Volatile Liquid Experiment

What is meant by a volatile liquid?

a liquid with a low boiling point

How is the mass of the volatile liquid established?

Using mass balance, mass of clean dry conical flask, rubber band and aluminium foil found.

After vaporised, allowed to cool and condense again, outside of flask and aluminium foil dried.

Mass of conical flask, rubber band and aluminium foil found again.

Subtract initial mass away from final mass of conical flask with vapour, this gives the mass of the volatile liquid.

How is the volatile liquid vaporised?

Placed in conical flask, submerged in a beaker completely full of water.

Hot plate used to heat the beaker of water close to boiling point. This will vaporise the volatile liquid

How is the temperature of the vapour found?

Thermometer placed in water

How is the pressure of the vapour found?

Barometer

Pressure will be the same as atmospheric pressure due to pinhole

How is volume of propanone found?

Fill conical flask that will be filled with vapour completely with water, pour into graduated cylinder, read its volume

Why is this method unsuitable for non-volatile liquids?

Boiling points of non-volatile liquids too high

What modern instrumental technique can be used to find the relative molecular mass of volatile and non-volatile liquids?

Mass spectrometry

Give 3 errors in this experiment that may lead to inaccurate results.

entire conical flask should be covered in boiling water

outside of conical flask and aluminium foil may not be completely dry when finding mass

mass balance may only read to an accuracy of one or two decimal places