SOLUTION MANUAL
SOLUTION MANUAL
,Experiment 1
Basic Laboratory Operations
INTRODUCTION This is the first “experiment” that most students perform in the laboratory.
Oftentimes, the “stone is cast” in this first laboratory session. Your presentation
will determine, in large part, student expectations and goals. If you emphasize the
significance of the laboratory experience—the importance of laboratory safety, the
application of proper laboratory techniques, and a thought process that includes the
application of basic chemical principles—you will have a well-run lab.
In our laboratories, we stress the importance of practicing good laboratory technique.
At the conclusion of the Laboratory Techniques section in the laboratory manual,
there is a Laboratory Technique Assignment (pages 35-36). Assign this as an in-lab
or take-home assignment for students to become familiar with this section of the
manual.
Work Arrangement: Individuals. Divide the students into two groups:
Group I: Begin Part A
Group II: Begin Part B.
Time Requirement: 2.5 hours
LECTURE OUTLINE 1. Follow the Instruction Routine outlined in “To the Laboratory Instructor”.
2. Note for students that circled superscripts in the Experimental Procedure are
stopping points at which students are to make an entry on the Report Sheet.
3. Part A. Cite the various parts of a Bunsen burner and the zones of a properly
adjusted (nonluminous) Bunsen flame.
Demonstrate, with an explanation, the lighting of a Bunsen burner
(Experimental Procedure, Part A.1). This very important technique is not in the
Laboratory Techniques section of the laboratory manual.
4. Part B. Discuss the proper use and care of balances (Technique 6). Balances are
used extensively in this course and students must learn to handle them with
respect.
5. Part B.2. Repetitious mass and volume measurements show the random errors
in making measurements in the laboratory and the importance of recording data
with the correct number of significant figures…according to the precision of the
instrument (balance and graduated cylinder). Refer to the Laboratory Data
section of the laboratory manual for significant figures and how they are to be
recorded.
6. Part C. Define density. Density is an intensive and physical property of matter.
Describe the procedure for the density measurement of a water-insoluble solid
and a liquid.
7. Part C.2. Class or group data are requested for completing the density data for
water on the Report Sheet. Inform students how these data are to be collected.
You may choose to have students calculate the standard deviation for the group
data (see Data Analysis section of the laboratory manual).
The Next Step. Have students devise a procedure for measuring the density of a
water-insoluble solid that is less dense than water or the density of a water-soluble
6 Basic Laboratory Operations
,solid. Extra credit?
• Part A. Where there is fire, there is danger. CAUTIONS
Part A. Use tongs or forceps for holding the wire gauze in the flame. & DISPOSAL
Part C.1. Return the unknown solids for use in other laboratories.
Part C.2. Do not pipet by mouth.
Part C.2. Caution the students of handling potentially flammable liquids near a
Bunsen flame. Dispose of the liquid unknowns in the “Waste Liquids”
container.
1. Part A. All Bunsen burners are not the same; for example, some do not have a
TEACHING HINTS
gas control valve. Advise students to adjust the Experimental Procedure
accordingly.
Assist students in the lighting and adjusting of the Bunsen burner. Make sure
the tubing is attached to the gas outlet, not the water outlet! Remove combustible
substances from the area near the Bunsen burner. Extinguish the Bunsen flame
when it is not in use.
2. Part B. Over-emphasize, if necessary, the care and operation of balances.
Students seem not to appreciate the delicacy (and the sensitivity) of a balance (for
some reason). Oversee its operation at all times. Keep the balance area clean of
all chemicals and glassware. Have students review Technique 6.
3. Part C.1a. Do students know the meaning of “tare the mass of a piece of
weighing paper?” It can only be done with a balance having that feature.
4. Part C.1c. Roll the metal in the water to remove air bubbles. Watch that students
properly read and record a meniscus (see Technique 16A).
5. Part C.2. Supervise the use of the pipet and the proper pipetting technique
(Technique 16B)—students are not to pipet with their mouths. (Caution: keep
liquid unknowns away from the Bunsen flame.)
Issue a solid sample for Part C.1 and a liquid sample for Part C.3. Provide labeled
SUGGESTED
containers for the return of the solid samples and a “Waste Liquids” container
for the liquid samples.
UNKNOWNS
Part C.1 Density Part C.3 Density
Solida (g/cm3) Liquida (g/mL)
aluminum 2.70 methanol 0.791
copper 8.95 ethanol 0.789
iron (nails, not water 1.00
galvanized) 7.86 1-propanol 0.804
lead 11.34 toluene 0.867
nickel 8.90
silicon 2.42
tin 7.28
zinc 7.14
aVolumes of 3–5 cm3 of metal and 10 mL of liquid are needed.
