Examples of Polar and Nonpolar Molecules

The two main classes of molecules are polar molecules and nonpolar molecules. Some molecules are clearly polar or nonpolar, while many have some polarity and fall somewhere in between. Heres a look at what polar and nonpolar mean, how to predict whether a molecule will be one or the other, and examples of representative compounds. Key Takeaways: Polar and Nonpolar In chemistry, polarity refers to the distribution of electric charge around atoms, chemical groups, or molecules.Polar molecules occur when there is an electronegativity difference between the bonded atoms.Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out. Polar Molecules Polar molecules occur when two atoms do not share electrons equally in a covalent bond. A dipole forms, with part of the molecule carrying a slight positive charge and the other part carrying a slight negative charge. This happens when there is a difference between the electronegativity of each atom. An extreme difference forms an ionic bond, while a lesser difference forms a polar covalent bond. Fortunately, you can look up electronegativity on a table to predict whether or not atoms are likely to form polar covalent bonds. If the electronegativity difference between the two atoms is between 0.5 and 2.0, the atoms form a polar covalent bond. If the electronegativity difference between the atoms is greater than 2.0, the bond is ionic. Ionic compounds are extremely polar molecules. Examples of polar molecules include: Water - H2OAmmonia - NH3Sulfur dioxide - SO2Hydrogen sulfide - H2SEthanol - C2H6O Note ionic compounds, such as sodium chloride (NaCl), are polar. However, most of the time when people talk about polar molecules they mean polar covalent molecules and not all types of compounds with polarity! Nonpolar Molecules When molecules share electrons equally in a covalent bond there is no net electrical charge across the molecule. In a nonpolar covalent bond, the electrons are evenly distributed. You can predict nonpolar molecules will form when atoms have the same or similar electronegativity. In general, if the electronegativity difference between two atoms is less than 0.5, the bond is considered nonpolar, even though the only truly nonpolar molecules are those formed with identical atoms. Nonpolar molecules also form when atoms sharing a polar bond arrange such that the electric charges cancel each other out. Examples of nonpolar molecules include: Any of the noble gasses: He, Ne, Ar, Kr, Xe (These are atoms, not technically molecules.)Any of the homonuclear diatomic elements: H2, N2, O2, Cl2 (These are truly nonpolar molecules.)Carbon dioxide - CO2Benzene - C6H6Carbon tetrachloride - CCl4Methane - CH4Ethylene - C2H4Hydrocarbon liquids, such as gasoline and tolueneMost organic molecules Polarity and Mixing Solutions If you know the polarity of molecules, you can predict whether or not they will mix together to form chemical solutions. The general rule is that like dissolves like, which means polar molecules will dissolve into other polar liquids and nonpolar molecules will dissolve into nonpolar liquids. This is why oil and water dont mix: oil is nonpolar while water is polar. Its helpful to know which compounds are intermediate between polar and nonpolar because you can use them as an intermediate to dissolve a chemical into one it wouldnt mix with otherwise. For example, if you want to mix an ionic compound or polar compound in an organic solvent, you may be able to dissolve it in ethanol (polar, but not by a lot). Then, you can dissolve the ethanol solution into an organic solvent, such as xylene. Sources Ingold, C. K.; Ingold, E. H. (1926). The Nature of the Alternating Effect in Carbon Chains. Part V. A Discussion of Aromatic Substitution with Special Reference to Respective Roles of Polar and Nonpolar Dissociation; and a Further Study of the Relative Directive Efficiencies of Oxygen and Nitrogen. J. Chem. Soc.: 1310–1328. doi:10.1039/jr9262901310Pauling, L. (1960). The Nature of the Chemical Bond (3rd ed.). Oxford University Press. pp. 98–100. ISBN 0801403332.Ziaei-Moayyed, Maryam; Goodman, Edward; Williams, Peter (November 1,2000). Electrical Deflection of Polar Liquid Streams: A Misunderstood Demonstration. Journal of Chemical Education. 77 (11): 1520. doi:10.1021/ed077p1520

