LABORATORY EXPERIMENT #1
DENSITY MEASUREMENTS
Objectives
1. To determine the density of the following: water, an unknown liquid, glass bead(s), and an unknown
rectangular solid.
2. To calculate the mass of glass beads from its calculated density and volume measurements. To calculate the
mass percent error.
3. To gain experience in performing the following experimental procedures: weighing by difference,
accurately measuring volume, determining volume by water displacement, basic graphing techniques, and
recognizing the use of correct number of significant digits.
Discussion
Density is a physical property of matter that is defined as the amount of mass per unit volume. The equation for
density is,
Density (d ) 
mass (m)
volume (v)
labels :
g
cm3
or
g
mL
Note the units that density is expressed, units of mass, usually grams, over units of volume, usually mL. The
label mL usually indicates the substance is in liquid form or
the label cm3 usually indicates the substance is in solid form.
To determine density: Measure the mass using a balance (be sure to note the number of decimal places
displayed on the balance). The volume can be measured directly for a liquid and for a solid by calculation or by
an indirect method, measuring the amount of water it displaces, (note the calibration units of the glassware). In
most cases, density is expressed in grams per milliliter, mL, or cm3. By definition, 1 mL = 1 cm3, the value for
density of a liquid or solid can be expressed as either g/mL or g/cm3. Also, keep in mind that Specific Gravity
is the same as Density but without any labels: just a number.
The density of common liquids and solids can be found in most chemistry handbooks. You can be given an
unknown liquid or solid, measure its mass and volume, calculate its density, and with other observable physical
properties, such as state, color, smell, determine its identity. Look up the element and the organic liquid,
ethanol(ethyl alcohol), in the Handbook of Chemistry and Physics. Complete the table next page.
Physical Properties
Lead
Ethanol
Density
___________
_____________
State (g,l,s)
___________
_____________
Color
___________
_____________
After performing the experimental techniques in this lab, you will be able to come close to identifying relatively
pure unknown solids and liquids.
Table 1
Properties of Unknown Liquids
Density
g/ml
Color
Smell
Ethanol
0.789
clear
alcohol, medicinal
25% Magnesium
Chloride Solution
0.123
clear
no odor
1.11
clear
no odor
1.00
clear
Ethylene glycol
(antifreeze)
Water
no odor
Table 2
Properties of Unknown Solids
Density
g/cm3
Color
Appearance
(sugar)
1.59
white
crystalline solid
Glass
(borosilicate)
2.40
clear
smooth solid
Copper
8.94
orange
metallic
Aluminum
2.70
shinny
smooth solid
Acrylic
1.18
clear
smooth solid
Nylon
1.22
white
smooth solid
Steel, Iron
7.87
shinny
smooth solid
PVC
1.62
Dark
grey
smooth solid
Sucrose
Procedure
A. Density of Water
1. Weigh a 125 mL Erlenmeyer flask. Record the initial mass (empty flask) with the appropriate number of
decimal places on the data sheet. Obtain a new initial mass when you begin your Run 2.
2. Measure between 15.0 mL to 25.0 mL of water in a 50 mL graduated cylinder. Measure very accurately,
record the actual volume used to the appropriate number of decimal places on the data sheet.
3. Pour the contents into the weighed Erlenmeyer flask. Reweigh the flask.
Record the final mass (flask + water) on the data sheet.
4. Subtract the initial weight from the final weight to determine the mass of the
water used and record on the data sheet.
5. Determine the density of the water by dividing the mass by the volume. The density of water is
1.000 g/mL. Your result should be within 0.05 g/mL. Record your density value on the data sheet.
Repeat the same procedures, filling in the data in Run 2 column.
Be very accurate with the volume measurement and recording weight precisely.
7. Average the two (2) density values. Report the density on the data sheet with proper significant figures.
B. Density of an Unknown Liquid
1. Obtain about 15 mL of an unknown liquid and place in a container.
Record the unknown number on the data sheet.
2. Weigh a 125 mL Erlenmeyer flask. Record the initial mass with the appropriate
number of decimal places on the data sheet.
