Introductory Laboratory Manual
Reporting Sheets
This record book belongs to: …………………………………….
Name……………………………
Workplace protocols
1. Safety Procedures
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Consult Safety Data sheets* and
method of analysis for advice on
hazards and precautions to be taken
Wear appropriate PPE
Use fume hood etc as necessary
Maintain tidy workspace
Exercise care not to endanger other
people
Observe emergency procedures
Report spillages and all accidents
2. Recording and Reporting
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
Register samples into laboratory
system
Label samples
Record which tests the sample should
undergo
Record sample description, compare
with specification, record and report
discrepancies
Record calibration results for
instruments/equipment in tables and/or
charts, following quality system
Keep records of calibration status and
calibration schedule for instruments /
equipment
Report faulty equipment
Keep records of solutions prepared, by
expected use-by date, and by name of
person who prepared them
Record results legibly, and chart when
required to identify trends
Interpret trends
Identify and report atypical results
promptly to appropriate personnel
Record approved results into workplace
system
Comply with quality system
Report all accidents and potential
hazards
Maintain confidentiality of workplace
information
3.
Sample Handling
(a)
(b)
Maintain sample integrity
Prepare sample and standards for test
4.
Testing
(a)
Refer to workplace procedures
manual for standard method
Conduct tests according to workplace
procedures
Clean up spills promptly
Record results according to
workplace procedures, without
alteration
Calculate results, checking against
expected values and correcting errors
Trouble shoot basic problems with
procedure or equipment which have
led to atypical results
(b)
(c)
(d)
(e)
(f)
5.
Equipment and Reagents
(a)
(b)
(g)
Set up equipment and reagents
Check calibration status of
equipment; calibrate if necessary
Monitor shelf-life of working solutions
Prepare solutions when necessary,
label and log into laboratory register
Clean and care for test equipment
and work space
Dispose of faulty equipment or
quarantine it for repair
Store unused reagents
6.
Wastes
(a)
(b)
Minimise generation of wastes
Collect, sort and dispose of wastes in
accordance with procedures
identified in SDS
7.
(a)
Environmentally specific
Equipment not in use is turned off at
the power switch
Lights are off when laboratory is
unattended
Fume cupboards are off when not in
use
Non-conformances with
environmental standards are reported
(c)
(d)
(e)
(f)
(b)
(c)
(d)
* SDS’s were up until January 1 2012
referred to as MSDS (Material Safety Data
Sheets)
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Work place Protocols Sign-off sheet
This sign-off sheet is to be completed after each laboratory session. It is to be
handed in at the end of semester 1 and will be used as evidence for the Participation
in Environmentally Sustainable Workpractice Unit
Date
Time
Non-conformance
Action
Signature
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Name……………………………
Date
Time
Non-conformance
Action
Signature
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Name……………………………
Safety in the Laboratory
Purpose:
This section is designed to provide a brief overview of work safety in the laboratory.
You will need to refer to the text for laboratory safety for additional information.
Occupational health and safety laws have greatly improved safety and well being in
the workplace. All employers must provide safe and healthy work conditions, all
workers must work within the safety systems and both groups must accept
responsibility for identifying and controlling hazards and minimising risk of harm.
These laws are continually being reviewed and the current Work Health and Safety
Act 2011 resulted in a change from 1 January 2012.
Any laboratory has a range of hazards that need to be controlled to minimise the risk
of harm.
A working laboratory is really not much different to working in your home
kitchen!
What is a hazard?
What is risk?
What does hazard control mean?
What controls are available for different hazards?
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Chemicals can be hazardous because of a range of properties. They may be:

toxic/poisonous

irritating

flammable

explosive

corrosive

mutagenic, carcinogenic, teratogenic
Effects may be acute or chronic.
A chemical is only dangerous if it enters your body. This can only occur by:

inhalation

absorption

ingestion

injection
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What controls exist for each of these chemical hazards?
The law (Work Health & Safety 2011) now requires information sources about
hazardous chemicals to be supplied. They are called Safety Data sheets (SDS) and
they help you to find out about dangerous properties of chemicals and what
measures to take to reduce harmful effects.
Typically a SDS provides information about:








