My Easy Science
Ethanol (C₂H₅OH), Five Ways
One molecule, five views. Pick a view on the left to see the same ethanol molecule drawn a different way. Each drawing on this page is drawn fresh for this site.
Five views of ethanol
Tap a view to switch. The link updates, so you can share the exact view you are looking at.
Ethanol is two carbons joined together. The second carbon carries an OH group. That OH is called the hydroxyl group, and it is what makes ethanol an alcohol.
The H of one OH group is pulled toward the O of the next molecule. Those dashed lines are hydrogen bonds. They are why ethanol needs more heat to boil than a similar sized molecule without OH groups.
Same molecule as balls and sticks. The CH₃ end is the methyl group, the CH₂ middle is the methylene group, and CH₃CH₂ together is the ethyl group. Colours: dark grey = carbon (C), red = oxygen (O), light grey = hydrogen (H).
Chemists switch between these all the time. Condensed writing is fastest, the skeletal drawing is shortest, and the two 3D styles show the real shape. Colours: dark grey = carbon (C), red = oxygen (O), light grey = hydrogen (H).
One way to make ethanol in industry is to add water across the double bond of ethylene. The double bond opens, and the OH lands on one carbon. C₂H₄ + H₂O → CH₃CH₂OH
View 1 of 5: Structure & hydroxyl group.
How it works
Ethanol is CH₃CH₂OH: two carbons joined together, with the second carbon carrying an OH group. That OH is the hydroxyl group, and it is what makes ethanol an alcohol. Because the OH end can form hydrogen bonds with water, ethanol mixes freely with water, while the CH₃CH₂ end behaves like a small hydrocarbon. The same molecule can be drawn in many ways, and chemists switch between them depending on what they want to show: the full structural formula spells out every atom, the condensed formula (CH₃CH₂OH) is fastest to write, the skeletal drawing is the shortest, and the ball-and-stick and space-filling models show the real shape.
Worked example: counting the atoms
Look at View 1 and count what is attached to each carbon. The left carbon has three hydrogens (CH₃), the right carbon has two hydrogens plus the OH group (CH₂OH). Add them up: 2 carbons + 6 hydrogens + 1 oxygen = C₂H₆O, which is written as C₂H₅OH to show the hydroxyl group. Its molar mass is 2 × 12.01 + 6 × 1.008 + 16.00 = 46.07 g/mol. Now look at View 2: the dashed lines show the H of one OH group being pulled toward the O of the next molecule. Those hydrogen bonds are why ethanol boils at 78.4 °C, far higher than ethane (C₂H₆, −88.6 °C), a molecule of almost the same size with no OH group.
All diagrams on this page are original drawings made for this site. They are not copied from other websites.
For learning only. Not for patient care decisions. Always check with a qualified professional and the product label.