How many hydrogens are attached to each of the indicated...

Key Concepts

Carbon Valency

Carbon atoms generally form four covalent bonds. This fundamental property determines how many hydrogen atoms can be attached to a given carbon atom, depending on how many other bonds it forms with other atoms or groups. In determining substitution levels within molecules, including complex structures, this concept is essential.

Hybridization

The hybridization state of a carbon atom (sp3, sp2, or sp) affects its bonding geometry and the number of hydrogen atoms it can bond with. For instance, an sp3 hybridized carbon forms tetrahedral structures that can accommodate varying numbers of hydrogen atoms based on its substitution pattern.

Implicit Hydrogen Counting

In organic chemistry, molecular structures are often represented by skeletal formulas where hydrogen atoms bonded to carbon atoms are not explicitly shown. Chemists use the carbon's valency and the existing bonds to deduce how many hydrogens are attached to each carbon, an important skill when analyzing molecular structures.

Ring Structures in Organic Molecules

Many bioactive compounds, such as morphine, feature ring structures. The arrangement and connectivity within these rings influence the degree of substitution on each carbon. Understanding how carbons are integrated into cyclic systems is crucial for accurately determining the number of hydrogens attached to each carbon atom.

Transcript

00:01 Okay, this problem is asking us how many hydrogens are on each of these indicated carbons of morphine.

00:05 So the molecule that i've drawn out in blue is morphine, and then what is drawn in red, those are just arrows.

00:10 I was just too lazy to draw the head of the arrow.

00:14 Okay, but in green i'll be representing the hydrogens.

00:17 Okay, so attached to, i'll start with the bottom left, attached to this carbon.

00:21 That carbon has a bond this way, two bonds that way and a bond that way.

00:26 So again, we want to have all carbons have a full octet, and they can.

00:30 Can achieve that by having four bonds each.

00:32 So because i have a single bond, a single bond, and a double bond, double, single, that corresponds to four bonds.

00:39 None of them are connected to hydrogens, so this one would be zero.

00:43 Okay, and then moving along this way, same thing this way.

00:45 This one is connected to an oxygen, single bonded, carbon that way, and double bond that way.

00:50 None of them are hydrogens, so that one would be zero.

00:53 Okay, what about this one? so that one, let's see.

00:57 We have a carbon bond, a single bond, carbon single bond.

01:00 Carbon single bond, but what about anything else? we don't have any other, we don't have a double bond anywhere, we don't have any single bonds outstretched to another atom, so we know that that must have an implicit hydrogen, right? one that's not shown, so that would be one.

01:16 Okay, what about this one? so that one has three bonds.

01:20 We have one single bond going that way, one going that way, and one going that way, but we don't have a fourth bond.

01:24 And we know that in order to achieve a full octet, they must have four bonds, because i only have three bonds there, that must mean that there is one hydrogen that is not shown.

01:32 So we have one there.

01:33 What about this one? that one, we have a bond that going that way, and then a bond going that way.

01:39 We have two bonds.

01:40 So we need two more.

01:41 That means that we must have two hydrogens there...

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