Experiment One: Techniques and Measurements
Objectives
You will be able to properly select and operate a balance and analytical glassware such as pipet,
buret and graduate cylinder. As a practice, you will be determining the density of a selected
solid and liquid.
Introduction
The use of laboratory equipment requires a knowledge and understanding of the scope of and
limits of the equipment that is being used. Thus, a large scale balance is sufficient to measure
the student, while, it is not suitable to measure the mass of gold ring. Once, the appropriate
laboratory apparatus has been selected for the experiment, the next step is to use it properly to
obtain reliable data.
The laboratory balance is perhaps the most common equipment in any laboratory. Balances are
of different sizes, ranges and sensitivities. The selection of the appropriate balance depends
upon the degree of accuracy and precision required from the analysis.
Most glassware in your laboratory has been marked by the manufacturer to indicate the volume
and accuracy. For example, beakers and Erlenmeyer flasks are marked with approximate
volumes and could not be used for accurate measurements. However, burets, pipets and
graduate cylinders are used for accurate and precise measurements.
In this experiment you will use some of the laboratory equipment to determine the density of a
liquid sample and the density of solid substance. Density is an intensive property (its value is
independent on mass or volume of substance). Its value is expressed as the ratio between mass
and volume.
Density= Mass / Volume
For most solid and liquid samples, it is reported in g/cm3. In this experiment the density of a
liquid is determined by measuring the mass of a known volume of the liquid. The density of a
water-insoluble solid is determined by measuring its mass and then the volume of water it
displaces.
Examples
Example 1: Determine the density of water.
mass graduated cylinder
mass of water
density of water
37.288 g
5.002 g
D 
mass cylinder and water
volume of water
m
5.002 g

 1.00 g/mL
V
5.00 mL
42.290 g
5.00 mL
Example 2: Determine the density of mineral.
mass graduated cylinder
mass mineral oil
density of mineral oil
37.249 g
4.471 g
D 
m
V

4.471g
5.00 mL
mass cylinder and mineral oil
volume of mineral oil
41.720 g
5.00 mL
 0.894 g/mL
Example 3: Determine the density of the sodium chloride solution.
Unknown Number 1355
mass graduated cylinder
mass salt solution
density of salt solution
37.222 g
5.233 g
D 
mass cylinder + salt solution
volume of salt solution
42.455 g
5.00 mL
5.233g
m

 1.05g/mL
V
5.00 mL
Example 4: Determination of the densities of the regularly shaped objects.
cube
dimensions
volume
mass
D 
3.65 cm per side
(3.65 cm)3 = 48.6 cm3
19.565 g
19.565g
m

 0.403g/cm 3
3
V
48.6 cm
rectangular solid
dimensions
7.52 cm  3.76 cm  1.29 cm
volume
36.5 cm3
mass
24.034 g
D 
24.034g
m

 0.658g/cm 3
3
V
36.5 cm
sphere
dimensions
15.88 circumference
circum
15.88 cm
r 

 2.527 cm
2
2(3.1416)
cylinder
dimensions 1.15 cm dia. 7.60 cm length
volume
4
V  (3.1416)(2.527 cm) 3  67.59 cm 3
3
mass
4.400 g
volume V = (3.1416)(0.575 cm)2(7.60 cm)
D 
4.400 g
m

 0.06510 g/cm 3
V
67.59 cm 3
V = 7.89 cm3
mass
D 
6.029 g
6.029g
m

 0.764g/cm 3
V
7.89 cm 3
Example 5: Determination the density of the unknown, irregularly shaped metal.
Unknown number 5000
mass of metal
volume of water
volume of water plus metal
density of metal
D 
metal identity aluminum
15.058 g
20.0 mL
26.0 mL
15.058g
m

