium-87, which decays to stable strontium-87 by emission of a beta particle. The abundance of the strontium isotope relative to radioactive and nonradioactive rubidium isotopes in a rock increases as a function of time according to a well-established mathematical relationship. Most rubidium-bearing minerals, such as the micas, feldspars and glauconite, can be dated in this way. In fact, this procedure has been used to date the oldest known terrestrial rocks, from Greenland, as well as rocks obtained from the Moon. Stony meteorites have also yielded a date, in this way, that is accepted as a reliable estimate of the age of the Earth.

U or Th-Pb Methods: All the isotopes of uranium and thorium are radioactive and decay to stable isotopes of lead by the emission of alpha and beta particles. Because uranium and thorium commonly occur together, their minerals can be dated by three independent methods involving different decay sequences. (The dates obtained by these methods are often in disagreement, but a graphing technique resolves these difficulties.) Most minerals containing uranium and thorium in relatively large amounts are not suitable for dating, either because they lose the daughter lead or because they are too rare to be useful. The minerals zircon, monazite, sphene, and apatite, in which uranium and thorium occur as trace elements, are used instead. The U and Th-Pb methods have been widely used to date the granitic gneisses of Precambrian age that occur on all of the continents.

The Fission-Track Method: When an atom of uranium-238 undergoes spontaneous fission, the fragments leave damage trails in crystals that can be made visible under the microscope by etching. The number of such tracks per unit area on a mineral surface is related to its uranium concentration and its age. The observed density of tracks is used to date uranium-bearing minerals and glasses. This method is sensitive to the temperature history of minerals because of the fading of fission tracks at elevated temperatures.

The Common-Lead Method: The isotopic composition of lead in its principal ore mineral, galena, can be treated as a mixture of primordial lead (inherited by the Earth from the solar nebula) and varying amounts of radioactivity-produced lead depending on the age of the ore deposit. Young deposits contain more radioactivity produced lead than do older ones, because they had less time for the uranium and thorium to decay. The common-lead method can be used to date the deposits, and may reveal the age of the granitic basement rocks that form the continental crust.

The Ionium-Thorium Method: Ionium (thorium-230) is a radioactive daughter of uranium-238. It enters the oceans by the discharge of rivers or by decay of uranium-234, its immediate parent. All of the isotopes of thorium in the oceans are rapidly removed to the sediment, whereas uranium tends to remain in solution. This process separates ionium from its parent, and its radioactivity in the sediment therefore decreases with time as it decays to radium-236. The radioactivity contributed by the common thorium isotope, thorium-232, however, remains practically constant because of its slow rate of decay. A simple mathematical treatment of the ratio observed between ionium and thorium-232 provides a method of dating sediment recovered from the ocean bottom and determining the rate of sediment accumulation. The method is suitable for dating sediment deposits during the past 150,000 years, which includes the most recent ice age. Other radioactive daughters of uranium-238 may also be used.

Carbon-14 Method: Carbon-14 is a relatively short-lived radioisotope of carbon that is produced in the upper levels of the atmosphere by the interaction of energetic neutrons, produced by cosmic rays, with the nuclei of stable nitrogen-14. The carbon-14 atoms are rapidly incorporated into molecules of carbon dioxide, which is taken up by green plants in the course of photosynthesis. As long as the plants, or animals that feed on them, are alive, the level of radioactivity from carbon-14 in their tissues is constant, because the loss by decay is compensated by addition of carbon-14 from the atmosphere. When the organism dies, however, the radioactivity decreases with time at a well-established rate. Dating by this method, which was developed by Willard LIBBY, is applicable primarily to materials such as wood, seeds, and bones. It has been used by archaeologists, anthropologists, and geologists to date samples as old as 35,000 years, although 10,000 years has been the more practical limit. Using accelerator-augmented techniques, scientists hope to push this limit back toward 100,000 years.

Tritium Method: Tritium is a naturally occurring radioisotope of hydrogen that is produced in the upper atmosphere by nuclear reactions involving cosmic rays. The natural tritium content of water on the Earth's surface is very low, but significant increases have occurred as a result of the testing of nuclear weapons in the atmosphere. The episodic input of tritium from the atmosphere into the oceans and groundwater has been used to measure the rate of movement of water masses.

