Honors Chemistry Lab Report
Separation of a Mystery Mixture
Date Turned In
Lab Group #X
Lab Manager: Name1
Technician: Name2
Recorder: Name3
Gopher: Name4
Purpose:
The goal of this laboratory experiment is to apply knowledge of mixture types,
physical properties, and the separation techniques. A heterogeneous mixture of
sand, salt, and metal filings is separated into its individual components using
magnetism, filtration, and evaporation. The mass of the original mixture is
compared to the sum of the mass of its individual components.
Materials & Equipment
Table 1: Materials
Mixture to be separated
Water
Table 2: Equipment
Balance Beam
3 Beakers (400 ml)
Magnet
Hot Plate
Glass Funnel
Plastic Bags
Ring Stand
Stirring Rod
Filter Paper
Clay Triangle
Beaker Tongs
Procedure:
There are four parts to this lab procedure. First, initial measurements are taken and
then three separations are performed.
I.
Determine Weight of Initial Mixture
a. Set up and zero balance beam.
b. Weigh empty beaker.
c. Add mixture.
d. Weigh beaker with mixture.
e. Calculate mixture weight.
f. Record weight and observations.
II.
Separation of Metal Filings from Mixture
a. Weigh plastic bag.
b. Weigh empty beaker for filings.
c.
d.
e.
f.
g.
h.
i.
j.
Place plastic bag on magnet.
Pull magnet through mixture several times to attract metal filings.
Carefully invert bag from magnet so all filing stay in bag.
Empty bag over beaker.
Repeat steps c through f until no filings are removed from mixture.
Weigh beaker with mixture.
Calculate mixture weight.
Record weight and observations.
III.
Separation of Sand from Mixture
a. Weigh filter paper.
b. Weigh beaker.
c. Place paper in funnel in clay triangle on ring stand.
d. Wet slightly to hold in place.
e. Add about 50 ml warm water to mixture in beaker.
f. Stir mixture to ensure salt is dissolved.
g. Let mixture settle for 2 minutes.
h. Decant the mixture through filter paper.
i. Capture salt and water in beaker under funnel.
j. Let wet sand sit in beaker on lab counter until dry.
k. Remove filter paper from funnel and let dry on counter.
l. When dry weigh beaker of sand and paper.
m. Calculate sand weight.
n. Record weight and observations.
IV.
Separation of Salt from Water
a. Plug in hot plate and set on HEAT Level 8.
b. Place beaker with salt water on hot plate.
c. Watch until water seems gone.
d. Turn hot plate off or on low.
e. Remove beaker with tongs.
f. Weigh on balance beam.
g. Put beaker back on hot plate for 1 minute.
h. Reweigh beaker.
i. Continue steps e through h until there is no change in weight.
j. Calculate salt weight.
k. Record weight and observations.
Data and Observations
The complete recorded data and observations are available in the Appendix. Tables
3 and 4 show the most relevant information.
Table 3: Experimental Results
Initial (g)
Total Mixture
Metal Filings
Sand
Salt
100.10
Unknown
Unknown
Unknown
Final (g)
96.85
0.70
58.40
37.75
Difference (g)
3.25
Unknown
Unknown
Unknown
Table 4: Observation Log
Experimental Procedure
Observation
Separating Steel Wool
1. Magnet did not pick up steel wool easily
2. Some sand got stuck within the steel wool
Adding water to the mixture
1. Not all of the salt was dissolved after mixing and
letting the mixture sit
Separating sand from mixture
1. Water dripped slowly into beaker from funnel.
2. Some water was left in the sand after pouring the
mixture through the funnel.
3. Some sand got stuck to the filter paper.
Separating salt from water
1.
2.
3.
4.
Water began to heat after two minutes
Water started to boil after 4 minutes.
Water became foggy & white after 6 minutes.
Noticeable change in the quantity of the water
after 6.5 minutes.
5. Salt popped out of the beaker after 7 minutes.
6. Some salt was lost because it popped out of the
beaker.
Repeat of separating salt from
water
1. Visible water droplets on the side of beaker.
2. Visible diminishing of droplets as beaker sits on
hot plate longer.
3. Loss of weight after repeating and after sitting
overnight.
Measuring the sand
1.
2.
3.
4.
5.
Salt was still in the beaker.
Visible amount of water still in sand.
Water removed after letting sand sit overnight.
Sand became hard as water evaporated.
Loss of weight after letting sand sit overnight.
Results and Calculations
Using the data in Table 3 and the equations below, the recovery of the materials is
calculated.
Percent Recovered (%) = Sum of Recovered Masses x 100
Initial Mass of Mixture
Composition of Recovered = Individual Recovered Component x 100
Mixture (%)
Sum of Recovered Components
where the percentages of the individual recovered components sum to 100%.
Table 5: Recovery of Materials
Total Mixture
Metal Filings
Sand
Salt
Recovered (%)
96.75
N/A
N/A
N/A
Composition of
Recovered Mixture (%)
N/A
0.72
60.30
38.98
Figure 1 shows the breakdown of the initial mixture mass in terms of the individual
recovered components and the unrecovered material. Total material sums to 100.1
grams total and recovered material sums to 96.85 grams as reported in Table 3.
Figure 1: Component Recovery (g)
Metal, 0.70
Unrecovered
Mixture, 3.25
Salt, 37.75
Sand, 58.40
Error Analysis
Errors in the experimental results can result from many sources. In this lab we
found three major sources of error. These are shown in Table 6.
Table 6: Sources of Error
Possible Source of Error
Example
Measurement
Three Beam Balance Limitations