common names and identification codes for the material
physical properties
major hazards of the material
acute and chronic symptoms of exposure
exposure standards
medical advice
spill and other emergency responses
others
Use the SDS provided and identify information relating to the hazardous
nature of the material.
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Laboratory rules and regulations
1. Always wash your hands before you leave the laboratory
2. Only supervised work is permitted in the laboratory
3. Chemicals and equipment are not to be taken from the laboratory
4. Safety glasses, laboratory coats and appropriate shoes must be worn in the
laboratory at all times
5. Clean-up spills immediately
6. Act responsibly - the laboratory is not a playground, racetrack or amusement
parlour
7. Long hair must be tied back
8. You must be aware of the location and operation of safety equipment
9. All accidents and incidents must be reported
10. Consult the SDS for unfamiliar chemicals
11. Spillage of any chemical on the skin or eyes should be immediately treated with
copious quantities of water and the supervisor’s attention sought
12. Eating and drinking in the laboratory is banned
13. Fume cupboards should be used for work involving dangerous gases or vapours
The Laboratory is a safe place to work if you follow the rules
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Practical 1.1 Laboratory Layout
Date completed:
Purpose
_____________________ Teacher Check _______________
Analyst signature ____________
To become familiar with the layout of the work area, in particular, those areas and
pieces of equipment dealing with safety. Procedure:
Draw a map of the laboratory, which shows the location of the following features:
Fire extinguishers, fire exits, fire control equipment; special storage cupboards,
safety showers, eye wash stations, first-aid, fume cupboards, antidotes, laboratory
store, ovens, balances, waste disposal facilities.
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Name……………………………
Practical 1.5 Safety in the laboratory
Date Completed:
_____________________ Teacher Check ______________
Procedure:
Analyst signature ____________
Observe the demonstrations on safety in the laboratory
Give a brief description of the demonstration
List the observations you made during the class and in the next laboratory session
Comment on aspects of the demonstration that you found interesting, disturbing,
informative etc
Results:
Test/
Demonstration
Observation
Comments
Hydrochloric acid
HCl
+
Meat
Sulfuric acid
H2SO4
+
Meat
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Test/
Demonstration
Observation
Comments
Nitric Acid
HNO3
+
Meat
Sodium
Hydroxide
NaOH
+
Meat
Ammonium
hydroxide
NH4OH
+
Meat
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Test/
Demonstration
Observation
Comments
Propanone
Acetone
CH3COCH3
+
Meat
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Practical 1.2
Date Completed:
Laboratory signs and labels
___________________ Teacher check _____________
Procedure
Analyst signature ____________
Observe the laboratory signs and labels in the laboratory and throughout the
building. Fill in the table below with at least six examples to show your understanding
of each column heading:
Sign identifier
eg exit, fire, no
smoking, etc
Message being
conveyed
Significant
aspects of the
colour scheme
Location
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Sign identifier
eg exit, fire, no
smoking, etc
Message being
conveyed
Significant
aspects of the
colour scheme
Location
Questions:
Answer the following general questions about the signs and labels found in the
laboratory and surrounding areas
1. Why are signs important in the laboratory?
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2. List:
 other signs and labels which you believe could be necessary

