Flashcards in Chapter 4 Deck (44)
Define saturated hydrocarbon
Hydrocarbons that contain only single bonds between carbon atoms.
-Simplest form of hydrocarbons
- Saturated bc each carbon atom is bonded to as many hydrogen atoms as possible
saturated hydrogen carbons with sigma (single bonds)
- can be in a chain or ring
What are the two types of alkanes?
Acyclic alkanes and cycloalkanes
Define acyclic alkanes
Linear and branched chains
- saturated hydrocarbon bc max number of hydrogens
Formula = CnH2n
- Makes a ring
- have 2 fewer Hydrogens than acyclic
What is an alkane's hybridization?
Sp3 and tetrahedral geometry
Two different compounds with the same molecular formula
What are the two main types of isomers?
Constitutional isomers and stereoisomers
Define constitutional isomers
molecules that differ in the way the atoms are connected to each other
Define alkyl group
Formed by removing one hydrogen from an alkane
Are alkanes polar or nonpolar?
- they only have c-c and c-h bonds
Do alkanes have lower or higher mp's and bp's than more polar compounds?
Lower mp and bp bc of less intermolecular forces
How does the mp and bp in alkanes increase?
Increasing the number of carbons increases surface area which increases mp and bp
Does branching on isomers increase or decrease bp?
Branching decreases bp bc less surface area
Does cymmetry increase or decrease mp?
Symmetry increases mp
The 3D structure of molecules
Where does rotation occur in organic molecules?
Around c-c sigma bonds
Different arrangements of atoms that are involved by rotation about single bonds
What are the two types of conformations?
Eclipsed and staggered conformations
Define eclipsed conformations
C-H bond on one carbon is directly aligned with the C-H bond of the adjacent carbon
Define staggered conformations
The C-H bond of one carbon bisects the H-C-H bond angle on the adjacent carbon
Define dihedral angle
The angle that separates a bond on one atom from a bond on an adjacent atom
Does a stable molecule have higher or lower energy?
Lower energy, it's not excited
Are staggered or eclipsed conformations more stable?
Staggered conformations are more stable (lower in energy)
Define torsional energy
The difference between staggered and eclipsed conformations
Define torsional strain
An increase in the energy caused by eclipsing interactions
Define anti rotations
Staggered conformation with two larger groups 180 degrees from each other
Define gauche rotations
Staggered conformation with two larger groups 60 degrees from each other
Define steric strain
An increase in energy resulting when atoms are forced too close to one another