3. Accurately measure, as close as possible, 10.0 mL of the liquid using a graduated cylinder.
Record the actual volume of liquid used with the appropriate number of digits on the data sheet.
Pour the contents from the cylinder into the weighed flask.
4. Reweigh the flask. Record the final mass on the data sheet.
5. Subtract the initial weight (empty flask) from the final weight to determine the mass of the unknown
liquid used and record on the data sheet.
6. Calculate the density of the unknown by dividing the mass by the volume.
Record the density value on the data sheet.
7. Repeat the procedure for Run 2; record the data in the column for Run 2.
8. Calculate the density of your unknown liquid from both Runs. Average the two
results. Be careful to report density with proper significant figures.
9. Refer to Tables 1 to identify your unknown and record on the data sheet.
C. Density and Mass Calculations of Glass Bead(s)
Graphing Exercise Using Glass Beads
1. Obtain and weigh 20 glass beads, record the mass on the data sheet. Pick out a
single bead, weigh this bead, and record its mass on the data sheet.
2. Obtain a 10.00 mL graduated cylinder. Fill the cylinder between 5.00 to 6.00 mL of water. Observe
the bottom of the meniscus and estimate the water level. Be sure to use the appropriate number of
significant digits (2 dec.mal places) from the graduated cylinder. Record this value (Water Level) in
the data chart corresponding to “zero” beads.
3. Place the glass bead you weighed into the graduated cylinder. Carefully observe and estimate the water
level. Record the water level value in the data chart corresponding to one (1) bead.
4. Now, place a second bead in the cylinder. Observe and record the water level in the chart corresponding
to 2 beads.
5. Now place 3 more beads (total 5 beads) into the cylinder. Observe and record the water level in the chart
corresponding to 5 beads. Repeat this procedure for each total count of beads as indicated on the data
chart: 9 total beads, 15 total beads, and 20 total beads.
6. Calculate Density, subtract Water Level (1 bead) from Water Level (0 beads).The difference between
these two values is the amount of water that was displaced by the glass bead, or in other words, is the
volume of the glass bead itself. Record this value. Repeat this procedure for 20 glass beads.
7. Calculate the density of glass beads by dividing the mass by the volume.
Record the density value on the data sheet.
density glass bead = mass of bead (g) / volume of water displaced (mL)
8. Prepare the graph: horizontal (X-axis) label Number of Beads
vertical (Y-axis) label Water Level
Calibrate the Y-axis, the first line, mark as 5.0 mL. Mark each line in
0.5 increments. The top line on the Y-axis will represent 10.0 mL.
9. Plot the data points on the graph and draw a straight line that best represents the data.
D. Density Unknown Solid – part 1
Finding Percent Error in Calculations – part 2
Part 1
1. Obtain an unknown solid and record the unknown number on the data sheet.
2. Weigh the unknown solid. Record the mass on the data sheet.
3. Measure the length, width, and thickness in cm. Remember to include the estimated digit. Record the
measurements on the data sheet.
4.
Calculate the volume of the solid.
Volume (cm3) = length x width x thickness
5. Calculate the density of the solid.
6. Average your two Density values. Refer to Table 2. Identify and record your
unknown solid.
Part 2
Now, you will calculate the Percent Error for your unknown solid.
The formula for Percent Error is below.
Equation : Percent Error =
average density of unknown - density from table 2
density ta ble 2
100
1. Refer to Table 2. Find the density of the unknown you have identified. Place this value in the
denominator in the equation above.
2. Place the average density you calculated for your unkown in the numerator. Calculate and record
Percent Error on the data table.
E. Calculating Volume & Thickness of Foil
1. Obtain a piece of foil. Record the type of foil you used: copper or aluminum
2. Weigh the foil and record the mass on the data sheet.
3. Measure the length and width of the foil, in cm, record on the data sheet.
4. Calculate the volume of foil
Remember: density = mass/volume. Refer to table 2 to find the density for the
type of foil you are using.
mass foil
Therefore, Volume foil 
density foil
5. Calculate the thickness of foil
We now have a value for volume.