Bunsen burner 1 balance, ±0.01 g 1
SPECIAL
match or striker 1 balance, ±0.001 g 1
EQUIPMENT
Experiment 1 7
, wire gauze
crucible tongs
graduated cylinder, 10 mL 1
“Waste Liquids” container
5-mL pipet and bulb 1
weighing paper
PRELABORATORY 1. Methane, commonly known as natural gas, is the common fuel and the oxygen is
ASSIGNMENT the required air component for producing an efficient, nonluminous Bunsen
flame.
2. a. Blue. A nonluminous flame is a blue flame that indicates the fuel is
undergoing complete combustion.
b. Less. A luminous flame contains carbon particles that have not undergone
combustion and therefore burns less efficiently, producing a lower
temperature flame.
3. See Figures T.16a and T.16b, page 35.
4. [Depends upon the laboratory, most likely ±0.01 g or ±0.001 g]
5. Flames from a wood-burning fireplace are typically yellow in appearance
because of an insufficient amount of oxygen near the burning wood producing a
luminous flame. The yellow appearance of the luminous glow is due to the
presence of the unburned carbon particles.
6. a. …touching the tip to the wall of the receiving vessel
b. …forefinger or index finger (not the thumb!)
c. The last bit of liquid remaining in the pipet after delivery should remain in
the pipet.
d. TD means “to deliver”…the pipet is calibrated to deliver the volume for
the calibrated pipet, allowing the liquid to flow from the pipet with only the aid
of gravity.
7. The cylinder containing the diamond. Platinum is more dense than diamond;
therefore an equal mass of diamond would displace a larger volume of water.
cm3
For example, 21.43 g of diamond displaces a volume of (21.43 g x 3.51 g = )
6.11 cm3, while 21.43 g of platinum displaces only 1 cm3 of water.
8. mass of “conc” hydrochloric acid = (11.229 – 5.333) g = 5.896 g
5.896 g
density = 5.00 mL = 1.18 g/mL
1. When the gas control valve is slightly closed on a nonluminous flame, less fuel is
LABORATORY
available for the combustion of the fuel, reducing the “size” of the flame but
QUESTIONS still producing a nonluminous flame.
2. When the air control valve is slightly closed on a nonluminous flame, less air is
available for the combustion of the fuel, producing a luminous flame.
3. The fuel for the burning candle is the candle wax. The flame is luminous because
the oxygen supply at the base of the wick is insufficient to combust all of the
burning candle wax.
4. Higher density. If the solid is not submerged, less water is displaced resulting in a
smaller measured volume of the solid. A smaller volume with a given mass
results in a greater reported density.
8 Basic Laboratory Operations
SOLUTION MANUAL
,Experiment 1
Basic Laboratory Operations
INTRODUCTION This is the first “experiment” that most students perform in the laboratory.
Oftentimes, the “stone is cast” in this first laboratory session. Your presentation
will determine, in large part, student expectations and goals. If you emphasize the
significance of the laboratory experience—the importance of laboratory safety, the
application of proper laboratory techniques, and a thought process that includes the
application of basic chemical principles—you will have a well-run lab.
In our laboratories, we stress the importance of practicing good laboratory technique.
At the conclusion of the Laboratory Techniques section in the laboratory manual,
there is a Laboratory Technique Assignment (pages 35-36). Assign this as an in-lab
or take-home assignment for students to become familiar with this section of the
manual.
Work Arrangement: Individuals. Divide the students into two groups:
Group I: Begin Part A
Group II: Begin Part B.
Time Requirement: 2.5 hours
LECTURE OUTLINE 1. Follow the Instruction Routine outlined in “To the Laboratory Instructor”.
2. Note for students that circled superscripts in the Experimental Procedure are
stopping points at which students are to make an entry on the Report Sheet.
3. Part A. Cite the various parts of a Bunsen burner and the zones of a properly
adjusted (nonluminous) Bunsen flame.
Demonstrate, with an explanation, the lighting of a Bunsen burner
(Experimental Procedure, Part A.1). This very important technique is not in the
Laboratory Techniques section of the laboratory manual.
4. Part B. Discuss the proper use and care of balances (Technique 6). Balances are
used extensively in this course and students must learn to handle them with
respect.
5. Part B.2. Repetitious mass and volume measurements show the random errors
in making measurements in the laboratory and the importance of recording data
with the correct number of significant figures…according to the precision of the
instrument (balance and graduated cylinder). Refer to the Laboratory Data
section of the laboratory manual for significant figures and how they are to be
recorded.
6. Part C. Define density. Density is an intensive and physical property of matter.
Describe the procedure for the density measurement of a water-insoluble solid
and a liquid.
7. Part C.2. Class or group data are requested for completing the density data for
water on the Report Sheet. Inform students how these data are to be collected.
You may choose to have students calculate the standard deviation for the group
data (see Data Analysis section of the laboratory manual).
The Next Step. Have students devise a procedure for measuring the density of a
water-insoluble solid that is less dense than water or the density of a water-soluble
6 Basic Laboratory Operations
,solid. Extra credit?