Adenosine Triphosphate(ATP) holds energy for living organisms is an example of this. ATP may even be converted into light energy in some organisms.. The ATP molecule comprises a nitrogen compound, adenine, linked to a molecule of sugar, ribose, to form adenosine. On the adenosine molecule is a chain of three phosphate groups that can be removed one by one to produce ADP (adenosine diphosphate, having two phosphate groups), and AMP (adenosine monophosphate, having only one phosphate). As each phosphate group is removed, the bond that connects it to the rest of the molecule breaks, releasing energy for the cells to use in their various activities. Photosynthesis is another example of potential energy. Photosynthesis is the biological process by which the energy of sunlight is absorbed and used to power the formation of organic compounds from carbon dioxide and water. The photosynthetic process can be divided into two stages: absorption of light energy, known as the light reactions, and carbon fixation, known as the dark reactions.

The Light Reactions-In this stage colored pigments called chlorophyll’s absorb, or trap, light energy from the Sun. This causes the flow of a tiny electrical current, which converts the energy into two high-energy chemicals, adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH).

The Dark Reactions- Carbon fixation uses the energy contained in ATP and NADPH to drive reactions that form organic compounds, such as starch and sugars, from the simple molecules of carbon dioxide and water. The organic compounds formed can subsequently be broken down during respiration to release energy and sustain life.

An important outcome of the photosynthetic reaction is that the light-induced electrical current causes the water to break down. Water is the source of electrons for the electrical current and one of its component atoms, oxygen, is released as molecular oxygen due to this decomposition. This replenishes the atmospheric oxygen supply, which would otherwise be depleted by respiratory processes of organisms or by burning substances, and also depletes the carbon dioxide that it produces. The reactions are summarized as follows:

Respiration: organic compounds + oxygen ---> carbon dioxide + water

Photosynthesis: carbon dioxide + water ---> organic compounds + oxygen

Thus, the process of photosynthesis is the opposite of respiration. All plants contain the chemical which is essential for photosynthesis, which is named chlorophyll. Chlorophyll is found in chloroplasts, which are in small granules in plant cells. Although nearly every part of a plant contains chlorophyll, the leaves are specialized for photosynthesis and are especially rich in the pigment. Chloroplasts also contain yellow, orange, and occasionally red pigments, called carotenoids, which may mask the green chlorophyll and give the characteristic yellow or orange color to many flowers, ripe fruit, and autumn leaves. Several types of chlorophyll occur in organisms capable of photosynthesis. The most common type is chlorophyll a, which is distributed throughout nearly all green plants. Chlorophyll b is the second most widely distributed; it is found in all higher plants and some algae. The photosynthetic bacteria contain still other chlorophyll’s. Chlorophyll traps the energy of sunlight. When it absorbs a single photon, the smallest energy unit of light, the energy is transferred to one of the highly mobile electrons of the chlorophyll molecule and raises the electron to a higher energy state. The additional energy is used to break down water in the plant into oxygen and hydrogen. Oxygen is released, but hydrogen is used to convert atmospheric carbon dioxide into plant sugars and starches. In electrical lights, the atom’s electron are moved to a higher state by the bombardment of electrons from the electricity.. When the atom is excited, it will usually emit electromagnetic radiation rapidly and return to the ground state. The radiation is emitted in the form of individual packets or quanta, of light, called photons. Each photon has an energy equal to the difference between the energy of the excited states and the ground state of the atom.

2.Explain in detail HOW the following bonds are possible using the information used in #1. You must use an example and explain how the example fits the atomic theory

1. Ionic Bond
2. Covalent Bond
3. Hydrogen Bond
4. Metallic Bond
5. Sulfide Bond

A. Polar molecules are readily soluble in water. They are formed when atoms exchange an electron to form a bond called an ionic bond. These bonds are strong because the atoms have become more stable as a result of either losing or gaining an electron (called ionization). Molecules formed from ionic bonds are not true molecules because the electrons are not shared but exchanged. Compounds formed by ionic bonding are made up of a random mixture of ions atoms or groups of atoms that carry an electric charge as a result of having lost or gained electrons. They retain a charge because they are not bonded to the particular atom with which they exchanged electrons. An example is sodium chloride (NaCl), or common table salt. Sodium gives up an electron and becomes positively charged (Na+) when heated in the presence of chlorine. This electron is acquired by chlorine, leaving it with a net negative charge (Cl-). The resultant water-soluble NaCl is a collection of free ions that are capable of conducting an electrical current.

