General Chemistry Review

By James Ashenhurst

From Gen Chem to Organic Chem, Part 14: Wrapup

Last updated: March 21st, 2021 |

So what are the key concepts from General Chemistry that you need to apply to Organic Chemistry, going in? This past summer, I saw people asking this question on places like Yahoo Answers and SDN all the time. So I decided to do something about it. It was embarrassing how much 1st year chemistry I’d completely forgotten, but putting something like this together was helpful to solidify it again. If you really want to learn something, try teaching it – that goes for anything, by the way.

Anyway, from the perspective of someone going into Organic Chemistry, these are the key lessons I’d take away from General Chemistry:

  1. atoms are built up from protons, neutrons, and electrons, and the energies of electrons are quantized – they ascend not gradually (like a ramp) but in discrete levels (like stairs)
  2. electrostatic attraction and repulsion is the fundamental force that underlies all of chemistry, from the octet rule, the formation of chemical bonds, and even in determining periodic trends in properties like ionization energies and electronegativity
  3. there is a driving force for atoms to satisfy  the octet rule, and Lewis structures are the tool we use to visualize the number of electrons surrounding each atom in a molecule.
  4. chemical bonding ranges across a scale from ionic character (where there is vastly unequal sharing of electrons) to covalent character (in which electrons are shared equally)
  5. there are important chemical behaviors called acidity and basicity and two important definitions of each – in the Brønsted definition, an acid is a species that donates a proton (H+) and a base accepts a proton; in the broader Lewis definition, an acid accepts an electron pair and a base donates an electron pair.
  6. thermodynamics is the study of the exchange of energy between atoms/molecules and their environment; using standard tables, we can use Hess’ law to calculate the enthalpy (heat) change for a reaction, or if tables are unavailable, approximate it by making calculations based on the energies of the bonds broken and formed.  The measure of whether a reaction is favorable is the Gibbs energy, ΔG – which takes entropy into account – and as temperature is increased, the entropy factor will begin to favor processes that lead to an increase in entropy, like gas formation and fragmentation reactions.
  7. the rate of a chemical reaction depends on 1)temperature, and 2) the concentrations of the reactants in the slowest step of the mechanism (the rate-determining step).  By studying reaction rates we can gain insight into reaction mechanisms, as well as determine the activation energy of a process.
  8. reactions which proceed with no net change in the concentration of reactants or products are in equilibrium. We can use the equilibrium constant to figure out the ΔG for a process using the van’t Hoff equation. Small differences in ΔG can lead to huge differences in the direction of the equilibria! We can also use Le Chatelier’s principle to manipulate chemical equilibria to drive it in the direction we desire.

Here’s a list of all the posts:

“General Chemistry and Organic Chemistry: How Are They Different?”

“From Gen Chem to Organic Chem, Part 1: The Atom”

“From Gen Chem to Organic Chem, Part 2: Electrons and Orbitals”

“From Gen Chem to Organic Chem, Part 3: Effective Nuclear Charge”

“From Gen Chem to Organic Chem, Part 4: Chemical Bonding”

“From Gen Chem to Organic Chem, Part 5: Understanding Periodic Trends”

“From Gen Chem to Organic Chem, Part 6: Lewis Structures, A Fable”

“From Gen Chem to Organic Chem, Part 7: Lewis Structures”

“From Gen Chem to Organic Chem, Part 8: Ionic and Covalent Bonding”

“From Gen Chem to Organic Chem, Part 9: Acids and Bases”

“From Gen Chem to Organic Chem, Part 10: Hess’ Law

“From Gen Chem to Organic Chem, Part 11: The Second Law of Thermodynamics”

“From Gen Chem to Organic Chem, Part 12: Chemical Kinetics”

“From Gen Chem to Oranic Chem, Part 13: Equilibria”

Even though I’m the world’s worst graphic designer, I could probably put these together as a PDF if enough people are interested. Hope it’s useful!


Comment section

11 thoughts on “From Gen Chem to Organic Chem, Part 14: Wrapup

  1. Nothing wrong with going back to the basics and having them solidly in place. As nascent MDs are told about looking up the correct dosage for a drug “Don’t be proud, be accurate”

  2. My first semester of college just ended and I was googling my courses for next semester. I’m glad I found your site now I have something to prepare me for O Chem!

  3. your reviews are awesome! I have my ochem final tomorrow, and your reviews are a great way to go over what we’ve learned through the semester! Great job with the analogies, btw. Thanks for taking the time to create this website, Im going to recommend it to my friends :D

  4. I am taking o chem this upcoming fall semester and have been really stressing out about not doing well in this course since I had some bad professors for general chem my freshman year. This website and all these descriptions has been super helpful to help me review the basics of gen chem and I have bookmarked it so I can use it during the school year as well for o chem! I have already sent all my friends and fellow bio and chem majors the link! Thanks so much for taking the time to make this website!!! Truly wish there were more caring professors who would spend their time wanting to help students succeed like you!!

  5. you are a God send! I’m not that good in Gen Chem…taking Ochem in august this Gen Chem to OChem is the Chem-Bible for me!

  6. You mentioned that taking Physics before taking Organic Chemistry would be a good idea. I am a Freshman in college and just finished taking Gen Chem II: I finished the class with a “C” (mostly because my professor didn’t lecture very much- we had to teach ourselves via video), and lab with an “A”. I have registered for Organic Chem next semester, but thinking that since I did not have Physics in high school I should consider it at this point. What are your thoughts? If, Physics, should I take Conceptual Physics, or Physics 1? By the way, thank you for making this website. I am so glad that I found it now!

  7. Dear James,
    It’s so hard for me to study Chemistry at University since I finished high school from 1985. But I feel very confident and so happy to do it from the time I have found your website “Master Organic Chemistry”. It’s so wonderful and has helped me a lot!
    Thank you so much and wishing you all the best of health!
    Tien Vu Balogh

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