How To Pass Organic Chemistry With Pictures

However, organic chemistry isn’t limited to living things. For example, the chemical reactions involved in the burning of fossil fuels fall under the O chem umbrella because these reactions involve carbon-based compounds in the fuels.

You’ll need to be familiar with Lewis structures before you begin. These are typically taught as part of a general chemistry course. In a Lewis structure, atoms in a molecule are represented by their chemical symbol (their letters on the periodic table). Lines represent the bonds between them and dots represent their valence electrons. See our Lewis structure article for a refresher. One way of drawing molecules that will probably be new to you is the skeletal formula method. In a skeletal formula (also called “bond-line structure”), carbon atoms are not shown. Instead, there is just a line to represent the bond. Since there are so many carbon atoms in O chem, this makes it much quicker to draw molecules. Non-carbon atoms are still represented by their chemical symbols. A good guide to skeletal formations is available here. [2] X Research source

In both Lewis structures and skeletal formulas, single bonds are represented by one line, double lines by a double line, and triple bonds by a triple line. In skeletal formulas, the bonds between carbon (C) and hydrogen (H) atoms are not usually drawn because they are so common. Except in special circumstances, atoms are typically only allowed to have eight valence (outer shell) electrons. This means that most of the time an atom can bond to a maximum of four other atoms.

A carbon bonded to four other atoms with single bonds will have the shape of a tetrahedron (four-pointed pyramid). A good example of this is the molecule methane (CH4) A carbon bonded to another atom with a double bond and two atoms with single bonds has a trigonal planar (flat triangle) shape. The ion CO3-2 is a good example here. A carbon bonded to two atoms with double bonds or bonded to one album with a triple bond has a linear (rigid line) shape. The molecule carbon dioxide (CO2) is one example.

Carbon is a perfect example of this. Carbon atoms have four valence electrons: two in the 2s orbital and two unpaired ones in the 2p orbital. Since there are two unpaired electrons, it might be expected that carbon will form two bonds. However, experiments show that the paired electrons in the 2s orbital form bonds even though they are not unpaired. Thus, we say that the carbon atom has four unpaired electrons in an sp hybrid orbital.

As you go up and to the right in the periodic table, atoms gain more electronegativity (hydrogen and helium are not included). Fluorine, the atom in the very top top right, has the highest electronegativity of all. Because electronegative atoms “want” more electrons, they tend to react by “grabbing” available electrons on other molecules. For example, atoms like chlorine and fluorine often appear as negative ions because they have taken electrons from other atoms. [3] X Research source

Organic chemistry isn’t hard—you just have to reach a point where you can easily visualize it. [4] X Expert Source Chris Hasegawa, PhDRetired Science Professor & Dean Expert Interview. 29 July 2021. Don’t let horror stories from people who have taken O chem before get to you. [5] X Expert Source Chris Hasegawa, PhDRetired Science Professor & Dean Expert Interview. 29 July 2021. Students tend to embellish how difficult their experiences were. Going into your first test terrified that you are facing an impossible challenge will only make things harder. [6] X Research source Instead, boost your confidence by spending plenty of time studying and getting plenty of rest the night before. O chem is not a math-heavy course. You will not have to do much arithmetic or algebra to pass this course. Rather, think of the subject more like learning a new language. [7] X Research source

However, if you are good at memorization, you can still use this to your advantage. Try writing basic reaction mechanisms on flashcards and using these to memorize the reactions. You’ll still need to be able to adjust your knowledge when you see reactions that you’re not familiar with, but you can use the basic principles to guide you towards the correct mechanism. Repetition is a great way to better understand organic chemistry. As you study, grab a whiteboard and draw things over and over again. [8] X Expert Source Chris Hasegawa, PhDRetired Science Professor & Dean Expert Interview. 29 July 2021.

There are too many functional groups in organic chemistry to list in this article. However, it’s not hard to find guides to the functional groups online. For example, a good guide from Purdue University is available here.

Nucleophile: a species that’s got extra electrons to share. Look out for negatively charged species, double bonds, or neutral species with lone pairs. Examples include hydroxide, pyridine, iodide, alkenes, enolates, and Grignard reagents. Electrophile: a species that is looking for a pair of electrons. Look out for partial or fully positively charged species. Examples include carbocations, hydrogen halide acids, haloalkanes, hydronium ions, and carbonyls. The diatomic halogens (Cl2, Br2) do not bear positive charges, but the bond between the two halogen atoms is weak and they are able to make stable anions, rendering them susceptible to nucleophilic attack. Radical: any species with uncharged electrons. This could include a bromine atom, for example. When these species react, they tend to make one “normal” molecule, along with another radical. Diene: a species that has two double bonds separated by a single bond (conjugated double bonds); these participate in pericyclic reactions. Common compounds of this type include furan, Cyclopentadiene, and 1,3-butadiene. Dienophile: a species that reacts with dienes in a pericyclic reaction. Look out for an alkene conjugated to a carbonyl group (an α,β-unsaturated carbonyl compound) such as ethyl acrylate, methyl vinyl ketone, or cyanoacrylate.

As one example, since oxygen (O) is more electronegative than carbon, the O that is double-bonded to C in a ketone group tends to hold the electrons in the bond closer to itself. This gives C a partially positive charge and makes it a good candidate to receive electrons. If you have a good electron donor involved in the reaction, it makes sense that it might attack the C, forming a new bond and kicking off your reaction.

Avoid walking into your professor’s office without a clear idea of what you want. Simply saying “I don’t get the homework” won’t get you useful help. Not only is this a great way of getting your questions answered — it can also help you get to know your professor. Keep in mind that if you’re aiming for grad school, you will need a few academic references in the future. Professors are much more likely to write positively of people that took the time to talk to them. If you can’t get a hold of your professor, then look around for their research lab and student office. Most professors employ a few graduate students in their labs, and they may be willing to help you with questions.

Molecular model sets allow you to build molecules out of plastic pieces. These can be somewhat expensive if you buy them from your school’s book store or a chemical supplier, but some professors will loan them out to students who ask for them at no cost. If you can’t get your hands on a “real” model set, try using foam balls, markers, and wooden dowels from your local craft store for a DIY alternative. Various computer programs (like the one available here) can also help you model molecules in three dimensions. [9] X Research source

Though there are many forums for these sorts of problems, chemicalforums. com is a good place to start. [10] X Research source

Khan Academy: Hosts numerous video lectures covering a variety of basic topics. [11] X Research source Chem Helper: Has links to practice tests, help forums, reaction mechanisms, and more. Also includes laboratory help. [12] X Research source University of South Carolina Aiken: Includes its own directory of helpful websites covering a variety of O chem topics.