Preventing, Treating and Controlling Childhood Obesity - Free Essay Example

Sample details Pages: 2 Words: 585 Downloads: 10 Date added: 2019/03/15 Category Health Essay Level High school Tags: Childhood Obesity Essay Obesity Essay Did you like this example? Preventing, Treating and Controlling Childhood Obesity Through research professionals have outlined the risks and factors that develop early childhood obesity in addition to strategies of treatment and prevention offered to individuals diagnosed with obesity. Obesity is defined as a condition of becoming overweight, a condition which in turn affects the wellbeing of the individual who suffers from this ailment. Therefore, medical professionals offer obese patients methods and alternatives to strategically prevent, treat and control obesity. Knowing and identifying the warning signs that may lead to childhood obesity could possible assist individuals to prevent the devolvement of obesity. According to Adolphe Quetelets body mass index formula, professionals can determine if an individuals body weight falls within the overweight category. Through this calculation, the progression of early childhood obesity is easily identified at an early age, hence preventing obesity from expanding into the childs adulthood if not addressed accordingly. Don’t waste time! Our writers will create an original "Preventing, Treating and Controlling Childhood Obesity" essay for you Create order Parents can seek the necessary sources available through educational courses that offer nutritional value that assist in helping children from spiraling into the early stages of corpulence. According to professionals, there are additional implementations that parents may consider that could help a child form obtaining this chronic disease. For the most part, they could create a stress-free, positive and encouraging environment for their children. This will in turn build confidence which may diminish the possibilities of developing depression and insecurities that may lead to future eating disorder tendencies. By seeking professional help, individuals can receive a diagnosis defining the severity of their condition along with a specifically designed plan of treatment. Professionals customize this plan by generating a nutrition, fitness and in some cases an anti-obesity medication plan. Certified dietitians generate a balanced diet that are based on the composition of an individuals physique. In conjunction with the formation of a set nutrition plan a basic fitness plan is drawn out to assist the patient to commence a change in developing a healthier lifestyle. Additional options offered to obese patients is treatment through anti-obesity drugs such as nanomedicine. According to physicians this treatment offers a great amount of therapeutic effectiveness. Once obesity has been intensely examined and treated, an individual may take the necessary precautions in maintaining a designated weight control method. In this stage individuals may use strategies that create a life-long plan that characterizes their desired lifestyle. Of course, individuals may keep in mind to revolve their choices around healthy preferences that generate health-giving results, as outlined by a medical professionals stand point. Through continual, physical activity, balanced nutrition and positive reinforcement an individual may gain the control needed to maintain a healthy weight composure. Therefore, medical professionals state that this contributes to and motives an individual to make healthier choices that deviate from relapsing into making the same decisions that led them to the initial weight gain. After reviewing the risks and factors that lead to possible childhood obesity, individuals may apply the different strategies offered as outlined by professionals and distinguish the prime solutions that will assist in overcoming obesity through treatment, prevention and tactics of sustainability. Through research individuals that are diagnosed with obesity are given a wide range of solutions to aid in the battle of fighting against this chronic disease. This will in turn provide individuals sources where professionals pinpoint the variety of complications associated with obesity, solutions and tactics to assist them to overcome the urge of over indulging in the consumption of improper nourishment along with a high degree of knowledge available through reading material, websites and nutritional classes.

Colon Cancer Treatment and Prevention Free Essays

As representatives of the citizens of New York State, we have a responsibility to ensure that everyone has access to the highest quality health care possible. As a State Senator. I have worked aggressively to fight for increased funding for cancer education and prevention, and to improve and expand health care coverage and treatment, including legislation we are working hard to approve — the Women†s Health and Wellness Act — which would expand treatment and prevention services and insurance coverage for breast cancer and other illnesses facing women in particular. We will write a custom essay sample on Colon Cancer Treatment and Prevention or any similar topic only for you Order Now Colon cancer is currently the second leading cause of cancer deaths, followed only by lung cancer. This year, 130,200 Americans will be diagnosed with colon cancer. Nearly half, 56,300, will die from it. Focusing on expanding treatment and coverage for colon cancer is of critical importance in our continued efforts to provide greater access to preventative health care for all citizens. Because early detection is the key in fighting colon cancer and many other illnesses, it is critically important that we continue to educate people on how they can help to prevent colon cancer – by getting a colon cancer screenings like colonoscopies. Many people are apprehensive about the test itself, which is why we must continue to advocate for quality education and prevention services. One tremendous resource we have here in our region, right here in Rochester, is the University of Rochester†s Institute of Biomedical Sciences where scientists work diligently everyday to help find more effective ways to fight cancer. As the senior member of the Rochester State Legislative Delegation, I worked with my colleagues and Governor Pataki to secure $7 million in State assistance for the Institute and will continue to fight to support these important and life-saving endeavors. Certainly I support providing our health care consumers with greater access to prevention services and more expansive insurance coverage for colon cancer treatments and would encourage everyone interested in this issue to contact their State representatives to share their views and concerns. How to cite Colon Cancer Treatment and Prevention, Papers