Three watch glasses are put under a record electronic camera. A brown paper towel works simply too. A brown paper towel provides much better shade comparison of the liquid spots and the rate of evaporation compared to a white paper towel. A drop of water, a drop of ethanol, and a drop of acetone are put on sepaprice watch glasses or in sepaprice locations of the paper towel and the price of evaporation is oboffered. The drop of acetone evaporates a lot faster than the ethanol which evaporates quicker than the drop of water.

You are watching: Why does acetone evaporate faster than ethanol

Setting the phase before doing the demonstration: Have students predict which liquid will certainly evapoprice fastest and also the slowest. Have students describe their options.

• Which liquid will evapoprice the slowest? The fastest? Exordinary.

What components determine just how fastor sluggish a liquid will certainly evapoprice at room temperature?

• It will help to draw the Lewis structures of each molecule,recognize if the molecule is polar or non-polar, and calculate the molecular mass of each compound.
• It will certainly assist to recognize the types of intermolecular forces of attraction current between molecules.

Sample student information table

Rate of evaporation versus type and strength of IMF

 Type of IMF Strength of IMF Relative Rate of Evaporation Acetone Ethanol Water

 Strengths ofIMFs Vapor Prescertain (kPa) at 20°C Melting Point (°C) Acetone medium 28 -95 Ethanol medium- strong 5.95 - 114 Water strong 2.33 0.0

 Strengths of IMFs Hvap(kJ/mol) Boiling Point (°C) Acetone medium 30.3 +56.5 Ethanol medium- strong 39.3 +78 Water strong 40.6 +100

A collection of Power Point Slides to acfirm this demonstration is available in the right food selection.

This demo is probably best used as soon as mentioning intermolecular forces. Students regularly believe the molecular mass of a compound is the major factor governing physical properties, such as boiling allude and evaporation.

Learning Objectives

1. Identification of intermolecular pressures operating within liquid samples of water, ethanol, and also acetone and the correlation of a physical home, rate of evaporation, with the type and toughness of the IMF in the liquid.

One day of lead time is required for this job.
Discussion

Acetone evapoprices a lot quicker than water, even though its molecular mass is more than three times as much. Water molecules, in the liquid and also solid state, are qualified of hydrogen bonding, whereas a repertoire of acetone molecules in the liquid state carry out not. The relatively strong hydrogen bonding between water molecules slows the evaporation rate and increases the surconfront tension, as shown by acetone's flatter drop form on the watch glass. Ethanol exhibits hydrogen bonding between ethanol molecules but does not evaporate as conveniently as water.

document cam or overhead projector and also display (for a medium to large lecture hall)3 tiny watch glasses or a brown paper towelthree dropper bottles via stoppers or lids, one containing water, one containing ethanol, one containing acetone

The 3 watch glasses are inserted on the overhead projector. A drop of water, a drop of ethanol, and also a drop of acetone are inserted on sepaprice watch glasses and also the rate of evaporation is oboffered. The drop of acetone evapoprices much faster than the drop of water or the ethanol.