Accuracy was limited to 0.01 but the
metal filings totaled about 0.7 which
means the measurements were accurate
to only 10%
Improper use of significant figures
Separation Technique
Magnetism to remove steel wool


Not strong enough to easily lift out all
steel wool so some was left in beaker
Some steel wool actually trapped sand
within its fibers
Evaporation of water from sand and salt

Lengthy process given allotted time
Filtration of salt and water from sand

Lengthy process given allotted time
Final Measurements were made before
samples were completely dry
Experimental Technique
Many errors occurred due to experimentalists’
lack of experience:




Not all of the salt in the sand was
dissolved during filtration step
Some salt was lost because it popped
out of the beaker when heat was not
properly controlled
Different balances were used
throughout the experiment
Water, salt, steel wool and sand were
spilled and lost during container
transfer
Error Calculation Equation:
Percent Error (%) = [Initial Mass of Mixture – Sum of Recovered Masses] x 100
Initial Mass of Mixture
Percent Error (%) = [(100.1 – 96.85)/100.1] x 100 = 3.25 %
Final calculations show that 96.75 % of the mixture was recovered which accounts
for the loss of 3.25 g during experimentation as shown in Table 3.
Discussion
In this lab, the objective was to separate a mixture of steel wool, sand, and salt into
its base components. Recently studied concepts that were applied to this lab were a
variety of different methods for separating mixtures. Because one of the main
elements present in steel wool is iron, and iron is a metal with magnetic properties,
a magnetic was capable of separating the wool from the other, non-magnetic
components, namely sand and salt. As salt is able to be dissolved into water and
sand is not, the water and salt were able to be combined into a solution and then
filtered from the sand using filter paper. Water has a much lower boiling point than
salt, so the water could be separated from the salt by evaporating it with a hot plate
while keeping the salt in a solid state. All of these physical property differences
allowed the mixture to be separated into its base components using available
separation techniques.
Conclusion
Exploiting the properties of the individual components of the heterogeneous
mixture provided, specifically, magnetism, solubility, boiling point, and particle size,
allowed the mixture to be separated into steel wool, sand, and salt through the
application of magnetic separation, filtration, and evaporation with a 96.75 %
recovery.
APPENDIX
ORIGINAL EXPERIMENTAL DATA
AND OBSERVATION LOGS
(ATTACH YOUR ORIGINAL LAB NOTES AFTER THIS PAGE)