## 11.3: Condensed Structural and Line-Angle Formulas

To describe organic compounds, chemists use a variety of formulas. Condensed structural formulas are difficult to type/write and take up a lot of space; a line-angle formula, in which carbon atoms are implied at the corners and ends of lines, is even more abbreviated.

### Key Takeaways

Condensed chemical formulas show hydrogen atoms (or other atoms or groups) right next to the carbon atoms. Draw the Lewis structure of the molecule below, showing all atoms and all valence electrons (bonds and lone pairs). Draw the Line-Angle structure for the compound below.

## What is the line angle structure?

A line-angle formula, also known as a skeletal structure, is even more abbreviated, with carbon atoms implied at the corners and ends of lines and each carbon atom understood to be attached to enough hydrogen atoms to give each carbon atom four bonds.

## What is the formula to find the angle of a line?

The angle of inclination of a line is the angle formed by the intersection of the line and the x-axis. Using a horizontal “run” of 1 and m for slope, the angle of inclination, theta=tan-1(m), or m=tan(theta), can be found if one of the equations is known.

## What is a shorthand formula?

The skeletal formula of an organic compound, also known as the line-angle formula or shorthand formula, is a type of molecular structural formula that serves as a shorthand representation of a molecule’s bonding and some molecular geometry details.

## What is a line angle?

When two lines intersect, an angle is formed. An angle has two legs and one common vertex where the two lines meet. For example, when lines AB and CD intersect, the angle AOD is formed.

## What are the types of structural formulas?

Empirical formulas show the simplest whole-number ratio of atoms in a compound, molecular formulas show the number of each type of atom in a molecule, and structural formulas show how the atoms in a molecule are bonded to each other, and structural formulas show how the atoms in a molecule are bonded to each other.

## What is the formula of Propyne?

This formula is full of bonds and lines, and because of the typical (more stable) bonds that atoms make in molecules, they often end up looking like zig-zag lines. This is done because it is not always clear whether the non-carbon atom is surrounded by lone pairs or hydrogens.

## How do you calculate an angle?

To find the two angles opposite the altitude, divide the opposite side by the hypotenuse and use the sine (opposite side divided by hypotenuse).