B. A covalent bond forms when two atoms attract the same pair of electrons, which is said to be shared. A covalent bond affects only two atoms, but most atoms can form more than one covalent bond at a time. Atoms of oxygen or sulfur, however, form two covalent bonds in many of their compounds. Atoms of nitrogen or phosphorus form three or five. Two atoms can share two or three pairs of electrons, forming double or triple covalent bonds. In homonuclear covalent bonds (bonds between identical atoms in a molecule), the electrons are equally shared by the two nuclei. In these molecules the bonds are termed non polar covalent. When the two atoms joined are not identical, however, the pair of electrons is generally not shared equally by the two nuclei, and the bond is termed polar covalent. In a polar-covalent bond, the pair of electrons will spend more time near the nucleus of the atom having the greater electron-attracting power. The ability of an atom to attract electrons and thus polarize a bond is called its electronegativity. The most electronegative elements are fluorine oxygen, nitrogen, and chlorine. Most chemical bonds are polar covalent. In hydrogen fluoride, HF, the bond is polarized as electrons are drawn toward the fluorine nucleus. The compound hydrogen fluoride consists of molecules in which one atom of hydrogen and one atom of fluorine are held together by a covalent bond The HF molecule has a permanent DIPOLE moment, the negative end of which is at the fluorine atoms. Ammonia has three polar-covalent bonds, directed along the edges of a pyramid with the nitrogen atom at the apex.

C. Hydrogen bond is a weak, electrostatic, attractive interaction between a hydrogen atom bonded to an atom in one molecule and an electronegative atom of another or even the same molecule. Electronegative atoms are those that pull electrons toward their nuclei in a polar covalent bond. The four most electronegative elements are fluorine, oxygen, nitrogen, and chlorine. Hydrogen-bonding interactions between molecules are responsible for some very unusual and important properties of matter. In liquid water, for example, hydrogen atoms bonded covalently to the oxygen atom of one molecule are hydrogen bonded to the oxygen atoms of adjacent water molecules. These interactions must be disrupted to boil water and therefore cause its boiling point to be much higher (100 deg C/212 deg F) than it would be if there were no hydrogen bonding. Hydrogen bonds can also occur within molecules. Intramolecular hydrogen bonding between the hydrogen atoms of N--H bonds and oxygen atoms helps fold proteins into specific three-dimensional shapes that are essential for their biological activity. An example of a hydrogen bond would be water (H₂O).

Water is a polar molecule where two hydrogen’s bond to one oxygen. The hydrogen’s are negative, and the oxygen is positive. Oxygen originally has 6 electrons, and each hydrogen has 1 electron. The atoms combine, sharing the electrons (8 electrons). Most of the time, the electrons spend there time around the oxygen.

D. A kind of bonding that often occurs between metal atoms in a lattice is called metallic bonding. The metallic bond is similar to the covalent bond except that many (often six to twelve) atoms surround a central metal atom in a solid lattice. Generally there are not enough electrons for there to be a full complement of two electron bonds between each pair of atoms. As a consequence, the electrons are spread out over a wide area, often encompassing the entire solid lattice. With not enough electrons to populate all the bonding molecular orbitals, a much wider range of electron delocalization results. These electrons constitute the conduction band and account for many of the familiar properties of metals, such as their ability to conduct heat and electricity, their malleability, their ductile character, and their high light reflectivity. An example of a metallic bond is iron. Every atom in iron is connected by a metallic bond. The electrons in it are delocalized in this lattice. Because of this, a sea of electrons can pass through this, therefore it is a good conductor of electricity

F. In a sulfide bond, sulfur bonds with sulfur making S₈. A Disulfide bond helps proteins into their proper shape. This example fits the theory since it is a ring of 8 sulfurs connected together

3. Explain the different kinds of energies found in atoms. Give real examples of how they are used by humans in technology. How do these examples work? (Hint: atomic and hydrogen bombs, electricity, explosives, fire, radiation, chemical hot and cold packs.)

Strong force in the nucleus of an atom-The strong force in the nucleus is used in the atomic bomb. When you pull apart the strong force or put it together meaning pulling apart the nucleus of an atom or putting it together, you get a big explosion, Kaboom!! An example of this would be the hydrogen or the atomic bomb. In the atomic bomb the strong force is pulled apart. Fusion bombs have a higher yield than fission bombs.

