CHEM 111G – General Chemistry I
Lab 1 Separation of the components of a mixture
Aim of the experiment:
To develop a stepwise procedure to separate the four components of a mixture of sand, salt, iodine and iron filings and determine the % of each by mass
Brief procedure:
The stepwise procedure was developed based on unique properties of each component: Salt: soluble in water
Sand: insoluble in water
Iodine: sublimes to vapor
Iron: attracted to magnet
We weighed out ~2g of the mixture in a 250mL beaker and chose to separate the iron first using a magnet. Since the iron sticks strongly to the magnet, the beaker + mixture was then reweighed to determine the mass of iron removed by difference.
The iodine was then removed in the next step by placing the beaker on a hot plate covered by an ice cold evaporating dish and heating at maximum heat until no more purple iodine vapor were seen coming off. The deposited iodine crystals were recovered from the underside of the dish. Because some iodine is lost the beaker + mixture was then reweighed to determine the mass of iodine removed by difference.
The remaining mixture of sand and salt was treated with deionized water to extract the salt (soluble). The sand was removed by filtration through a filter funnel via the water vacuum pump and the filtrate transferred to another weighed beaker. The salt was then recovered by evaporating the filtrate to dryness. The beaker was cooled and the salt mass determined by mass difference.
The mass of sand was determined by:
Mass of sand = Mass of mixture used – mass of iron – mass of iodine – mass of salt.

The calculations are shown in the table below:
Component
iron iodine salt sand TOTAL

Mass
0.5
0.32
0.49
0.56 by difference
1.92

% mass
28.15
16.67
25.52
29.17

actual
10%
10%
40%
40%

What was learnt:
In a mixture, the components