Unit 12: Introduction to Organic Chemistry
Why carbon builds more compounds than every other element combined, and the naming and shape rules that organize its endless chains and rings.
7 topics · 29 questions
Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.
12.1 Why Carbon Forms So Many Compounds
- How it worksHow does carbon's four valence electrons let it bond to up to four other atoms at once, including other carbons?
- How it worksHow does carbon's ability to form long chains and rings set it apart from every other element on the periodic table?
- Common mistakeWhy isn't carbon unique because it's more reactive than other elements, but because of how it bonds?
- Going furtherWhat happens to the number of possible compounds as a carbon chain gets one atom longer?
- Ties togetherHow does carbon's four bonding sites explain both its huge compound variety and alkane chain naming?
Your turn1 of 2
Chemists have identified and catalogued millions of distinct carbon-based compounds, while most other elements on the periodic table form only a small handful of stable compounds each. Why does carbon alone build millions of different compounds while most elements build only a handful?12.2 Naming Simple Alkanes
- How it worksHow does an alkane's prefix tell you exactly how many carbons are in its chain?
- How it worksWalk me through counting carbons and hydrogens to see why pentane, the five-carbon alkane, has the molecular formula C5H12.
- Going furtherWhat happens to an alkane's molecular formula each time you add one more carbon to its chain?
Your turn1 of 2
An alkane's molecular formula follows the pattern CnH(2n+2). If an alkane has 14 carbon atoms in its chain, how many hydrogen atoms does it have?12.3 Alkenes, Alkynes, and Multiple Bonds
- How it worksHow does a double or triple bond between carbons change a hydrocarbon from an alkane into an alkene or alkyne?
- How it worksWalk me through comparing the double bond in ethene to the triple bond in ethyne, carbon by carbon.
- Common mistakeWhy doesn't a carbon-carbon double bond behave like two separate single bonds you could rotate freely?
- Going furtherWhat happens to a hydrocarbon's reactivity when a single bond becomes a double or triple bond between two carbons?
Your turn1 of 2
A ripening banana releases a small amount of ethene gas, and placing that ripe banana next to unripe fruit noticeably speeds up how quickly the neighboring fruit ripens too. Why does a ripening fruit release a gas that ripens the fruit sitting right next to it?12.4 Structural and Skeletal Formulas
- How it worksHow does a skeletal formula hide every carbon and hydrogen at the end of each line without losing information?
- How it worksHow do chemists infer the number of hydrogens implied at each carbon in a skeletal formula without drawing any of them?
- Common mistakeWhy isn't a molecular formula like C6H14 enough to tell you the exact shape of a molecule?
- Going furtherWhat happens to a skeletal formula's line pattern once you add a functional group like an -OH?
Your turn1 of 2
A skeletal formula for a complex organic molecule shows only a zigzag of plain lines with almost no letters written at all, yet a chemist can still read off the complete molecular structure from that sparse drawing. Why do chemists draw just zigzag lines instead of every single carbon and hydrogen in a molecule?12.5 Isomers
- How it worksHow does rearranging the same atoms into a different connectivity create a structural isomer?
- How it worksHow does the number of possible isomers grow rapidly as a hydrocarbon chain gets longer?
- Worked exampleDraw two different structural isomers with the molecular formula C4H10.
- Common mistakeWhy aren't two isomers just the same molecule drawn two different ways?
- Going furtherWhat happens to a compound's boiling point and other properties when its atoms are rearranged into a different isomer?
Your turn1 of 2
Butane and isobutane both share the identical molecular formula C4H10, yet butane is a straight chain while isobutane is branched, and the two compounds have measurably different boiling points. Why can two molecules share the exact same molecular formula but behave completely differently?12.6 Common Functional Groups
- How it worksHow does a functional group like -OH or -COOH give a whole family of molecules the same chemical behavior?
- How it worksHow does the same -OH functional group show up in molecules as different as ethanol and glucose?
- Worked exampleFind the functional group present in acetic acid, CH3COOH.
- Common mistakeWhy doesn't the carbon backbone of a molecule determine its chemical behavior as much as its functional group does?
Your turn1 of 2
Ethane is a flammable gas used as a fuel, while ethanol, the exact same two-carbon backbone with a single -OH group attached, is the alcohol found in beverages people drink. Why does adding one -OH group to a hydrocarbon turn a fuel into something you can drink?12.7 Polymers from Monomers
- How it worksHow do small monomer units link together end to end to build one giant polymer chain?
- Worked exampleFind the monomer that links together to form the polymer polyethylene.
- Common mistakeWhy isn't a polymer simply a mixture of its monomer building blocks?
- Ties togetherHow does linking small monomers into one giant polymer chain echo the same carbon-bonding versatility that made this whole unit's variety of compounds possible?
Your turn1 of 2
A polymer chain is built from 13944 repeating monomer units linked end to end, with each monomer contributing 8 atoms to the chain. About how many total atoms are in the polymer chain's backbone, ignoring the few extra end-group atoms?