3 – Measuring the Relative Molecular Mass of a Volatile Liquid (LC 2027) (Leaving Cert Chemistry): Flashcards
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Practise the cards
13 cards from this deck
Property of volatile liquids
Property of volatile liquids
Low boiling points
Purpose of pinhole in aluminium foil
Purpose of pinhole in aluminium foil
Allows vapour escape; maintains atmospheric pressure
What is weighed initially
What is weighed initially
Clean, dry flask with foil and rubber band
Temperature measured in experiment
Temperature measured in experiment
Temperature of boiling water
What final mass - initial mass gives
What final mass - initial mass gives
Mass of liquid whose vapour filled the flask
Volume of vapour in flask equals
Volume of vapour in flask equals
Volume of the flask itself
Pressure inside flask during heating
Pressure inside flask during heating
Equals atmospheric pressure
Safety: where to work with volatile liquids
Safety: where to work with volatile liquids
Well-ventilated area
Advantage of this method
Advantage of this method
Cost-effective alternative to mass spectrometry
Limitation: type of substances suitable
Limitation: type of substances suitable
Only volatile substances with appropriate boiling points
Why complete vapourisation is essential
Why complete vapourisation is essential
For accurate results
Why flask must be completely dry initially
Why flask must be completely dry initially
To ensure accurate mass measurements
Fundamental principle: Avogadro's Law
Fundamental principle: Avogadro's Law
Equal volumes of gases have equal numbers of molecules