Electromagnetic energy- The electromagnetic force is a unified force of electricity and magnetism. The electromagnetic energy holds electrons against nucleus and makes hydrogen bombs work. It also makes ionic bonds and ions work. An example would be the electricity flowing through the power lines providing power too houses. This examples work because the electrons flow through the wires at an excited state and release energy.

Kinetic energy- Atoms are constantly in motion. Kinetic energy is the measure dependent on how fast the atoms move. If they move really fast, you have got a gas. If they move really slow, then you have a solid and in between the two at some point dependent on the element, they will be a liquid. An example of this would be boiling water. The water has a higher temperature and the atoms move faster and it boils and some of it turns to steam.

Potential energy- This is if you boost electrons into a higher orbital and make them more excited. An example of potential energy would be

Chemical energy- A chemical reaction is the process of breaking chemical bonds or forming new bonds or both. In a chemical reaction the atoms of the reactants combine to form the products of the reaction. For example, the reactants Na⁺ and Cl^- combine in a chemical reaction to form the product NaCl. Chemical equations show the reactants change during chemical reactions. The reactants are shown on the left side of the equation; the products of the reaction are shown on the right side. The number of each kind of atom must be the same on either side of the arrow. Some reactants and products are shown below:

Reactants Products

For most chemical reactions to occur, energy must be added to the reactants. The activation energy is the amount of energy required for the reaction to begin. Touching a burning match to a piece of paper supplies the activation energy necessary for the molecules in the to react with oxygen – that is, to burn. Once started, every chemical reaction involves either a net release of energy or a net absorption of energy. A chemical reaction that liberates heat is exothermic, and a reaction that absorbs heat is endothermic. Alternatively, if the total energy of the reaction products is less than the total heat of the reactants, the reaction must then be exothermic; if the reverse is true, the reaction is endothermic. These energy changes in reactions are generally determined by directly measuring the heat released or absorbed in the reaction. The changes can also be calculated by using hess's law, in which heats of partial reactions or reaction steps are summed.The change in the heat content of the substances after a chemical reaction occurs is called the heat of reaction; it is usually represented by the symbol delta H. By convention, a negative delta H indicates an exothermic reaction, and a positive delta H shows that the reaction is endothermic. The symbol delta H is measured when the final state of the system is brought to 25 deg C (77 deg F), the same as its starting temperature. Pressure is assumed to be one atmosphere, and each substance is assumed to be in its usual state under these conditions. For example, the burning of graphite (carbon) to form carbon dioxide is an exothermic reaction. The heat of reaction, in this case -94.05 kcal, applies to one mole of substance. This amount of heat represents the molar heat of formation of carbon dioxide, as well as the heat of combustion of graphite.Examples of exothermic reactions are the burning of fuels, the dissolving of concentrated sulfuric acid in water, the combination of hydrogen and oxygen to form water, and the combination of nitrogen and hydrogen to form ammonia. Examples of endothermic reactions are the combination of nitrogen and oxygen to form nitrogen oxide, the dissolving of ammonium chloride in water, the dissolving of salt in water, the combination of hydrogen and iodine to form hydrogen iodide, and the conversion of liquid bromine to gaseous bromine.

electrical energy- One of the most important kinds of energy in the modern technological world is electrical energy. Electric currents turn motors and drive machinery. Electric currents provide the energy of laborsaving applicances such as electric mixers, power drills, vacuum cleaners, and automatic dishwashers. Clearly, the currents possess energy. Electrical energy is linked with the basic structure of the atom. According to modern atomic theory an atom has a heavy, positively charged center called the nucleus. One or more light, negatively charged electrons circulate around the nucleus. The positive nucleus and the negative electrons attract one another. This attraction keeps most of the electrons circulating near the nucleus. But sometimes a neighboring nucleus will also attract the electrons of the first atom. This is how a chemical bond is formed. So, in a way, all chemical energy is a special, microscopic kind of electrical energy. Metals are made up of atoms that contain many electrons. Because of the peculiar structure of metal atoms, the atomic nuclei are not strong enough to hold on to all their electrons. Some of the electrons more or less float from nucleus to nucleus. These free electrons can take part in an electric current. Work must be done to separate positive and negative charges if one is to produce a surplus of electrons in one place and nuclei that are missing one or more electrons at another place. When this situation occurs, as in a battery, energy is stored. If one end of a metal wire is connected to the place where excess electrons are collected (the negative terminal on a battery) and the other end of the wire is connected to the place where excess nuclei are collected (the positive terminal on a battery), the electrons of the wire flow to join the nuclei. Electrons farther down the wire flow after the first electrons, and the electrons from the battery move into the wire. This total electron flow from the negative terminal of the battery through the wire and into the positive terminal is called an electric current. Since a force is applied that makes the electrons move a certain distance down the wire, work is done.

