general chemistry 8th edition solution manual and general chemistry complete solutions manual principles and modern applications
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CHE 1401
School of Science & Engineering
School of Science & Engineering
L LA AB BO OR RA AT TO OR RY Y M MA AN NU UA AL L F FO OR R
GENERAL CHEMISTRY I
GENERAL CHEMISTRY I
Last Update: 7 July 2015
Last update: July 2015 1 CHE 1401
To the Student
You are about to engage in what for most of you will be a unique experience. You are
going to collect experimental data on your own and use your reasoning powers to
draw logical conclusions about the meaning of these data. Your laboratory periods are
short, and in most instances, there will not be enough time to come to the laboratory
unaware of what you are to do, collect your experimental data, make conclusions
and/or calculations regarding them, clean up, and hand in your results. Thus, you
should read the experimental procedure in advance so that you can work in the lab
most efficiently.
After you’ve read through the experiment, try to answer the review questions we’ve
included at the end of each experiment. These questions will help you to understand
the experiment in advance.
Some of your experiments will also contain an element of danger. For this and other
reasons, your lab instructor is present to assist you. He is your friend. Treat him well
and above all don’t be afraid to ask him questions. Within reason, he will be glad to
help you.
Chemistry is an experimental science. The knowledge that has been accumulated
through previous experiments provides the basis for today’s chemistry courses. The
information now being gathered will form the basis of future courses. There are
basically two types of experiments that chemists conduct:
1 Qualitative – to determine the nature of processes, which are often
unanticipated and sometimes unpredictable.
2 Quantitative- to determine the amount of a measurable change in mass,
volume, or temperature, for example, including the time rate of change on
processes for which the qualitative data are already known.
It is much easier to appreciate and comprehend the science of Chemistry, if you
actually participate in experimentation. Although there are many descriptions of the
scientific method, the reasoning process involved is difficult to appreciate without
performing experiments. Invariably there are experimental difficulties encountered in
the laboratory that require care and patience to overcome. There are four objectives
for you, the student, in the laboratory:
1 To develop the skills necessary to obtain and evaluate a reliable original result.
2 To record your results for future use.
3 To be able to draw conclusions regarding your results (with the aid of some
coaching and reading in the beginning).
4 To learn to communicate your results critically and knowledgeably.
By attentively reading over the experiments in advance, and by carefully following
directions and working safely in the laboratory, you will be able to accomplish all
these objectives.
Best wishes for an error-free and accident-free term
Lab Manual iii CHE 1401
SAFETY IN THE LABORATORY
Safety in the laboratory must be emphasized. The compounds you will work with do have
some hazards associated with them. Therefore, it is important to follow the safety rules
outlined in this lab manual. You should assume that all compounds encountered in the
laboratory are toxic and handle them accordingly. Safety goggles for eye protection are
recommended and lab coats are to be worn by all students at all times when entering the
laboratory. Many chemicals, common in chemical laboratories, will make holes in clothing.
Always wash your hands thoroughly when leaving the laboratory. The location and use of the
safety equipment in laboratory were already discussed in CHE1401 and will be reminded by
your instructor the first day the laboratory class meets. You should become familiar with the
proper use of the safety shower, eye-wash fountain, fire blanket and fire extinguisher.
Report any accidents which occur immediately to the laboratory supervisor.
Safety rules to be strictly followed by all students:
1. Wear goggles when required.
2. Do not touch chemicals with your hands. Spatulas will be provided for handling solid
materials.
3. Do not eat or drink in the laboratory.
4. Do not taste any chemical.
5. Do not smell any chemicals directly. Use your fingers to waft the odor to your nose.
6. Do not pipet solutions by mouth. Rubber pipet bulbs are provided at each lab station.
7. Do not put flammable liquids near an open flame.
8. When heating a test tube, make certain that the open end of the tube is directed away from
the students.
9. When finished with your Bunsen Burner for a given portion of an experiment, turn it off.
10. Do not sit on the lab benches.
11. Do not engage in games in the laboratory. Failure to follow this rule will result in
immediate dismissal from the lab and subsequent conduct action.
