Lesson 11: Organic Compounds-Structural/Constitutional Isomerism

What classification system was used for compounds in the early 1800s?

In the early 1800s, compounds were classified as organic (from living sources) and inorganic (from nonliving sources).

How were organic compounds described in the early 1800s in terms of purification and decomposition?

Organic compounds were hard to purify and easily decomposed when heated.

What did scientists in the early 1800s believe was responsible for the formation of organic compounds?

Scientists believed in a “vital force” found only in living things — a belief known as the vitalism theory.

Who was the German chemist that challenged the vitalism theory, and when did this occur?

In 1828, German chemist Friedrich Wöhler challenged the vitalism theory.

What experiment did Friedrich Wöhler perform in 1828 that challenged the vitalism theory?

In 1828, Friedrich Wöhler converted ammonium cyanate (an inorganic compound) into urea (an organic compound).

organic compounds

contain carbon

inorganic compounds

lack carbon.

Mid-1800s: three scientists developed the structural theory of matter.

Kekulé, Couper, and Butlerov proposed that each substance is defined by a specific atom arrangement.

Their work explained how different structures give rise to different compounds, even with the same formula.

Constitutional Isomers

compounds have the same molecular formula , yet they differ from each other in the way the atoms are connected— that is, they differ in their constitution

Constitutional isomers have different physical proper ties and different names.
The first compound is a colorless gas used as an aerosol spray propellant,

while the second compound is a clear liquid, commonly referred to as “alcohol,” found in alcoholic beverages

In structural theory of matter, each element will generally form a predictable number of bonds

Tetrahedral, Trivalent, Divalent, Monovalent

Tetrahedral

carbon generally have four bonds.

Trivalent

Nitrogen generally forms three bonds

Divalent

oxygen generally forms two bonds

Monovalent

hydrogen and halogens generally form one bond