places in the laboratory where these missing signs should be located
3. Why do you think that smoking is not allowed within 10 metres of the building?
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Practical 1.3
Date Completed:
Procedure:
Laboratory hazards
__________________ Teacher check ___________________
Analyst signature ____________
Identify the hazards that you have found in the laboratory and indicate how you can
work safely with these hazards. Use the table of physical, chemical and biological
hazards given earlier for some ideas.
Results:
Hazard
Possible effects of
hazard
Control measures
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Hazard
Possible effects of
hazard
Control measures
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Observation skills are particularly important in aspects of laboratory work. We
use all senses to assist in working safely and also in noting aspects of our practical
work
Take a candle and:
1. Make as many observations as you can about your candle.
2. Light your candle and record all your observations
3. Blow out your candle and record your observations
4. Identify your observations as qualitative or quantitative
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Name……………………………
Practical Equipment identification (Part 1)
Date Completed:
__________________ Teacher check ___________________
Procedure:
Analyst signature ____________
The following table lists basic apparatus used in the laboratory. Complete the table
by giving a use for the equipment and any safety features that need to be
considered.
Diagram
Name
Use / Safety/ Range of sizes
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Diagram
Name
Use / Safety/ Range of sizes
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Diagram
Name
Use / Safety/ Range of sizes
`
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Diagram
Name
Use / Safety/ Range of sizes
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Diagram
Name
Use / Safety/ Range of sizes
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Practical work 5.1
Basic material handling techniques
Date Completed: ______________________ Teacher check ________________
Purpose:
Analyst signature ____________
All chemicals whether solid, liquid or gas must be handled with caution. This
practical looks at the techniques to be employed when transferring solids and liquids.
Procedure:
Observe the demonstrations of material transfer shown by your trainer. Identify the
mistakes and indicate how the process should be completed.
Procedure
Errors
Corrections
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Practical Liquid handling
Date Completed: ______________________ Teacher check ________________
Purpose:
Analyst signature ____________
Use the equipment provided to practice pouring and transferring liquids from one
container to another. Complete the following table .
Equipment
Major Application
Convenience of Use
Winchester bottle
Laboratory storage bottle
Aspirator
Measuring cylinder
Beaker
Conical flask
Evaporating basin
Sample tubes
Desiccator
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Practical work 5.3A Introductory Volume Handling
Measurements
Date Completed: ______________________ Teacher check ________________
Procedure:
Analyst signature ____________
For all workstations complete the table following the instructions provided
Results:
Workstation 1
Identify the container, its accuracy and the volume contained.
Vessel name
Workstation 2
Volume
How accurate is your
measurement?
Identify the equipment needed to transfer the volumes
Vessel name
Specified volume
Teacher’s Signature
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Practical work 5.2A
Introductory weighing task
Date Completed: ______________________ Teacher check ________________
Purpose
Analyst signature ____________
The aim of the practical is to become familiar with the different types of balances
available in a general laboratory. Your instructor will demonstrate the correct
procedures to follow when using a balance.
Procedure:
Use the range of laboratory balances supplied as shown during your teacher’s
demonstrations. You will perform repeated measurements which will be used to
check your accuracy and that of the balances. Record the capacity and sensitivity of
the balances.
Results:
Balance
Object Code ........
Object Code........
Object Code ........
Triple Beam:
Capacity: ...........
Sensitivity;..........
3 dp top pan
Capacity: ...........
Sensitivity ..........
4 dp analytical
Capacity ............
Sensitivity .........
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Practical work 5.5A
Simple filtration
Date Completed: ______________________ Teacher check ________________
Purpose:
Analyst signature _____________
To become familiar with simple filtration techniques, following instructions and noting
safety requirements.
Note: The chemicals in this practical are very toxic. Ensure that any spills are
