Covalent Bonding and Molecular Geometry
Objective
The objective of this exercise is to help in understanding the geometric relationships of atoms in simple molecules and the relationship of hybridization to the geometry present.
Discussion
In the last 30 years, data obtained from spectrometric measurements, Xray and electron diffraction studies, and other experiments have yielded precise information about bond distances, angles, and energies. In many cases, the data confirmed conclusions reached earlier. In other cases, valuable new insights were acquired. Structure theory has advanced far beyond the simple electron dot representations and now rests securely on the foundations of quantum and wave mechanics. Although problems involving only simple molecules can now be solved with mathematical rigor, approximations such as the valence bond theory and the molecular orbital theory are very successful in giving results that agree with experimental measurements.
This exercise will use valence bond theory or hybridization to look at the geometry formed from various hybridizations. You will use a framework model kit which gives the correct angles for the each of these hybridizations.
The first bond formed between any two atoms is always a sigma (s)bond (one that is symmetric about the bond axis). Additional bonds between the same two atoms will be pi (p)bonds (perpendicular to the bond axis). It is the sigmabonds and any lonepairs of electrons occupying the sigma hybrid orbitals that determine the geometry of a molecule. Pibonds are always perpendicular to the sigmabonds and follow the geometry formed by the sigmabonding.
Procedure
Check out a molecular model kit from the stockroom. Read the kit directions to see which framework center is used for each hybridization.
Tetrahedral (sp3 hybridization)
CH4
Construct a model of methane using a tetrahedral center (4 prongs) and four rods of the same color to show how the 4 H's are attached.
Geometry Lewis dot diagram # of s bonds on C Approximate H-C-H angel Max # atoms (incl. C) in one plane Is there a mirror plane(divides the molecule in equal halves) ?
H3CCH3
Construct a model of ethane using a tetrahedral center for each C and the same color rods for all 6 H's with a CC bond present.
Geometry Lewis dot diagram # of s bonds on each C Approximate H-C-H angle Approximate H-C-H angle
The C-C bond is a single bond and has free rotation about it. Arrange the ethane molecule so that each CH bond on one C atom is exactly parallel to a CH bond on the second C atom. (This is the eclipsed position.) View this arrangement by looking along the CC bond such that the atoms on the front C blank out those on the back C.
"Learning to Be Gendered" is an article written by authors Penelope Eckert and Sally McConnell-Ginet, where they examine the reasons behind why children are assigned gender roles in society. In the text, they explore how behavior and language are used to identify a child's gender and the unnecessary stereotypes and sexism perpetuated by this. The authors also address the pressures and expectations that are placed on children to fulfill various gender roles. They attack the theory that children fall into their gender roles due to behaviors and biological reasons. Their article outlines the difficulty to escape the gender stereotypes that have overtaken society and also demonstrate a clear presentation of problems and solutions to this issue. I also think that the article bases its arguments on
There are four different types of hydrocarbons each having a different homologous series (formula for carbon chain). These being an alkane (formula = CnH2n+2), alkene (formula = CnH2n), alkyne (formula = CnH2n-2), and an alkanol which has the same formulae as an alkane only that is has a hydroxide molecule which replaces one of the hydrogen atoms (refer to figure 3 and
Fig 1: Applications of single molecule spectroscopy in solving scientific problems in Physics, Chemistry and Biology
Erikson’s first stage Basic Trust v. Mistrust, similar to Freud’s oral stage, involves learning to trust other people by means of learning that emotion via maternal nurturing. According to Erickson, children with attentive mothers become secure in the fact that mother will meet all their needs and in turn individuals...
The interior angles of the pentagonal portion of theobromine are 108 except for the nitrogen, with a signal bond to a carbon and a double bond to another carbon, which has an angle of 104.5 because it is
The IR spectrum that was obtained of the white crystals showed several functional groups present in the molecule. The spectrum shows weak sharp peak at 2865 to 2964 cm-1, which is often associated with C-H, sp3 hybridised, stretching in the molecule, peaks in this region often represent a methyl group or CH2 groups. There are also peaks at 1369 cm-1, which is associated with CH3 stretching. There is also C=O stretching at 1767 cm-1, which is a strong peak due to the large dipole created via the large difference in electronegativity of the carbon and the oxygen atom. An anhydride C-O resonates between 1000 and 1300 cm-1 it is a at least two bands. The peak is present in the 13C NMR at 1269 and 1299 cm-1 it is of medium intensity.
The First stage in Erickson’s theory is trust vs. mistrust, this stage occurs during infancy, from birth to one years old. This stage is all about trust, it is the stage where you hopefully begin to trust not only yourself but others as well (Crandell and Crandell p. 36). An infant gains trust in infancy because they can not do anything for themselves, they depend on others to do everything for them therefore in this stage they develop trust in others, their caregivers, that they will do all that they can to take care of their well-being. Developing trust in infancy is crucial because this makes the individual grow up feeling safe and secure in the world. A positive outcome of an infant developing trust is that they grow up feeling safe in the world, a negative outcome would be that the individual grows up in fear of the world. There is no way to develop one hundred percent trust or one hundred percent doubt, Erikson believed that the best way to come out of this stage is with a balanc...