12. Do not pour any chemicals into a sink without authorization from the instructor.
13. Notify your instructor if a mercury spill should occur.
14. All broken glassware should be cleaned up immediately. The instructor should be notified
of all breakage, especially if a thermometer is involved.
15. Do all reactions involving malodorous, noxious or dangerous chemicals in a fume hood.
16. If a chemical gets on your skin, immediately wash the affected area with large quantities
of water. The instructor should be notified; no matter how insignificant the incident might
seem.
17. When pouring one liquid into another, do so slowly and cautiously. To dilute an acid,
pour the acid into the water; never pour water into an acid.
18. No student shall be permitted to work alone in the lab, you should be supervised by a
laboratory instructor (or the lab technician during make up sessions).
19. Exercise good housekeeping practices in the laboratory. Be sure that the lab benches
remain free of disorder during the experiment. In the event of a spill, clean the area
immediately and be sure to use a wet sponge to wipe off the work station at the end of the
lab session.
20. Know what you have to do before entering the lab. Read the experiment carefully before
coming to the laboratory.
For more information, a booklet titled “Student’s Chemistry Laboratory Safety Manual”
will be provided to you in your first lab session. Please get acquainted with it.
Be cautious and think about what you are doing
Lab Manual iv CHE 1401
Safety rules
The laboratory can be but is not necessarily a dangerous place. When intelligent
precautions and a proper understanding of techniques are employed, the laboratory is
no more dangerous than any other classroom. Most of the precautions are just
common-sense practices. These include the following:
1. Wear approved eye protection when required while in the laboratory. Your safety
eye protection may be slightly different from that shown, but it must include
shatterproof lenses and side shields to provide protection from splashes.
Typical eyewash Approved eye protections
The laboratory has an eyewash fountain available for your use. In the event that a
chemical splashes near your eyes, you should use the fountain BEFORE THE
MATERIAL RUNS BEHIND YOUR EYEGLASSES AND INTO YOUR EYES.
The eyewash has a "panic bar," which enables its easy activation in an emergency.
2. Eating, drinking, and smoking are strictly prohibited in the laboratory at all times
3. Know where to find and how to use safety and first-aid equipment.
4. Consider all chemicals to be hazardous unless you are instructed otherwise.
Dispose of chemicals as instructed by your instructor. Follow the explicit
instructions given in the experiments.
5 If chemicals come into contact with your skin or eyes, wash immediately with
copious amounts of water and then consult your laboratory instructor.
6. Wear shoes at all times. “Baboosh” shoes are not allowed in the laboratory.
Lab Manual v CHE 1401
6 Never taste anything. Never directly smell the source of any vapor or gas; instead,
by means of your cupped hand, bring a small sample to your nose (see figure
below). Chemicals are not to be used to obtain a "high" or clear your sinuses.
Wafting vapors towards one’s nose
8. Perform in the hood any reactions involving skin-irritating or dangerous chemicals
and/or ill-smelling chemicals. A typical fume exhaust hood is shown below.
Fume hood found in the laboratory
Exhaust hoods have fans to exhaust fumes out of the hood and away from the
user. The hood should be used when noxious, hazardous, and flammable
materials are being studied. It also has a shatterproof glass window, which
may be used as a shield to protect you from minor explosions. Reagents that
evolve toxic fumes are stored in the hood. Return these reagents to the hood
after their use.
Lab Manual vi CHE 1401
9. Never point a test tube that you are heating at yourself or your neighbour. It may
erupt like a geyser.
Beware of spattering
10. Do not perform any unauthorised experiments.
11. Clean up all broken glassware immediately.
12. Always pour acids into water, not water into acid, because the heat of solution
will cause the water to boil and the acid to spatter.
13. Avoid rubbing your eyes unless you know that your hands are clean.
14. NOTIFY THE INSTRUCTOR IMMEDIATELY IN CASE OF AN
ACCIDENT
15 Many common reagents, for example, alcohols, acetone, and especially ether, are
highly flammable. Do not use them anywhere near open flames.
16. Observe all special precautions mentioned in
experiments.
17. Learn the location of fire protection devices.
In the unlikely event that a large chemical
fire occurs, a powder extinguisher and a CO
2
extinguisher are available in the lab.
In order to activate the extinguisher, you
must pull the metal safety ring from the
handle and then depress the handle. Direct
the output of the extinguisher at the base of
the flames. The carbon dioxide smothers
Powder and CO extinguishers
2
the flames and cools the flammable material
quickly. If you use the fire extinguisher, be sure to return the extinguisher in at
the stockroom so that it can be refilled immediately. If the carbon dioxide
extinguisher does not extinguish the fire, evacuate the laboratory immediately
and call the security. One of the most frightening and potentially most serious
accidents is the ignition of one’s clothing. Therefore, certain types of clothing are
hazardous in the laboratory and must not be worn. Since sleeves are most likely
to come closest to flames, ANY CLOTHING THAT HAS BULKY OR LOOSE
SLEEVES SHOULD NOT BE WORN IN THE LABORATORY. Ideally,
students should wear laboratory coats with tightly fitting sleeves. Long hair also
presents a hazard and must be tied back. If a student's clothing or hair catches fire
Lab Manual vii CHE 1401
his or her neighbours should take prompt action
to prevent severe burns. Most laboratories have a
water shower for such emergencies. A typical
laboratory emergency water shower has the
following appearance.
In case someone's clothing or hair is on fire,
immediately lead the person to the shower and
pull the metal ring. Safety showers generally
dump 151 to 190 litres of water, which should
extinguish the flames. These showers cannot be
shut off once the metal ring has been pulled.
Therefore, the shower cannot be demonstrated.
(Showers are checked for proper operation on a
regular basis, however.)
18. Whenever possible use hot plates instead of
Bunsen burners.
A safety shower
Lab Manual viii CHE 1401
COMMON LABORATORY EQUIPMENT
Lab Manual ix CHE 1401
Lab Manual xi CHE 1401
EXPERIMENT 1
Basic laboratory techniques
OBJECTIVE
To learn the use of common, simple laboratory equipment.
Relates to chapter 1 of “Chemistry the Central Science, 12th Ed.”.
APPARATUS AND CHEMICALS
Balance Iron ring and ring stand
150-mL beaker Bunsen burner and hose
50- or 100-mL graduated cylinder Clamp
10-mL pipet Rubber bulb
25-mL Erlenmeyer flask Thermometer
125-mL Erlenmeyer flask
INTRODUCTION
Chemistry is an experimental science. It depends upon careful observation and the use
of good laboratory techniques. In this experiment you will become familiar with some
basic operations that will help you throughout this course. Your success as well as
your safety in future experiments will depend upon your mastering these fundamental
operations.
Because every measurement made in the laboratory is really an approximation, it is
important that the numbers you record reflect the accuracy of the device you use to
make the measurement. Our system of weights and measures, the metric system, was
originally based mainly upon fundamental properties of one of the world's most
abundant substances, water. The system is summarized in Table 1.1. Conversions
within the metric system are quite simple once you have committed to memory the
meaning of the pre-fixes given in Table 1.2. Recently, scientists have started to use a
briefer version of the metric system of units in which the basic units for length, mass,
and time are the meter, the kilogram, and the second. This system of units, known as
the International System of Units, is commonly referred to as the SI system and is
preferred in scientific work. A comparison of some common SI, metric, and English
units is presented in Table 1.3. Conversions within the metric system are quite easy if
you remember the definitions for the prefixes and use dimensional analysis in problem
solving.
Lab Manual 1 CHE 1401
Table 1.1 Units of Measurement in the Metric System
Measurement Unit and definition
3
Mass or weight Gram (g) = weight of 1 cubic centimeter (cm ) of water at 4°C and 760
mm Hg
Mass = quantity of material
Weight = mass x gravitational force
Length Meter (m) =100 cm =1000 millimeters (mm) =39.37 in.
Volume Liter (L) =volume of 1 kilogram (kg) of H O at 4° C
2
Temperature °C, measures heat intensity:
5 9
o o o o
C F 32 or F C 32
9 5
Heat 1 calorie (cal), amount of heat required to raise 1 g of water 1°C
1 cal = 4.184 joules (J)
Density d, usually g/ml, for liquids and g/L for gases:
d = mass/unit volume
Specific gravity Sp gr, dimensionless
Sp gr = density of a substance/density of a reference substance
The quantities presented in Table1.1 are measured with the aid of various pieces of
apparatus. A brief description of some measuring devices follows.
Table 1.2 The Meaning of prefixes in the metric system
Prefix Meaning Abbreviation
(power of 10)
-15
femto- 10 f
-12
pico- 10 p
-9
nano- 10 n
-6
micro- 10 µ
-3
milli- 10 m
-2
centi- 10 c
-1
deci- 10 d
3
kilo- 10 k
6
mega- 10 M
9
giga- 10 G
Table 1.3 Comparison of SI, Metric, and English Units
Physical quantity SI unit Some common Metric units Conversion factors
2
Length Meter (m) Meter (m) 1 m = 10 cm
Centimeter (cm) 1 m = 39,37 in.
1 in. = 2.54 cm
3 3
Volume Cubic Liter (L) 1 L = 10 cm
3 -3 3
Meter (m ) Milliliter (mL) 1L = 10 m
1L = 1.06 qt
3
Mass Kilogram (Kg) Gram (g) 1 kg = 10 g
Milligram (mg) 1 kg = 2.205 lb
1 lb = 453.6 g
Energy Joule (J) Calorie (cal) 1 cal = 4.184 J
Temperature Kelvin (k) Degree Celsius (°C) 0 K =- 273.15 °C
5
o o
C F 32
9
3
A mL is the same volume as a cubic centimeter: 1 mL = 1 cm
Lab Manual 2 CHE 1401
Laboratory Balance
A laboratory balance is used to obtain the mass of various objects. There are several
different varieties of balances, with various limits on their accuracy. Two of these
balances are pictured in Figure 1.1. Most modern laboratories possess single-pan
balances. These are the most accurate balances; generally, they are also the simplest
to use and are the most delicate and expensive. The amount of material to be weighed
and the accuracy required determine which balance you should use.
Figure 1.1 Digital electronic balances. The balance gives the mass directly when
an object to be weighed is placed on the pan.
Graduated Cylinders
Graduated cylinders are tall, cylindrical vessels with graduations
scribed along the side of the cylinder. Since volumes are
measured in these cylinders by measuring the height of a
column of liquid, it is critical that the cylinder has a uniform
diameter along its entire height. Obviously, a tall cylinder with a
small diameter will be more accurate than a short one with a
large diameter. A liter (L) is divided into milliliters (mL) such
that 1 mL = 0.001 L and 1 L = 1000 mL.
Graduated cylinder
Thermometers
Most thermometers are based upon the principle that liquids expand when heated.
Most common thermometers use mercury as the liquid. These thermometers are
constructed so that a uniform-diameter capillary tube surmounts a mercury reservoir.
To calibrate a thermometer, one defines two reference points, normally the freezing
point of water (0°C, 32°F) and the boiling point of water (100°C, 212°F) at 1 atm of
pressure (1 atm = 760 mm Hg). Once these points are marked on the capillary, its
length is then sub-divided into uniform divisions called degrees. There are 100°
between these two points on the Celsius, (°C, or centigrade) scale and 180° between
those two points on the Fahrenheit (°F) scale.
Lab Manual 3 CHE 1401
Pipets
Pipets are glass vessels that are constructed and calibrated so as to deliver a precisely
known volume of liquid at a given temperature. The markings on the pipet illustrated
in Figure 1.2 signify that this pipet was calibrated To Deliver (TD) 10.00 mL of
liquid at 25°C. Always use a rubber bulb to fill a pipet. NEVER USE YOUR
MOUTH A TD pipet should not be blown empty. It is important that you be aware
that every measuring device, regardless of what it may be, has limitations in its
accuracy. Moreover, to take full advantage of a given measuring instrument you
should be familiar with or evaluate its accuracy. Careful examination of the
subdivisions on the device will indicate the maximum accuracy you can expect of that
particular tool.
Figure1.2 A typical volumetric pipet, rubber bulbs, and the pipet filling technique.
In this experiment you will determine the accuracy of your 10-mL pipet. The
approximate accuracy of some of the equipment you will use in this course is given in
Table 1.4.
Not only should you obtain a measurement to the highest degree of accuracy that the
device or instrument permits, but you should also record the reading or measurement
in a manner that reflects the accuracy of the instrument. For example, a mass obtained
from an analytical balance should be observed and recorded to the nearest 0.01 g. This
is illustrated in Table 1.5.
Lab Manual 4 CHE 1401
Table1.4 Equipment Accuracy
Equipment Accuracy
Analytical balance ±0.0001 g (±0.1 mg)
Top-loading balance ±0.001 g (1 mg)
Graduated cylinder ±0.1 mL
Pipet ±0.02 mL
Buret ±0.02 mL
Thermometer ±0.2°C
Table 1.5 Obtaining Significant Figures
Analytical balance Top loader
85.9 g (incorrect) 85.9 g (incorrect)
85.93 g (incorrect) 85.93 g (incorrect)
85.932 g (incorrect) 85.932 g (correct)
85.9322 g (correct)
PROCEDURE
A. The Bunsen Burner
Melting points of metals
The Bunsen burner is a convenient source of heat in
the laboratory. Although there are several varieties,
their principle of operation is the same and is similar
to that of the common gas stove. The Bunsen burner
requires gas and air, which it mixes in various
proportions. The amount of air and gas mixed in the
chamber is varied by use of the collar illustrated in
Figure 1.3. The relative proportions of gas and air
determine the temperature of the flame.
Examine your burner and locate the gas and airflow
adjustments (valves) (see Figure 1.3). Determine how
each valve operates before connecting the burner to
the gas outlet. Close both valves; connect a rubber
hose to the gas outlet on the burner and the desk; then
open the desk valve about two-thirds of the way.
Figure1.3 Typical Busen burner.
Strike a match or use a gas lighter. Hold the lighted
match to the side and just below the top of the barrel
of the burner while gradually opening the gas valve on
the burner to obtain a flame about 7 or 10 cm high. Gradually open and adjust the air
valve until you obtain a pale blue flame with an inner cone as shown in Figure 1.3.
Flame temperatures can be observed using the melting points of metals.
Lab Manual 5 CHE 1401
Adjust the burner to a non-luminous flame to measure the temperatures in the various
regions of the flame. Use crucible tongs to hold 2-cm strips of iron wire, copper wire,
and aluminum wire in the various regions of the flame. The melting point of iron is
1535 °C, that of copper is 1083 °C, and that of aluminum is 660 °C. On the Report
Sheet, record the estimated temperature of the flame in the regions designated in
Figure 1.4.
Top of the outer cone
Center of the outer cone
Top of the inner cone
Metal Melting point
Center of the inner cone o
( C)
Iron (Fe) 1535
Copper (Cu) 1083
Aluminium (Al) 660
Figure 1.4 Regions of the flame for temperature measurement.
B. The Graduated Cylinder
Examine the 100-mL graduated cylinder and notice that it is scribed in milliliters. Fill
the cylinder approximately half full with water. Notice that the water meniscus
(curved surface of the water) is concave (see Figure 1.5). When water is the liquid,
the lowest point on the curve is always read as the volume, never the upper level.
Avoid errors due to parallax; different and erroneous readings are obtained if the eye
is not perpendicular to the scale. Read the volume of water to the nearest 0.1 mL.
Record this volume. Measure the maximum amount of water that your 125-mL
Erlenmeyer flask will hold. Record this volume.
+
proper position
+
Figure 1.5 Proper eye position for taking volume readings.
The meniscus reading here is 50.0 mL.
Lab Manual 6 CHE 1401
C. Using the balance to calibrate your 10-mL pipet
Weighing an object on a single-pan balance is a simple matter. Because of the
sensitivity and the expense of the balance (some cost more than 2500) you must be
careful in its use. Directions for operation of single-pan balance vary with make and
model. Your laboratory instructor will explain how to use the balance. Regardless of
the balance you use, proper care of the balance requires that you observe the
following:
1. Do not drop an object on the pan.
2. Center the object on the pan.
3. Do not place chemicals directly on the pan; use a beaker, watch glass, weighing
bottle, or weighing paper.
4. Do not weigh hot or warm objects; objects must be at room temperature.
5. Return all weights to the zero position after weighing.
6. Clean up any chemical spills in the balance area.
7. Inform your instructor if the balance is not operating correctly; do not attempt to
repair it yourself.
The following method is used to calibrate a pipet or other volumetric glassware.
Obtain about 40 mL of distilled water in a 150-mL beaker. Allow the water to sit on
the desk while you weigh and record the weight of an empty, dry 25-mL Erlenmeyer
flask (tare) to the nearest 0.1 mg. Measure and record the temperature of the water.
Using your pipet, pipet exactly 10.00 mL of water into this flask and weigh the flask
with the water in it (gross) to the nearest 0.1 mg. Obtain the weight of the water by
subtraction (gross – tare= net). Using the equation below and the data given in
Table 1.6, obtain the volume of water delivered and therefore the volume of your
pipet.
mass m
density
volume V
Normally, density is given in units of grams per milliliter (g/mL) for liquids, grams
3
per cubic centimeter (g/cm ) for solids, and grams per liter (g/L) for gases. Repeat this
procedure in triplicate-that is, deliver and weigh exactly 10.00 mL of water three
separate times.
Lab Manual 7 CHE 1401
The calculation is:
10.0025 g
V 10.0249 mL 10.02 mL
0.997770 g / mL
The volume must be rounded off to 10.02, because the pipet's precision can be
determined only to within ±0.02 mL.
The precision of a measurement is a statement about the internal agreement among
repeated results; it is a measure of the reproducibility of a given set of results. The
arithmetic mean (average) of the results is usually taken as the "best" value. The
simplest measure of precision is the average deviation from the mean. The average
deviation is calculated by first determining the mean of the measurements, then
calculating the deviation of each individual measurement from the mean and, finally,
averaging the deviations (treating each as a positive quantity). Study Example 1.2 and
then, using your own experimental results, calculate the mean volume delivered by
your 10-mL pipet. Also calculate for your three trials the individual deviations from
the mean and then state your pipet's volume with its average deviation.
EXAMPLE 1.2
The following values were obtained for the calibration of a 10-mL pipet: 10.10, 9.98,
and 10.00 mL. Calculate the mean value and the average deviation from the mean.
SOLUTION:
10.10 9.9810.00
mean 10.03
3
Deviations from the mean: value – mean
10.10 -10.03 = 0.07
9.98 - 10.03 = 005
10.00 - 10.03 = 0.03
0.07 0.05 0.03
Average deviation from the mean 0.05
3
The reported value is therefore 10.03 0.05 mL.
Lab Manual 9 CHE 1401
REVIEW QUESTIONS
You should be able to answer the following questions before beginning this
experiment:
1. What are the basic units of length, mass, volume, and temperature in the SI
system?
3
2. A liquid has a volume of 1.35 liters. What is its volume in mL? in cm ?
3. If an object weighs 1.47 g, what is its weight in mg?
4. Why should you never weigh a hot object?
5. What is precision?
6. Define density? Can it be determined from a single measurement?
7. What is the density of an object with a mass of 9.03 g and a volume of 0.1987
mL?
8. Weighing an object three times gave the following results: 10.2 g, 10.1 g, and
10.3g. Find the mean weight and the average deviation from the mean.
9. Normal body temperature is 98.6°F. What is the corresponding Celsius
temperature?
11. What is the weight in kilograms of 950 mL of a substance that has a density of
1.274 g/mL?
12. An object weighs exactly five grams on an analytical balance that has an accuracy
of 0.1 mg. To how many significant figures should this weight be recorded?
13. What is the dominant color of a properly adjusted flame from a Bunsen burner?
14. How many distinct cones does a properly adjusted non-luminous flame have on a
Bunsen burner (one, two or three)?
Lab Manual 10 CHE 1401
Experiment 1
Basic laboratory techniques
Name(s)
Date Laboratory Instructor
REPORT SHEET
A. Bunsen Burner
Indicate the approximate temperature of the following regions of the flame
(see Figure 1.4)
a. region : Top of the outer cone __________ °C
b. region : Center of the outer cone __________ °C
c. region : Top of the inner cone __________ °C
d. region : Center of the inner cone __________ °C
B. The graduated cylinder
Volume of water in graduated cylinder ___________________________ mL
Volume of water contained in 125-mL Erlenmeyer flask _____________ mL
C. Using the balance to calibrate your 10-mL pipet
o 3
Temperature of water ___________ C Density of water ___________ g/cm
Trial 1 Trial 2 Trial 3
Weight of Erlenmeyer (tare wt) ______ ______ ______ g
Weight of Erlenmeyer plus
10 mL H 0 (gross wt) ______ ______ ______ g
2
Weight of 10 mL of H O (net wt) ______ ______ ______ g
2
Volume delivered by 10-mL pipet ______ ______ ______ mL
show calculations overleaf
Mean volume delivered by 10-mL pipet __________ mL
show calculations overleaf
Trial 1 Trial 2 Trial 3
Individual deviations from the mean ______ ______ ______
Average deviation from the mean ____________________ mL
show calculations overleaf
Volume delivered by your 10-mL pipet ____________ mL ± __________mL
Lab Manual 11 CHE 1401
EXPERIMENT 2
Identification of substances: Physical properties
OBJECTIVE
To become acquainted with procedures used in evaluating physical properties and the
use of these properties in identifying substances.
Relates to chapter 1 of “Chemistry the Central Science, 12th Ed.”.
APPARATUS AND CHEMICALS
Balance Capillary tubes (5)
250 mL beaker Spatula
25 mL Erlenmeyer flask Ring stand and ring
10 mL graduated cylinder Utility clamp
10 mL pipet Thermometer clamp
5 mL pipet Thermometer
50 mL beakers (2) Stirring rod
Burner and hose Apparatus for boiling point determination
Wire gauze Naphthalene (1 g)
Small rubber bands Ethyl alcohol (15 mL)
Boiling chips Cyclohexane (20 mL)
Large test tubes (2) 2 unknowns (liquid and solid)
Small test tubes (6) Soap solution
Test-tube rack
DISCUSSION
PROPERTIES are those characteristics of a substance that enable us to identify it and
to distinguish it from other substances. Direct identification of some substances can
readily be made by simply examining them. For example, we see color, size, shape,
and texture, and we can smell odors and discern a variety of tastes. Thus, copper can
be distinguished from other metals on the basis of its color.
PHYSICAL PROPERTIES are those properties that can be observed without altering
the composition of the substance. Whereas it is difficult to assign definitive values to
such properties as taste, color, and odor, other physical properties, such as melting
point, boiling point, solubility, density, viscosity, and refractive index, can be
expressed quantitatively. For example, the melting point of copper is 1087 °C, and its
3
density is 8.96 g/cm . As you probably realize, a specific combination of properties is
unique to a given substance, thus making it possible to identify most substances just
by careful determination of several properties. This is so important that large books
have been compiled listing characteristic properties of many known substances. Two
of the most complete references of this type that are readily available today are The
CRC Handbook of Chemistry and Physics and Lange’s Handbook of Chemistry.
In this experiment you will use the following properties to identify a substance whose
identity is unknown to you: solubility, density, and boiling point.
Lab Manual 12
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