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Flashcards in Chapter 4 Deck (44)
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1

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

2

Define alkane

saturated hydrogen carbons with sigma (single bonds)

- can be in a chain or ring

3

What are the two types of alkanes?

Acyclic alkanes and cycloalkanes

4

Define acyclic alkanes

Formula= CnH2n+2

Linear and branched chains

- saturated hydrocarbon bc max number of hydrogens

5

Define cycloalkanes

Formula = CnH2n

- Makes a ring

- have 2 fewer Hydrogens than acyclic

6

What is an alkane's hybridization?

Sp3 and tetrahedral geometry

7

Define isomers

Two different compounds with the same molecular formula

8

What are the two main types of isomers?

Constitutional isomers and stereoisomers

9

Define constitutional isomers

molecules that differ in the way the atoms are connected to each other

10

Define alkyl group

Formed by removing one hydrogen from an alkane

11

Are alkanes polar or nonpolar?

Nonpolar

- they only have c-c and c-h bonds

12

Do alkanes have lower or higher mp's and bp's than more polar compounds?

Lower mp and bp bc of less intermolecular forces

13

How does the mp and bp in alkanes increase?

Increasing the number of carbons increases surface area which increases mp and bp

14

Does branching on isomers increase or decrease bp?

Branching decreases bp bc less surface area

15

Does cymmetry increase or decrease mp?

Symmetry increases mp

16

Define stereochemistry

The 3D structure of molecules

17

Where does rotation occur in organic molecules?

Around c-c sigma bonds

18

Define conformations

Different arrangements of atoms that are involved by rotation about single bonds

19

What are the two types of conformations?

Eclipsed and staggered conformations

20

Define eclipsed conformations

C-H bond on one carbon is directly aligned with the C-H bond of the adjacent carbon

21

Define staggered conformations

The C-H bond of one carbon bisects the H-C-H bond angle on the adjacent carbon

22

Define dihedral angle

The angle that separates a bond on one atom from a bond on an adjacent atom

23

Does a stable molecule have higher or lower energy?

Lower energy, it's not excited

24

Are staggered or eclipsed conformations more stable?

Staggered conformations are more stable (lower in energy)

25

Define torsional energy

The difference between staggered and eclipsed conformations

26

Define torsional strain

An increase in the energy caused by eclipsing interactions

27

Define anti rotations

Staggered conformation with two larger groups 180 degrees from each other

28

Define gauche rotations

Staggered conformation with two larger groups 60 degrees from each other

29

Define steric strain

An increase in energy resulting when atoms are forced too close to one another

30

Are gauche or anti conformations more stable?

Anti conformations are more stable (lower in energy) bc less steric strain