Volume = length x width x thickness
We have already measured length and width, so plug in the numbers to determine
thickness. Report the number in proper significant figures on the data sheet.
Thickness (cm) 
Volume (cm3 )
length x w idth (cm 2 )
Name_______________________________ Chem. 161 Fall ’13
Lab #1
Score: ____
Data Sheet
A. Density of Water
Run 1
Run 2
mass of flask + water _______________grams
_________________grams
(final)
(final)
mass of empty flask ________________grams
_________________grams
(intial)
(intial)
mass of water _____________________grams
_________________grams
volume of water ____________________mL
_________________mL
Show your calculations for density of water for Run 1 & Run 2.
Density of water ________________g/mL
Average Density of water
__________________g/mL
________________g/mL
B. Density of Unknown Liquid
Unknown number_____
Run 1
mass of flask + liquid _______________grams
(final)
mass of empty flask ________________grams
(intial)
Run 2
___________________grams
(final)
___________________grams
(intial)
mass of unknown liquid _____________grams
___________________grams
volume of unknown liquid ___________mL
___________________mL
Show your calculations for density of unknown liquid, Run 1 & Run 2.
Record answers at the top of the next page.
Density of unknown liquid ______________g/mL
___________________g/mL
Average density of unknown liquid _________________g/mL
Identity of unknown liquid__________________________________
C.
Glass Bead(s)
use 10.00-mL graduated cylinder to recorder water level to 2 decimal places
mass 1 glass bead ____________grams
__________grams
10.00
Volume (mL)
Number Water
of Beads Level
0
1
2
5
9
14
20
mass 20 glass beads
5.00
0
5
10
15
Number of Beads
20
Show your calculations for density for 1 glass bead and 20 glass beads
Water level 1 beads ___________ mL
Water level 20 beads __________ mL
Water level 0 bead ____________ mL
Water level 0 bead ___________ mL
Volume of 1 bead ____________ mL
Volume of 20 beads __________ mL
Density of 1 bead _____________g/mL
Density of 20 beads ____________g/mL
D. Calculation for Unknown Solid
Unknown Number: _____
mass of solid ______________grams
length of solid _______________ cm
width of solid ______________cm
thickness of solid_____________cm
Show your calculations for the volume of the solid
Volume of solid ___________________ cm3
Show your calculations for density of the solid
Density of the solid __________ g/cm3
Calculations for Percent Error
Percent Error: _______________
Identity of unknown solid_______________
E. Calculation for Metallic Foil
Type of foil: _________
mass of foil _____________________grams
length of foil _______________ cm
width of foil ________________ cm
Show your calculations for volume of foil.
Volume of foil _____________________________ cm3
Show your calculations for thickness of foil
Thickness of foil ___________________cm
Conclusion
1. The mass values obtained from the balance you record, will have _____ decimal places.
2. The 10-mL graduated cylinder can be estimated and recorded with _____ decimal places,
and the 25, 50 or 100-mL cylinders will have _____ decimal places.
3. The measured lengths you obtain from the scale (ruler) will be estimated and recorded with ____
decimal places.
ADDITIONAL PROBLEMS
PART I. Conversions Problems. Be sure to show your steps for full credit.
1. 50 cm to ____________ mm
2. 25 mg to ____________ cg
3. 89 cg to ___________ g
5. 3.88*104 km to _______________ cm
4. 0.0489 L to ____________ mL
-16
8. 3.4 *10 kL to _____________ L
PART II. Carry out each of the indicated operations, round to 4 significant figures and write your answers in
proper scientific notation form
1.
75,000 * 800,000 * 0.000000045
=
66,500 * 85,000
2.
0.0045 * 78,000 *132,000,000,000
=
0.000555 * 0.00155 * 82,500,000
PART III. Density problems
1. The density of sulfuric acid is 1.894 g/cm3. What is the mass of 75.0 mL of sulfuric acid?
2. The density of alcohol is 0.78945 g/cm3. What volume would be required to obtain 100.0 g of alcohol?
3. What volume would be occupied if air has a density of 1.19 g/L and a mass of 362.3 grams?