 2.5 g/mL
V
6.0 cm 3
Experimental
Apparatus / Reagents Required
Graduated cylinder (50, 100 mL), pipet (10, 25 mL), pipet filler, sodium chloride, water-soluble
liquids, small pieces of metal materials.
Procedures
Record your data and observations directly on the data sheet. Perform at least two trials.
A. Determination of the density of pure liquid
1. Clean and wipe dry a 50-mL beaker to the nearest 0.01 g.
2. Obtain about 50 mL distilled water in a clean 100-mL Erlenmeyer flask. Measure and record
the temperature of the water.
3. obtain a 10-mL pipet and a pipet bulb. Clean the pipet with soap and water. Rinse the pipet
with tab water followed by distilled water.
4. Pipet 10.0 mL of the distilled water from the flask into the clean beaker.
5. Calculate the density of the water.
6. Obtain an unknown liquid and record its identification number.
7. Determine the density of of the unknown liquid following steps 1 to 5.
B. Density of Solutions
1. Prepare approximately 50 mL of 10 % mass/volume sodium chloride solution by dissolving
5.00 g NaCl in 50 mL distilled water.
2. Follow steps 1 to 4 in section A.
3. Calculate the density of sodium chloride solution.
C. Density of solids
1. Obtain a sample of the solid substance and record its identification number.
2. Weigh an empty 50-mL beaker to the nearest 0.01 g. Weigh about 50 g of solid material and
record the total mass to the nearest 0.01 g.
3. Add water to your 50-mL graduated cylinder to approximately the 25-mL mark. Record the
exact volume of water in the cylinder to the nearest 0.1 mL.
4. Pour the solid sample into the graduated cylinder, making sure that none of the pieces sticks
to the walls of the cylinder above the water level. Shake the cylinder gently to make certain that
no air bubbles have been trapped among the pieces of the solid.
5. Read the level of the water in the graduated cylinder to nearest 0.1 mL.
6. Calculate the density of solid substance.
Experiment One: Techniques and Measurements
Pre-Laboratory Questions
Student name:
Section:
ID:
Instructor:
Q1. A piece of metal weighing 9.48 g is added to 21.27 mL water in a graduated cylinder. The
water level rises to 24.78 mL. Calculate the density of the metal.
Q2. An empty beaker weighs 32.4257 g. A 10.00 mL sample of unknown liquid is transferred to
the beaker. The total mass of the beaker and the sample was 39.4507 g. Calculate the density of
unknown liquid.
Q3. Fill the space with higher or lower or no effect in all the following statements:
1. In section B, part of liquid was left in pipet, measured density will be ----------.
2. In section B, the level in liquid in pipet was above the mark, measured density will be ------.
3. In section B, a 20-mL pipet was used instead of 10-mL pipet, measured density will be ------.
4. In section C, part of the solid substance was above the level of water, measured density will
be ---------.
5. In section C, Air bubbles were not removed before measuring final volume, measured density
will be ------.
6. In section C, a 100-mL graduated cylinder was used instead of 50-mL graduated cylinder,
measured density will be --------.
Experiment One: Techniques and Measurements
Results and Calculations
Student name:
Section:
ID:
Instructor:
A. Determination of the density of pure liquid
Pure water
Trial 1
Mass of beaker (empty)
Mass of beaker and water
Mass of water
Volume of water
Temperature of water
Density
Average density
Unknown liquid
Trial 2
g
g
g
mL
o
C
g/mL
g
g
g
mL
o
C
g/mL
g/mL
Unknown number
Mass of beaker (empty)
Mass of beaker and liquid
Mass of liquid
Volume of liquid
Temperature of liquid
Density
Average density
g
g
g
mL
o
C
g/mL
g
g
g
mL
o
C
g/mL
g/mL
B. Density of Solutions
Solution
Mass of beaker (empty)
Mass of beaker and
solution
Mass of solution
Volume of solution
Temperature of solution
Density
Average density
Trial 1
Trial 2
g
g
g
g
g
mL
o
C
g/mL
g
mL
o
C
g/mL
g/mL
C. Density of Solids
Solid
Mass of beaker (empty)
Mass of beaker and solid
pieces
Initial water level in
graduated cylinder
Final water level in
graduated cylinder
Volume of solid particles
Temperature of water
Density
Average density
Calculations:
Conclusions
Trial 1
Trial 2
g
g
g
g
mL
mL
mL
mL
mL
o
C
g/mL
mL
o
C
g/mL
g/mL