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- The name ebulliometer has its roots in the latin word "ebullio" : meaning to boil or bubble up.
- An ebulliometer is designed to accurately measure the boiling point (temperature) of water or a water solution, by measuring the temperature of the vapour generated away from the heat source (see diagram)
- An ebulliometer was first used to determine the molecular weights of substances, by measuring the changes in the boiling point of water cause by the presence of the unknown substance. (more)
- An ebulliometer apparatus consists of -
1. - A chamber to hold the liquid whose boiling point is to be determined, designed to allow for a semi-remote heat source.
2. - A condenser (reflux), to continually condense the vapour generated, to maintain the initial concentration of the liquid being tested.
3. - A special, precision thermometer (Churchward), calibrated in 0.02oC with a range of 95 - 115oC
A special bent thermometer can also be used. The bend thermometer is able to accommodate a horizontal sliding scale with a zero pointer, allowing an approximate (+/- 0.1% v/v) alcohol concentration level to be read directly of the scale.
4. - A heat source such as a spirit (alcohol) burner.
5. A heat chimney/shield to promote efficient burning by drawing in oxygen via the convection currents created and to isolate the heat source from the vapour produced.
6. - An outlet tap to allow removal of rinsing or tested liquid.
7. - A dedicated measuring cylinder marked at a 50 ml volume, for the wine's boiling point measurement, and also marked at a 20ml volume for the water's boiling point measurement at the prevailing atmospheric pressure at the time of measurement.
The accuracy of these volumes are not critical.