A Qualitative Analysis: Determining Densities of Unknown Metals
Name: _________________________________ Partner’s Name: _____________________________
Date: __________________________________ Block / Period: ______________________________
Background / Introduction:
Different materials can be distinguished from one another because they have different chemical and
physical properties. One property that is often used to identify unknown materials is density. Density
is defined as the ratio of a material’s mass to its volume (or the amount of matter in a given space).
By measuring the mass and volume of a sample of material you can obtain an important clue about the
identity of the material.
Purpose:
Can you qualitatively identify unknown metals by calculating their density and pairing this
information with any additional physical properties?
Objectives:
 Measure the mass and volume of four metal samples
 Calculate the density of each sample from these measurements.
 Compare the calculated densities with known densities of specific metals.
 Identify each metal sample, using the calculated densities, color, texture, etc.
Materials:
 4 metals samples A – D
 Balance


50- ml graduated cylinder
Water, Paper towels
Prelab questions:
1. What is the formula to calculate density?
2. What are the units for density?
3. A sample of metal has a mass of 85.6 g and a volume of
12.1 ml. What is the density of metal X?
4. A metal bar has a density of 19.3 g/ml and a mass of 50.0 g.
What is the volume of the bar?
Procedure:
1. Select one of the four provided metal samples, RECORD all visible observations.
2. Determine the mass of the selected metal sample to the nearest whole value with one
additional estimated decimal. Record the masses in the data table.
3. Fill the graduated cylinder half full of water. Record the volume.
A Qualitative Analysis: Determining Densities of Unknown Metals
4. Tilt the graduated cylinder and CAREFULLY drop in the metal sample without breaking the
glass or splashing any water out. Record the NEW volume of the water plus metal sample.
5. Repeat for each of the four metal samples. Cleanup: (dry the samples and return to your
bag).
Data and Observations:
Data Table
Sample
(Observations / Description)
Volume of
water (ml)
Mass (g)
Volume of
water +
sample (ml)
Volume of
sample (ml)
Density (g/ml)
Post Lab
1. Calculate the density of each metal sample? (BE SURE TO SHOW ALL WORK)
Metal 1
Metal 2
Metal 3
Metal 4
2. What is the possible identity of each sample? If you are unable to positively identify a metal
using the density alone, check out and compare additional characterizes (color, hardness,
texture, etc.)
Metal 1
Metal 2
Metal 3
Possible
Identification
3. How would the presence of bubbles in the graduated cylinder affect your results?
4. List some possible sources of error for this lab.
5. Write two things you learned in this lab. For full credit, be thorough and explicit.
Metal 4
A Qualitative Analysis: Determining Densities of Unknown Metals
**Note that the density of metals actually varies somewhat
depending on how the metal is produced. Not only this, but you
may also experience some ERROR in lab which will produce slightly
different values. Your measured value may thus be different
from the value listed above, but it may still be correct**
Densities of selected metals
Metal
Aluminum
Chromium
Copper
Gold
Iron (steel)
Lead
Magnesium
Mercury
Nickel
Brass
Potassium
Silver
Tin
zinc
Density (g/cm3)
2.699
7.13
8.89
19.33
7.86
11.347
1.738
13.596
8.85
8.43
0.87
10.6
7.184
7.19