4. Explain on atomic level why water has the charasteristics necessary to support life. (Hint: water’s polarity)

A water molecule is an hydrogen bond.. An hydrogen bond is where two water molecules share partially their electrons.

Water molecules have a hydrogen bond. A water molecule has an oxygen and two hydrogen’s Oxygen attracts the hydrogen's electrons forming a covalent bond, but because oxygen has more protons it practically takes hydrogen's electrons away. One side of H₂O is negatively charged and one side is positively charged, this is caused by that that the electrons taken from the hydrogen's make that side positive which makes the compound uneven. And since two compounds have these properties, this is why a hydrogen bond occurs. It occurs when two H₂O compounds join because one of their sides is positive and one negative. Because water is a polar compound, it is an effective solvent. For example, when ionic compounds interact with water, the compounds often break apart, or dissociate into ions. This splitting or breaking up of an ionic compound frees ions to participate in biological reactions. Because of water’s polarity, it supports life.

5. Describe with real examples all the characteristics of water which makes life possible.

Water is liquid at room temperature. Because of this it also supports life. Capillarity is the rise or fall of a liquid between solid walls due to the equilibration of surface tension forces and the weight of the raised fluid. The forces acting on a fluid particle at the top of the meniscus (surface) are the surface tension between the atmosphere and the wall, the surface tension between the liquid and the atmosphere, and the surface tension between the liquid and the wall. When the liquid wets the solid, there is also a force of adhesion between the liquid and solid that is greater than the cohesion of the liquid. Thus, the liquid between the walls rises or falls to a height required to balance all forces; for non wetting liquids such as mercury, the meniscus is depressed. The height to which a liquid is raised in a capillary tube is inversely proportional to the radius of the tube. Capillarity is responsible for the rapid wetting and retention of liquids by absorbent paper and fabrics.

Cohesion is the tendency of matter to hold itself together, a result of intermolecular attractive forces. As two molecules or atoms of a body approach each other, their potential energy reaches a minimum value at a certain equilibrium distance. Work is then required, either to push them closer together or to pull them farther apart. Any force tending to decrease the distance meets with a rapidly increasing reaction of compressive elasticity, whereas any force tending to increase this distance is opposed by cohesion. Cohesion is great in solids, much less in liquids, and practically nonexistent in gases. The cohesive property of some materials is diluted by the adhesive properties of its parts; thus their ultimate strength may not be a true measure of cohesion. In physics, adhesion is the attraction of two different substances, one of which is usually a liquid and the other a solid. Adhesion results from intermolecular forces between the substances and is distinct from cohesion, which involves only intermolecular attractive forces within a single substance. The forces in both adhesion and cohesion are chiefly Van Der Waals forces. The competition of adhesive and cohesive forces results in capillarity, in which a liquid either rises or falls in a fine tube.

Common units of heat are defined in terms of the specific heat of water at a standard temperature. One calorie is the amount of heat energy required to raise the temperature of a gram of water by one Celsius degree. Similarly, a British thermal unit (Btu) is the amount of heat required to raise a pound of water by one Fahrenheit degree. The specific heats of most materials remain essentially constant over the common range of temperatures. At extremely low temperatures, however, specific heats become considerably smaller. A volume of gas will accept more heat energy per degree of temperature rise if it is allowed to expand freely than if it is confined. Thus a gas has two distinct values of specific heat: one value at constant pressure, and another, smaller value at constant volume. The ratio of these values is different for different gases and is of importance in describing the behavior of a gas undergoing a thermodynamic process.

Horizontal and vertical density currents occur because most lake water has its greatest density at a temperature close to 4 deg C (39 deg F). Lakes stratify into layers, with less dense water on top (the epilimnion) and denser water below (the hypolimnion). Seasonal warming and cooling of the upper layer increases its density and causes an overturning of the waters. Some lakes turn over once a year (monomictic) and some twice (dimictic). Most lakes circulate at least once a year (holomictic), but in lakes with a strong salinity gradient (with heavy salty water at the bottom) the heating and cooling of the upper layer is not strong enough to produce overturning (meromictic).

