The aim of this experiment was to see how close you could measure the density of atoms with crude experiments. The second part of the experiment dealt with Solubility of large ions and their Hydration enthalpy. Hydration enthalpy is the enthalpy change when 1 mole of an ionic substance dissolves in a solution to give a solution of infinite dilution. (Jim Clark, 2010). (Jonathan Hopton, 2011) Hydration Enthalpy decreases (gets less negative) down a group, the Solubility of the group 2 metals also decreases down the group.
The method was followed exactly like described in the practical handbook. The Mass was calculated by weighing the elements in a Weigh bucked with a mass of 1.041g. The volume was determent by adding 5 cm3 water into a measuring beaker and then adding the element and noting the water level deference. Then to get the volume you subtract the water level deference from five.
Densities for Group IV Elements
| Carbon| Silicon| Tin| Lead|
Mass /g| 0.597| 0.784| 2.535| 3.766|
Volume/cm3| 0.3| 0.4| 0.4| 0.4|
Density/g cm-3| 1.99| 1.96| 6.33| 9.415|
Reported Density/g cm-3| 2.2| 2.33| 6.99| 11.34|
% Error| 9.54%| 15.87%| 9.44%| 16.97%|
I noted that the further you move down the group on the periodic table the % error of the calculations becomes generally more.
Of the experiment demonstrates that a very useful Pease of information about the elements on the periodic table can be determent with a very easy experiment. The present error can be brought down by making sure water stays at an constant temperature, the mass is determent to greater decimal plyces, and a more accurate measuring flask.
* Hopton, J. 2011 GROUP II ELEMENTS Beryllium to Barium [Intyds]. Beskikbaar: http://www.knockhardy.org.uk/sci_htm_files/gii
[2011, August 03].
* Clark, J. 2010. ENTHALPIES OF SOLUTION AND HYDRATION [Intyds]. file:///C:/Users/Arno%20Welgemoed/Pictures/solution.html
[2011, August 03].