• Part A. Where there is fire, there is danger. CAUTIONS
Part A. Use tongs or forceps for holding the wire gauze in the flame. & DISPOSAL
Part C.1. Return the unknown solids for use in other laboratories.
Part C.2. Do not pipet by mouth.
Part C.2. Caution the students of handling potentially flammable liquids near a
Bunsen flame. Dispose of the liquid unknowns in the “Waste Liquids”
container.
1. Part A. All Bunsen burners are not the same; for example, some do not have a
TEACHING HINTS
gas control valve. Advise students to adjust the Experimental Procedure
accordingly.
Assist students in the lighting and adjusting of the Bunsen burner. Make sure
the tubing is attached to the gas outlet, not the water outlet! Remove combustible
substances from the area near the Bunsen burner. Extinguish the Bunsen flame
when it is not in use.
2. Part B. Over-emphasize, if necessary, the care and operation of balances.
Students seem not to appreciate the delicacy (and the sensitivity) of a balance (for
some reason). Oversee its operation at all times. Keep the balance area clean of
all chemicals and glassware. Have students review Technique 6.
3. Part C.1a. Do students know the meaning of “tare the mass of a piece of
weighing paper?” It can only be done with a balance having that feature.
4. Part C.1c. Roll the metal in the water to remove air bubbles. Watch that students
properly read and record a meniscus (see Technique 16A).
5. Part C.2. Supervise the use of the pipet and the proper pipetting technique
(Technique 16B)—students are not to pipet with their mouths. (Caution: keep
liquid unknowns away from the Bunsen flame.)
Issue a solid sample for Part C.1 and a liquid sample for Part C.3. Provide labeled
SUGGESTED
containers for the return of the solid samples and a “Waste Liquids” container
for the liquid samples.
UNKNOWNS
Part C.1 Density Part C.3 Density
Solida (g/cm3) Liquida (g/mL)
aluminum 2.70 methanol 0.791
copper 8.95 ethanol 0.789
iron (nails, not water 1.00
galvanized) 7.86 1-propanol 0.804
lead 11.34 toluene 0.867
nickel 8.90
silicon 2.42
tin 7.28
zinc 7.14
aVolumes of 3–5 cm3 of metal and 10 mL of liquid are needed.
Bunsen burner 1 balance, ±0.01 g 1
SPECIAL
match or striker 1 balance, ±0.001 g 1
EQUIPMENT
Experiment 1 7
, wire gauze
crucible tongs
graduated cylinder, 10 mL 1
“Waste Liquids” container
5-mL pipet and bulb 1
weighing paper
PRELABORATORY 1. Methane, commonly known as natural gas, is the common fuel and the oxygen is
ASSIGNMENT the required air component for producing an efficient, nonluminous Bunsen
flame.
2. a. Blue. A nonluminous flame is a blue flame that indicates the fuel is
undergoing complete combustion.
b. Less. A luminous flame contains carbon particles that have not undergone
combustion and therefore burns less efficiently, producing a lower
temperature flame.
3. See Figures T.16a and T.16b, page 35.
4. [Depends upon the laboratory, most likely ±0.01 g or ±0.001 g]
5. Flames from a wood-burning fireplace are typically yellow in appearance
because of an insufficient amount of oxygen near the burning wood producing a
luminous flame. The yellow appearance of the luminous glow is due to the
presence of the unburned carbon particles.
6. a. …touching the tip to the wall of the receiving vessel
b. …forefinger or index finger (not the thumb!)
c. The last bit of liquid remaining in the pipet after delivery should remain in
the pipet.
d. TD means “to deliver”…the pipet is calibrated to deliver the volume for
the calibrated pipet, allowing the liquid to flow from the pipet with only the aid
of gravity.
7. The cylinder containing the diamond. Platinum is more dense than diamond;
therefore an equal mass of diamond would displace a larger volume of water.
cm3
For example, 21.43 g of diamond displaces a volume of (21.43 g x 3.51 g = )
6.11 cm3, while 21.43 g of platinum displaces only 1 cm3 of water.
8. mass of “conc” hydrochloric acid = (11.229 – 5.333) g = 5.896 g
5.896 g
density = 5.00 mL = 1.18 g/mL
1. When the gas control valve is slightly closed on a nonluminous flame, less fuel is
LABORATORY
available for the combustion of the fuel, reducing the “size” of the flame but
QUESTIONS still producing a nonluminous flame.
2. When the air control valve is slightly closed on a nonluminous flame, less air is
available for the combustion of the fuel, producing a luminous flame.
3. The fuel for the burning candle is the candle wax. The flame is luminous because
the oxygen supply at the base of the wick is insufficient to combust all of the
burning candle wax.
4. Higher density. If the solid is not submerged, less water is displaced resulting in a
smaller measured volume of the solid. A smaller volume with a given mass
results in a greater reported density.
8 Basic Laboratory Operations
