Introduction to Organic Chemistry - Online Tutor, Practice Problems & Exam Prep

Introduction to Organic Chemistry Concept 1

Hey everyone. So in this video, we're going to take a look at understanding organic chemistry. Now, organic chemistry is the study of structure, properties, and reactions of carbon-containing compounds. A key feature of organic compounds is that they possess carbon single bonded to carbons and carbons single bonded to hydrogen bonds. Here, we're going to say that hydrocarbons are organic compounds that contain only carbons and hydrogens. Many organic compounds can also contain other types of elements, including oxygen, nitrogen, sulfur, and the halogens. Below, we just have some typical types of organic compounds.

Now, for the first one, we're talking about propane. Propane is a hydrocarbon, meaning it's made up of only carbons and hydrogens. Here, the 3 carbons in the center would be surrounded by hydrogens. We can find propane in propane tanks, which are used for barbecues and other things that we use in everyday life.

Next, we have ethanol. Ethanol possesses an oxygen now. Like before, we have carbons connected to hydrogens, but now we also have the inclusion of an OH group. Ethanol is a key organic compound that we find in wine.

Next, we have the molecule for caffeine. We can see that this one is even more complex. We have carbons, nitrogens; we have double bonds here, here, here, here; we have nitrogens. So, caffeine is an important component of coffee.

And finally, here, we have geraniol. This is an important organic compound that we find in roses. This also contains pi bonds, double bonds, and another OH group, and as usual, a bunch of carbons connected to carbons and carbon-hydrogen bonds. So just remember when we're talking about organic chemistry, we're talking about reactions dealing with compounds containing hydrogen. A key feature of many organic compounds is carbons connected to carbons and carbons connected to hydrogens, and sometimes sprinkled in other types of elements.

Introduction to Organic Chemistry Example 1

Which of the following is an organic compound? Remember, a key feature of an organic compound is the presence of carbon connected to carbon, and also carbon connected to hydrogen. If we take a look at A, we don't have any carbons, we have no hydrogens. The same thing can be said for B, and C. The answer here is option D. That's because we have carbon-hydrogen bonds, we have carbon-carbon bonds, we also have carbon connected to this OH group. But remember, the fundamental thing we have to think about when it comes to many organic compounds is the presence of carbon-carbon bonds and carbon-hydrogen bonds, which this has.

Tetrachloroethane (C₂H₂Cl₄) has been used as an industrial solvent to produce paint removers and pesticides. It is classified as an organic compound. Which feature of this molecule makes it organic?

• A. C–Cl bond
• B. H–Cl bond
• C. C–H bond
• D. Cl–Cl bond

Structural Diversity Concept 2

When it comes to organic compounds, we can see that they have a lot of structural diversity. Now here, we can say this is a result of carbon. Carbon can make very stable carbon-carbon bonds due to high bond energy and short bond length. This leads to the formation of chains, branched structures, and rings in organic compounds. So here let's just take a look at some of these examples of structural diversity.

If we take a look here, we have a hydrocarbon; it's composed of only carbons and hydrogens, and it is a straight chain. So we have these 4 carbons in a chain together, and they just have these hydrogens branching off of them. Well, they're not branching groups; they're coming off of the carbon. The carbons themselves are a straight chain. Now, if we take a look at the next one, we have these carbons in a straight chain, and now we have a carbon that's off of the main chain, that's a branching group. So here we'd have this CH₃ portion as a branching group. And then finally, we have a ring, where the 4 carbons form a square here; they form a cyclic or ring structure.

So remember, carbon-carbon bonds can happen and form these different types of structurally diverse molecules or compounds because of high bond energy and short bond length.

Structural Diversity Example 2

In this example question, it states, "Which of the following statements is incorrect about the structural diversity of organic compounds?"

A: Carbon can form strong double and triple bonds. That's true; we can do that.

B: The small atomic radius of carbon ensures sufficient orbital overlap to form strong bonds. So a small atomic radius would lead to small or short bond lengths. We said that this is one of the key features that leads to structural diversity when it comes to carbon-carbon bonds. So this is true.

C: Carbon can form stable chains up to 12 atoms only. Not once did we talk about there being a limit to the number of carbons we can have within the chain. So this statement here is not correct. So this would be our answer.

D: Organic compounds containing other elements such as oxygen, nitrogen, or sulfur are very common. We've seen that when it comes to organic compounds, the key feature is a carbon-carbon bond and a carbon-hydrogen bond. But we also know that organic compounds can contain other elements, such as oxygen, nitrogen, sulfur, or the halogens. These are pretty common within nature and within labs. So here, option D is correct. Including these other elements leads to greater structural diversity.

So here, option C would be our final answer.

Which of the following compounds has the most branched structure?

• A.
• B.
• C.
• D.