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Determination of relative atomic mass

Description

In this experiment you will react magnesium ribbon with dilute hydrochoric acid to produce hydrogen gas. The measured volume of hydrogen gas produced and the mass of magnesium can be used to determine the mass of magnesium required to produce one mole of hydrogen molecules. From this you can deduce the relative atomic mass of magnesium.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
determination-of-relative...

 



Apparatus Chemicals

Eye protection

The teacher and each working group will require:

Fine emery paper, a few cm x2

Burette (50 cm3) (Note 1)

Burette stand

Funnel, small

Beaker (100 cm3)

Beaker (250 cm3)

Access to:

Top-pan balance, accurate to +/- 0.001 g (Note 2)

Room temperature and pressure measurements (Note 3)

Hydrochloric acid, 2 M, (IRRITANT), 25 cm3

Magnesium ribbon, approx 3 - 4 cm length

Refer to Health & Safety and Technical notes section below for additional information.

 


Read our standard health & safety guidance





Weblinks
Chemguide- most websites deal with instrumental procedures for determining atomic masses, such as mass spectrometry. Most of these are concerned with levels of detail far beyond what is appropriate even for more advanced students. For a fairly detailed treatment of mass spectrometry for determining atomic masses suitable for advanced students.


Page last updated October 2015

The measured volume of hydrogen gas produced and the mass of magnesium can be used to determine the mass of magnesium required to produce one mole of hydrogen molecules. From this you can deduce the relative atomic mass of magnesium.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology.