Determining the Identity of Unknown Materials
Purpose:To identify unknown materials using density.
Materials:
Electronic Scale
Graduated Cylinders (10mL, 25mL and 100mL)
Overflow can
10 mL Unknown Liquid A
10 mL Unknown Liquid B
Unknown Solid A
Unknown Solid B
Procedure:
Identification of an Unknown Liquid
1. Record the mass of a graduated cylinder of your choice.
2. Pour approximately 10mL of the unknown liquid into the graduated
cylinder you chose to use.
3. Record the exact volume of the liquid.
4. Record the mass of the graduated cylinder with the unknown liquid
inside.
5. Subtract the mass of the cylinder from the mass of the cylinder with the
unknown liquid inside. This will will give the mass of the unknown liquid.
Identification of an Unknown Solid
1. Record the mass of the unknown object.
2. Place enough water in the overflow can to a point where the water is no
longer coming out of the spout.
3. Carefully drop the object into the overflow can. (NOTE: It must be fully
submerged, if not add more initial water.)
4. Make sure to catch any of the water coming out of the spout into a
graduated cylinder. (Measure the volume using the graduated cylinder)
5. Record this in your table.
*Calculate the density of the substances in your tables.
Observations:
Identification of Unknown Liquid
Trial
Unknown #1
Mass of
graduated
cylinder (g)
Mass of
graduated
cylinder and
unknown (g)
Mass of
unknown (g)
Exact
Volume
(mL)
Density
(g/mL)
Mass of
graduated
cylinder and
unknown (g)
Mass of
unknown (g)
Exact
Volume
(mL)
Density
(g/mL)
1
2
Unknown #2
1
2
Identification of Unknown Solid
Trial
Unknown #1
1
2
Unknown #2
1
2
Mass of
graduated
cylinder (g)