reported and also ensure that hands are properly washed if skin contact occurs and
before leaving the laboratory.
1. Record the identity and quantity of each of the chemicals
2. Dispense an aliquot for each reagent bottle into a clean dry beaker
3. Carefully mix, using a glass stirring rod, the beaker contents over a steam bath
for five minutes
4. Cool the beaker in an ice bath
5. Set up a filtration apparatus as shown by your teacher and using a labelled, preweighed filter paper filter your sample.
6. Wash the filter cake well with distilled water
7. Transfer the filter cake and filter paper to a labelled watch-glass and allow to dry
8. Reweigh and determine the amount of solid material.
Results:
Identity of solution 1
Volume of solution 1 used (mL)
Identify of solution 2
Volume of solution 2 used (mL)
Mass of empty filter paper (g)
Mass of filter paper + precipitate (g)
Mass of precipitate (g)
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Questions:
1. When is filtration a suitable method of separation?
2. One of the solutions you worked with contained lead. Why is it necessary to be
extremely careful when working with this chemical? How would you find out the
necessary safety requirements for working with lead solutions?
3. Why was it necessary to stir the solution over a water bath?
4. Why was it necessary to allow the solution to cool before filtration?
5. When filtering the solution is not filled to the top of the filter paper, why?
6. Draw a diagram to represent the simple filtration apparatus.
7. List all the possible places where losses may have occurred.
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Practical: 4.4
Heating devices
Date Completed: ______________________ Teacher check ________________
Procedure:
Analyst signature ____________
Examine the heating equipment on display and complete the following table.
Device
Description
Major Use
Safety Hazards
Flame dependent
devices
(Burners)
 Bunsen
 Meker
 Batswing
 Microburner
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Device
Description
Major Use
Safety Hazards
non – flame
devices
 Heating
mantle
 Electric hot
plate
 Muffle furnace
 Laboratory
drying oven
 Heat lamp
 Steam / water
/ sand baths
Others
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Device
Description
Major Use
Safety Hazards
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Practical:
Application of heating equipment
Date Completed: ______________________ Teacher check ________________
Procedure:
Analyst signature ____________
Follow the instructions for each task and record the data where required.
Task 1
1. Unscrew the stack on each of the supplied burners and examine the features of
each burner. Note the gas jet or nipple and the rotatable sleeve which admits air
and mixes it with the gas as they moves up the stack.
2. Attempt to light the gas at the nipple. Note - the gas supply may need to be very
low for this.
3. Replace the stack and light the Bunsen as demonstrated by your teacher.
4. Note the effect of sleeve positioning on the appearance of the flame.
5. Using the blue flame, turn the gas pressure down slowly so that the flame gets
smaller and strikes back down the stack to burn at the gas nipple.
This condition is extremely dangerous because:
 the Bunsen appears to be off and hence is a fire hazard
 the stack will be heated by the flame and will burn anyone who touches it
6. Repeat the above five steps with the Meker and micro-burners.
Draw and label a Bunsen and discuss your observations below
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Task 2
Use the supplied thermocouple to measure the temperature of various zones in both
the ‘blue’ and ‘yellow’ versions of the Bunsen flame.
Complete the following table:
Zone of the flame
being measured
Yellow Flame
temperature
Blue Flame
temperature
(OC)
(OC)
Diagram to locate each
zone
Approx. 20cm
above the tip of
the flame
At the tip of the
flame
20
cm
In the heart of the
flame
(top of blue cone)
Level with the
stack opening
Task 3
This section is designed to investigate the changes which occur to the gas mixture in
the flame.
Following the demonstrations given by your teacher, examine the presence of zones
of unburnt gases in a Bunsen burner as follows:
1. Use a thin glass tube inserted directly into the bottom of the blue cone to tap off
some of its contents – attempt to ignite the gases at the other end of the tube
2. Pierce a live match with a pin inserted at right angles approximately half way
along the match – suspend this match with its head pointing up, on the stack of
an unlit Bunsen. Light the Bunsen, with the air hole open.
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Observations
Record your observations and provide an explanation of what is happening.
Task 4
This section tests the efficiency of heating water in various containers with different
heating equipment. You are to report on:



the time taken for the water to boil
the amount of heating control you have
the safety of the method.
Each of the containers should be about one third filled and heated as shown by your
teacher.
Container
Heating
device
Time to boil
(sec)
Controllability
or efficiency
Safety
hazards
micro test tube Bunsen
micro test tube micro burner
test tube
Bunsen
test tube
micro burner
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Container
Heating
device
boiling tube
Bunsen
boiling tube
micro burner
Beaker
Bunsen
Time to boil
(sec)
Controllability
or efficiency
Safety
hazards
(100 - 150mL)
Beaker
micro burner
(100 - 150mL)
Beaker
steam bath
(100 - 150mL)
Beaker (100 -
electric hotplate
150mL)
Questions:
What is the major safety hazard when boiling liquids in test tubes?
Which of the following would be suitable to heat water to boiling?




heating mantle
muffle furnace
laboratory drying oven
hair drier
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Practical 5.4A Introductory Solution Preparation
Date Completed: ______________________ Teacher check ________________
Procedure:
Analyst signature ____________
You are required to prepare and validate known concentration solutions.
Using an analytical balance weigh out accurately the mass of each solute indicated
in the result sheet table.
Quantitatively transfer the solid to a 100mL volumetric flask and make up to the mark
with distilled water
The teacher will show you the checks to be made on your sample and the previously
prepared sample
Results:
Potassium Hydrogen Phthalate (Labelled as KHP) mass = 1.0 ±0.1g
Your Solution readings
Standard Sample readings
Sample mass:
Sample volume:
pH reading
Conductivity
Potassium chloride (labelled as KCl) mass = 5.0 ± 0.5g
Your Solution readings
Standard Sample readings
Sample mass:
Sample volume:
pH reading
Conductivity
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Questions:
1. Why is it important that an analytical balance is used to measure the mass?
2. Why is it important that the transfer of solid material is quantitative?
3. Why was a volumetric flasks specified in each case?
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Laboratory Safety Checklist
Laboratory
Date
Time
Auditors
Y/N
General Safety Aspects
Is t h er e t h e ap p r o p r iat e n u m b er o f t r ain ed f ir st aid
p er so n n el o n sit e?
Are the first aid cabinets accessible, of the correct type, and
up to date?
Is laboratory signage correct?
Is suitable personal protective equipment available, and properly
maintained?
Are the staff trained in laboratory safety procedures?
Is there an accident incident reporting system in place?
Are all the standard operating procedures for the laboratory
readily available, and are they followed?
Comments
Y/N
Housekeeping
Are the floors clean?
Are there any trip hazards or old equipment lying on the floor?
Is the shelving the correct height and stable?
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Are the walkways clearly marked and free of obstruction?
Y/N
Environment
Are appropriate waste management procedures in place?
Are wastes segregated and stored correctly?
Are wastes correctly labelled and documented?
Is there storage and disposal of broken glass and sharps?
Are appropriate waste management procedures in place?
Comments
Y/N
Fire
Are suitable fire extinguishers fitted and are there the appropriate
number?
Are the locations of extinguishers accessible and well identified?
Have all extinguishers hydrants and hose reels been checked in the
last 12 months?
Are all built in fire protection devices unobstructed and operational?
Are the staff trained in the use of fire fighting equipment?
Is emergency lighting install?
Is the emergency evacuation plan displayed, understood by all, and
practiced regularly?
Are suitable fire extinguishers fitted and are there the appropriate
number?
Comments
Y/N
Egress
Are all emergency exits clearly marked and unobstructed?
Are exit doors unlocked?
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Is the number of emergency exits appropriate?
Comments
Y/N
Manual Handling
Have all personnel been trained in correct manual handling and lifting
techniques?
Are lifting aids and trolleys readily available for any devices requiring
them?
Comments
Y/N
Emergency Procedures
Are all workplace emergency procedures clearly outlined and known
by all personnel (fire evacuation, spill procedures etc.)?
Are all emergency teams in place and trained in their duties?
Is there a display of emergency evacuation plans with appropriate you
are here sign indicating a method of egress?
Comments
What other areas of the TAFE laboratory should be checked in a safety audit?
Analyst signature ____________
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Open ended project
You have been working in your chemistry class and laboratory class towards an
understanding of basic concepts in both the laboratory and chemistry,
This task is designed to enable you to show your competence in both areas.
You are to devise a simple laboratory project that will allow you to separate a mixture
of sand, salt and sawdust and provide the percentage composition of the original
mixture. You will be guided in class by your laboratory teacher and also your
chemistry teacher.
Requirements:
1. Submission to your teacher of a flow chart showing the general
laboratory procedure
2. Identification of the physical And/or chemical properties you will use to
make the separation
3. A completed laboratory request form for each practical session
4. Completed 5 minute risk assessments for each practical session
5. A work journal indicating how your ideas changed each session
6. A log book that records your data in a scientific manner
7. A written report following the format provided by your teacher
You will be required to submit a report at the conclusion of the project.
The following questions could be useful as you design your project:








What properties of each component could be useful for separation?
What equipment will you require for the separation? Is it readily available in the
laboratory?
What hazards exist in your separation procedures?
What SDS will you require?
Do you need to know the original mass of the mixture?
How many sessions do you need for the separation?
Are there other methods that could work? Why did you choose a particular
method?
Why is it important to have a logbook for your data?
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Basic Arithmetic
These exercises are designed to give you practice in the basic mathematical
concepts required for successful completion of the course. The maths is generally
not difficult but the application of the techniques to the chemical world may challenge
even the best mathematician . Lots of practice will ensure you are competent and
therefore able to successfully complete the assessments.
1. Use of the calculator
2. Estimation
3. Rounding
4. Order of operations
5. Scientific notation
6. Directed numbers
7. Significant figures
8. Substitution into a formula
9. Rearranging a formula
10. Basic graphing
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1. Use of the calculator
All calculators operate slightly differently but all should give the same answer for a
particular calculation. If the answer is not correct then it is most likely that the
operator, you, has incorrectly entered data or not followed appropriate mathematical
logic.
You should know how the following functions operate on your calculator
square root
log 10 (normally called log or log10)
10x (often on the same button as log10)
memory (store, add, recall)
EXP for scientific notation
The best way to work our how your calculator operates is to read the manual…but
they are very thick and this will most likely not occur.
The next best way is to try some calculations that you know the expected answer.
Exercise
6 +2 x 3 =
(12)
5-4 x 3 =
(-7)
16 x 4 + 2 x 3
=
(70)
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2. Estimation of result
The calculator result is only as good as the operator ie if you enter an incorrect number or
do not use correct mathematical logic the answer will be wrong. You should have an idea
of the expected answer, not just trust the calculator.
Basic process for estimation
1.
2.
3.
4.
Round all numbers to one non-zero digit
Calculate the values inside any brackets and round the results.
Cancel out any zeroes where possible.
Calculate estimate.
Example
Estimate the answer to the calculation from Example 1.2.
(63.8  1.94) x 0.0547
0.626 x 10
1.
Round all the numbers
(60  2) x 0.05
0.6 x 10
2.
Calculate inside the brackets and round result.
60 x 0.05
0.6 x 10
3.
Remove spare zeroes.
6 x 0 .5
6 x1
4.
Calculate estimate.
0.5 (the exact answer was 0.541).
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1. Choose the best approximation A, B or C for these calculations
Calculation
Approximation
A
B
C
6.93 x 11.2
7.76
77.6
776
7.82 x 5.03
39.3
393
3930
0.31 x 0.186
5.77
0.577
0.0577
5.91 x 21.14
11.9
119
1.190
0.00467 x 3.175
0.0148
0.00148
0.148
426.8 x 0.507
21.62
216.2
2.162
Obtain an approximate answer to each calculation and compare it with the exact value
using your calculator
a)
72.9 + 8.473
b) 0.0417 + 1.38 + 0.00209
c) 324.1 – 20.69
d) 82.01 + 3.97 -70.16
e) 0.003 x 0.0206
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Now try these
(i)
0.112 x 25.3
=
12.5
(ii)
24,300 x 16.8
=
8.314 x 298
iii)
(23.93  181.69) x 0.123
 77.7 =
87.6  1.45
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3. Rounding
To round off to a stated accuracy the last figure to be retained is corrected depending on
the digit which follows. A typical rounding system states that if the following digit is 5, 6, 7,
8 or 9 then the last figure is taken up one.
Example
Round off correct to the nearest whole number
2463.62  2464
Round off correct to two decimals places
7.2048  7.20
Round off correct to the nearest thousand
849801  850000
Exercise
1. Round off to the nearest whole number

2344.62

16.403

7.9

0.735

829.99
2. Round off correct to the nearest figure as shown in brackets)

6.4137 (2 d.p)

36.45071 (3 d.p)

0.003682 (4 d.p)

5.20196 (2 d.p)

463.9 (tens)

8 420 (hundreds)

46 375.9 (hundreds)

68 420 (ten thousands)

4 724 361 (millions)

89 840 000 (10 millions)
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4. Order of Operations
The rules for order of operations are:
1. Brackets first
2.  and  from left to right second
3. + and – from left to right third
Exercise
1. 5 x 4 - 1
=
2. 6 + 10  2
=
3. 27 - 4 x 2
=
4. 2 x (3 + 6)
=
5. 6 x 4  2
6. 3 + 4 -2
=
=
7. (2 + 3 x 6) + 1
=
8. 4 x 2 + (3 + 1) =
9. 24  4  2
=
10. [(3 + 2) + 4 x 2] + 2 x 2
11.
52  4
8
=
12.
63
63
=
13.
3x 2  3
3
=
14.
8  2 1
5  2 x2
=
=
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15.
12  24  6
64  8
=
16.
16  (4 x 2)
56  7
=
17.
4  4 x8
=
18. 122  52
=
19. 12 – (20 – 3 x 6)2
20.
13  31  2 x3
2
=
=
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5. Scientific Notation
Scientific notation is a method for writing very large and very small numbers in the
form of a number between 1 and 10 and a power of 10.
Example…
Avagadro’s Number, the number of entities in a mole is a number that the mind has
difficulty understanding.
602000000000000000000000
Written in Scientifc notation the number is 6.02 x 1023
If the index number is positive it indicates that the number is large and the decimal
point has been moved right to left
If the index number is negative it indicates the original number is small (less than 1)
and the decimal point has been moved left to right
Exercises
Write in scientific notation
1. 720 000
2. 15 000 000
3. 896.5
4. 8076
5. 0.005
6. 0.000 001 3
7. 0.000 009
8. 10 100 000
9. 0.000 246
10. 21 000
11. 32578.3
12. 0.000489
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Write the original number for
13.
5.2 x 106
14.
2.015 x 10-3
15.
4.6 x 104
16.
1.11 x 1011
17. 3.33 x 10-4
18. 3.487 x 103
19. 8.47 x 10- 5
20. 7.010 x 10 4
21. 9.02 x 102
22. 1.587421 x 104
23. 4.59 x 105
24. 3.574 x 10 -3
25. 2.0846154 x 10 4
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6. Directed numbers
To multiply or divide

