In this experiment, you will use the different physical and chemical properties of the components of a mixture of sand (SiO2), sodium chloride (NaCl), and calcium carbonate (CaCO3) to separate each of these substances from the
mixture. Some of the physical and chemical properties of these three substances are listed in Table 2.1.
Table 2.1 Selected physical and chemical properties of several compounds
Substance Soluble in H2O Reacts with 3 M HCI
SiO2
No
No
Naci
Yes
No
CaCO3
No
Yes
CaSO4
No
No
Ca(NO3)2
Yes
No
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A flow diagram is a schematic representation of a series of operations. Constructing a flow diagram as you do an
experiment is an effective way of recording your data and observations and may be helpful in this case in
summarizing the different steps you will take to accomplish the separation.
A flow diagram for this experiment should show the following steps:
extract the NaCl from the mixture with water
use gravity filtration to separate the insoluble SiO2 and CaCO3 from the aqueous solution of NaCl
recover NaCl from the filtrate by evaporating the water
react CaCO3 in the filtration residue with aqueous HCl, as shown in Eq. 2-3; SiO2 will remain as an
unreacted solid
CaCO3 (s) + 2 HCl(aq) - CaCl2 (aq) + CO2(g) + H20 (1)
Eq. 2-3
decant the supernatant liquid from the unreacted SiO2
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