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General Chemistry Review

By James Ashenhurst

Gen Chem and Organic Chem: How are they different?

Last updated: March 21st, 2019

After finishing my freshman year of college, I spent my summer in the university town where I went to school. I had a menial telemarketing job along with some volunteer lab work on the side. Life was pretty easy: many of my friends had also decided to hang around, and there was lots of time for parties, TV,  and evenings spent on patios. However, sometime around early July, I started getting this nagging, anxious feeling about the coming semester. I had heard so many second and third-hand stories about the Dreaded Orgo Beast and how it was going to start devouring my life come September. Out of fear, I decided to buy a used textbook off a friend and start going through it at a leisurely pace throughout the following two months.

Many years have passed since then, but fear of the Beast still lives.  During the summer, I see these types of questions come up a lot:

1) Is Orgo Hard?

2) How is Organic Chemistry different from Gen Chem?

3) If I want to get ahead in organic chemistry over the summer, what should I do?

Let’s focus on the second question for now.

Gen Chem and Organic Chem: How are they different?

As you are probably aware, organic chemistry is the study of carbon-containing compounds, but if you haven’t taken the course yet, it won’t be a very helpful distinction. Looking at it from a big-picture perspective, I’d say the one tremendous difference you’ll find in organic chemistry is that it is very qualitative. Whereas gen chem has a large number of formulae and calculations to do, organic chemistry is notable in the absence of a lot of calculation work. You could easily write out all the formulae you would ever use in Org1/Org2 on the back of one hand.

Here are some of the types of questions you will typically not encounter in organic chemistry:

  1. calculating thermodynamic enthalpies/entropies
  2. electrochemical calculations
  3. calculating pH using the Henderson-Hasselhoff Hasselbach equation
  4. Ideal gas law questions
  5. rate constant calculations
  6. calculating equilibrium constants.

Before you say, “Hooray!” too loudly, a word of warning: in organic chemistry your professors will assume that you understand this stuff, and you can calculate it if you really have to. They will expect that you understand these topics on a conceptual level. What does that mean? It means you should be able to intuitively understand things like:

  • what happens to an equilibrium if the concentration of the product is changed
  • the effect of changing the concentration of a reactant in a second-order reaction on the reaction rate
  • how bonding interactions change with electronegativities
  • what happens to the Gibbs free energy term of a reaction as the temperature is varied.
  • how properties like electronegativity, electron affinity, ionic radius, etc. change as you go across the periodic table.
  • And so on.

That’s what I mean by a qualitative understanding. Feel comfortable answering those types of questions? If yes, you’re probably set. If not, here’s the plan at “Master Organic Chemistry” for the next few weeks.

“How Gen Chem ties into O-Chem”

There are really six main areas in general chemistry that come back again in organic chemistry. Over the next while I’ll be focusing each of these six topics in turn, and demonstrating how the concepts you learned in Gen Chem will become relevant to what you’re going to learn in Organic Chem come this fall.[Edit: I’ll be doing a post in this series every Monday for the next 6-8 weeks]

  1. Atomic properties
  2. Bonding
  3. Thermodynamics.
  4. Kinetics.
  5. Acids and bases.
  6. Equilibria.

Topics such as electrochemistry, ideal gases, molality, phase diagrams and so forth don’t really make much of an appearance in Org1/Org2. Which isn’t to say they aren’t important to organic chemistry – they can be – they just don’t come up much in the course.

As always, I’d be thrilled to hear any comments/suggestions.

Stay tuned!

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Comment section

16 thoughts on “Gen Chem and Organic Chem: How are they different?

  1. Thanks for finding my blog and pointing me in this direction! I didn’t care for General Chem and I’ve been dreading Orgo, because of that. I’ll definitely being using the resources here to do a little prep work prior to fall semester!

  2. Hey, thanks for putting this up. I’m going to be a senior in high school next year and am going to be taking AP chemistry. My plan is to major in something chemistry related and get a masters degree so this was helpful.

  3. Just found your website. Will be taking organic over the summer. Are there any other general chemistry concepts that would be expected knowledge in organic chemistry? Thanks!

  4. I cannot thank you enough for posting this! It’s been a month since break from my first year of college and now the trepidation of taking orgo is setting in! I reviewed all these concepts and started reading my orgo book for fall semester. Thank you so much for putting in the effort for this site! I will definately be using it through the summer and when the course begins!

    1. Great – glad you’re finding it useful. You might also find Daily Orgo Tips helpful – they walk you through introductory organic chemistry, one day at a time.

  5. i am looking for some advise in regards to orgo – i took intro to chem years ago then i took chem 1 last semester (i made an 89 in the class). i found out that you can take orgo without chem 2 if you have a bachelors degree. i only need orgo to apply for a masters program so do you think a person can do well in orgo without chem 2? i don’t know if i should just suffer through a whole semester of chem 2 then take orgo or if i should just jump into orgo and give it my best. any advise on the matter would help so much! thank you for your time!!

    1. It’s hard to say. Depends on how intense your organic chemistry course is. I tried to summarize the main points from gen chem that appear in organic chem in the series here. Jared from Subway lost 200 lbs through eating sandwiches and walking, but that might not work for everyone.

  6. Hey I feel like you are ignoring the difference on the meaning of reduction /oxidation between the classes

  7. I’m taking orgo next semester and am about to lose all the hair on my head :( Gen Chem was okay….but I’m scared for orgo :(

  8. I actually just finished taking o-chem 1 and 2 this summer, and got a 100 in both. I’ve actually never taken general chemistry before, I’m fairly confident it’s safe to say that all the genera chemistrt you need should be reviewed the first few days of class. I don’t know if I would recommend doing what I did, but I decided earlier this year that I wanted to go to medical school and in order to stay on track I kind of had to do it this way.

  9. I won’t tell you about the Physicians in my family for generations or the phenomenal Physicians whom I’d like to emulate and help in their pursuit of Integrative Primary Healthcare, because without my mastery of gen chem and o chem- none of that will come to fruition. Help


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