Water's physical properties make it vastly different from most other liquids. Water, for example, has the rare property of being lighter as a solid than as a liquid. If ice (solid water) were heavier than water, frozen water in a lake would sink to the bottom and pile up to the top, killing all the marine life. Water's ability to store great amounts of heat helps living things survive through wide changes in temperature. The amount of heat produced by a man during one day's activity would be enough to raise his body temperature by as much as 300 F were it not for the water in his tissues.

When a solvent, such as water, dissolves a solute, such as table sugar, a solution is formed. Many compounds dissolve in water because of water’s polar nature. When covalent compounds dissolve in water, molecules are evenly dispersed in the solution. When ionic compounds are dissolved in water, ions are evenly dispersed in the solution. Elements in the body are present as compounds or dissolved ions in various fluids. When non polar molecules (which do not form hydrogen bonds) are placed in water, th water molecules crowd the non polar together. That is why oil and water do not mix. Nonpolar molecules, which are repelled by water, play many important roles in living things. They are responsible for fine-tuning the shapes of proteins and for maintaining the structure of cell membranes that surround every cell.

Any compound that forms hydrogen ions when dissolved in water is called an acid. When an acid is added to water, the hydrogen ion concentration is increased. A convenient way of relating the amount of hydrogen ion from one solution to another is the pH scale. The pH of most solutions falls within a numerical range from zero to fourteen. The pH of any solution can be determined using a pH meter or indicator papers.

Any substance that ionizes to form hydroxide ions when dissolved in water is called a base. Bases lower the hydrogen ion concentration of water because hydroxide ions react with hydrogen ions to form water molecules.

Bases have hydrogen ion concentrations that are lower than that of pure water. Bases thus have pH values above 7. Household ammonia has a pH of 11, and intestinal fluid has a pH of about 8. Your body’s fluids are constantly monitored in a series of complex processes to keep the pH of these fluids within acceptable levels.

6. Suppose water was not polar. Explain the effects this would have on the earth.

If water was not polar, it wouldn’t be a liquid at room temperature but it would be a gas. The water wouldn’t be attached by hydrogen bonds. There would be no cohesion, or adhesion if water was not polar. Your membranes would dissolve and your fats would also melt. There would be no capillaroty because it wouldn’t work and plant life wouldn’t exist. Also in the plants the membranes would dissolve just like in benzene.

Specific heat is because of a hydrogen bond and permanent dipole movement. The water would be a gas because it would have no hydrogen bonds. The specific heat would be low and there will be efficient evaporation. In polar water, it is hard to change to temperature, it takes time. An example of this would be water set out to boil or water put to cool into ice. If water was not polar, then it could undergo a temperature change really fast and it would not resist change(the temperature will not be buffered).

Water would be a gas at 4 Celsius so no seasonal flushing would occur. Water be most dense somewhere around 0 Kelvin when it would be water at all, seasonal flushing wouldn’t occur unless earth was without a sun to warm it if water was not polar.

The solid form in non-polar water would be heavier. All the ice in the oceans would sink to the bottom creating mass floods and flooding all the land. Ice would not isolate water and soon enough the oceans would be just ice.

Water would not be an effective solvent. There would be no erosion . The life on this whole planet would be changed. Because of water’s polarity, it dissolves things. If water was not polar, it wouldn’t support life. Water wouldn’t mix with other polar compounds. Instead, it would dissolve non-polar compounds like lipids and membranes which are made out of lipids. Water would not be an effective solvent.

There would be no ionization of water. There would be no acids and bases. Salt would not dissolve into the oceans

7. Why is water wet?

Water molecules readily form hydrogen bonds with one another, so water clings to itself in an attraction called cohesion. It is because that water is a liquid and not a gas at room temperature. Hydrogen bonds link many individual water molecules together at the water’s surface, like a crowd of people linked by holding hands. Surface tension forms across the surface of water because of the cohesive attraction between individual water molecules.

The attraction of water to a substance other than water is called adhesion. Water ahhesive to any substance that it can form hydrogen bonds with. That is why some things get "wet" and others, such as waxy substances, that are composed of nonpolar molecules, do not. The adhesion of water to substances with surface charges causes capillary action. Capillary action and cohesion are responsible for the upward movement of water as of a liquid movement up a stem through capillary action.