However, in set 7 all of the bond angles were 1.74 with the expection of ethyl chloride which had a 1.80 bond length. In problem set 4 there’re enthalpy values were extremely high compared to set 8 which were in the negatives as well but, the values were closer to the lower end. However, the enthalpy did result in negative values. Problem set 5 was the only set that added which atom bears the greatest positive charge in a particular iron which was unlike the other sets. Also, this set required 2 values to be reported and the question in of itself was a comparison. However, the values were really close. Each set had a negative and a positive number reported. It can be inferred that the odd carbon number bore a negative value. Like stated before, the values of the bond distance of each compound were fairly close to one another. However,although the spelling of the compounds were almost identical they were all different compounds and had different distances for each one. As stated before, set 7 reported all positive values. Although the charge of the carbonyl carbon was asked to be found for each of the four questions in this set, the compound in which the carbonyl carbon was attached to were all
The stages outlined by Erikson start with Trust vs. Mistrust, which is mostly dictated by the quality of relationship between the mother and infant. If the child allows their mother out of sight without becoming upset, the child displays trust. The next task is Autonomy vs. Shame. This stage consists of the child learning independence or feeling doubtful of their abilities. An example of autonomy within this stage would be the child saying “no” to virtually everything in an attempt to make their own choices. The next stage, Initiative vs. Guilt, is similar to the previous. It is characterized by the child attempting to formulate and carry out plans or feel guilty for trying to establish independence. Erikson’s next step, Industry...
+ 360 + (3 348) + 463 = 5575. Pentan-1-ol has eleven C-H bonds, 4 C-C bonds, 1 C-O bond and one O-H bond therefore the calculation would be: (11 412) + (4 348)+ 360 + 463 = 6747. Hexan-1-ol has 13 C-H bonds, 5 C-C bonds, one C-O bond and one O-H bond therefore the calculation would be: (13 412) + 360 + (5 348) + 463 = 7919. Heptan-1-ol has 15 C-H bonds, 6 C-C bonds, one C-O bond and one O-H bond therefore the calculation would be: (15 412) + 360 +(6 348) + 463 = 9091. Octan-1-ol has 17 C-H bonds, 7 C-C bonds, one C-O bond and one O-H bond therefore the calculation would be: (17 412) + 360 + (7 348) + 463 = 10263.
American psychotherapist, author and lecture Wayne Dyer once said, “Procrastination is one of the most common and deadliest of diseases and its toll on success and happiness is heavy.” When one procrastinates, they put things off to be done last minute, which then leads to stress, unhappiness and failure. As a college student Procrastination hinders my academic caree6r. Students procrastinate because they get distracted, overwhelmed by the task or just lazy, however students can overcome procrastination by developing a schedule, carefully planning academic task and improving time management. My personal experinces, O'Reilly, Sally’s article, and Edwin C. Bliss’s book will validate my panaceas to procrastination.
Procrastination has become a problem for some adults so there are several articles and studies showing ways to get rid of procrastinating habits. Jinny Ditzler, a writer for the Huffington Post, wrote about the ever-ending question “if one breaks their procrastination habits will it change their life for the better?” As stated before, a person might procrastinate because of their fear of “life-changing priorities [which] can be scary because they’re so big” (Ditzler 2015). Procrastination doesn’t happen because we want it too, it happens because our mind is trying to save us from experiencing a stressful task for as long as
The ring structure of an aromatic compound must be __coplanar, so this means that the atoms involved in the ring are on the same plane. Here, we can see that the carbon (gray) and hydrogen (white) atoms are all on the same plane.
Ionic compounds, when in the solid state, can be described as ionic lattices whose shapes are dictated by the need to place oppositely charged ions close to each other and similarly charged ions as far apart as possible. Though there is some structural diversity in ionic compounds, covalent compounds present us with a world of structural possibilities. From simple linear molecules like H2 to complex chains of atoms like butane (CH3CH2CH2CH3), covalent molecules can take on many shapes. To help decide which shape a polyatomic molecule might prefer we will use Valence Shell Electron Pair Repulsion theory (VSEPR). VSEPR states that electrons like to stay as far away from one another as possible to provide the lowest energy (i.e. most stable) structure for any bonding arrangement. In this way, VSEPR is a powerful tool for predicting the geometries of covalent molecules.
The procrastination problem of mine has been identified. I understand the reasons why I choose to procrastinate. I researched some of the most intelligent people's ideas on why people procrastinate and how to fix it. I even took the time to identify what I need to do, in order to prevent any procrastination. The only thing standing in my way is my will power to change. Today would be the best time to do it, however I think I'll wait until tomorrow.