Two positive numbers give a positive number

Two negative numbers give a positive number

A positive and a negative number gives a negative number
1. 6 + 2 (-2)
=
2. (-3) + 3
=
3. (-5) x 6
=
4. -15  5
=
5. -8 x -3
=
6. Given a = -1, b= 2, c = -4 d = -3
Evaluate

abc
=

d2
=

a3
=

a+b+c+d
=

2b c
=

ab – cd
=

-(-d)
=
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7. Significant Figures
Significant figures are defined as follows:
1. All non-zero digits are significant
2. Zeros at the end of a whole number or at the beginning of a decimal are not
significant
3. Zeroes between non-zero digits are significant
4. Zeroes at the end of a decimal are significant
Examples
1. 34 100 has 3 significant figures
2. 6010 has 3 significant figures
3. 0.0042 has 2 significant figures
4. 0.0380 has 3 significant figures
Exercise
1. Give the number of significant figures in each of these numbers

478 200

4 606

0.01003

3000

863.9462
2. Rewrite each of these numbers
i) correct to 2 sig fig
ii) correct to 1 sig fig

62 481.69

459

0.0003816
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
0.00204

3.004

86 200 000

0.00004937

2450
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8. Substitution into a formula
Often the calculations you will have to do use provided formulae which are supposed
to make the process of getting the right answer easier. A formula is simply a
calculation where the numbers are replaced by symbols.
In substitution the pronumerals are replaced with numerical values and the
expression evaluated
An application of this is the formula for moisture content in Example 1.1.
EXAMPLE 1.1
You are analysing soil for its moisture (water) content. You weigh out soil into a
basin weighing 75.2826 g, until the balance records a weight of 85.9837 g. After 2
hours of drying, the basin and dried soil weighs 82.5832 g.
 m  md 
 x 100
Moisture content (%)   w
m

m
b
 w
where
mb is the mass of the empty basin = 75.2826
md the mass of the basin with dried soil = 82.5832
mw the mass of the basin with wet soil = 85.9837
 85.9837  82.5832 
 x 100  31.78%
Moisture content (%)  
 85.9837  75.2826 
Other formulae often used in the laboratory include:
C1V1 = C2V2




C1 is the concentration of the first (more concentrated) solution
V1 is the volume of the first (more concentrated) solution
C2 is the concentration of the second (diluted) solution
V2 is the volume of the second (diluted) solution
C



the dilution equation
m
V
a concentration equation
C is the concentration is g/L,
m the mass in grams
V the volume in L.
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Name……………………………
Exercise
Substitute the given values and find the variable indicated.

V = E – IR

a= .

P = 2(l + b)

C= πd

A = 2(lb + lh + bh) Find A when l =5, b = 8, h = 13

A = ½ h ( a + b)
Find V when E = 4.61, I = 0.78 R = 5.31
uv .
u + v
Find a when u = 10.82 and v = 7.38
Find P when l = 38 amd v = 7.38
Find C when d =32.6 (check your calculator for π)
Find A when h = 39, a = 20, b= 23
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9. Rearranging formula to solve equations
If the unknown in an equation is not the subject of the formula than the formula must
be rearranged in order to obtain an answer. The process is simple as long as the
rules are followed:
Equations may be simplified and solved by:
1.
2.
3.
4.
adding the same number to both sides
subtracting the same number from both sides
multiplying both sides by the same number
dividing both sides by the same number
Example
x + 8 =4
(to remove the 8 we need to subtract 8, but from both sides)
x = 8–8 = 4–8
x = -4
6 x d = 42
(to remove the 6 we need to divide both sides by 6)
6 x d = 42
6
6
d =7
Exercise
Solve the following equations
1. c + 18 = 13
2. t – 8 = - 8
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3. 4a = 2.4
4. 8 t = 4
5. y – 2.8 = 0.6
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The same process can be used when substituting into formula
Example 1
C
m
V
rearrange to make m the subject of the formula
In order to remove the V we need to multiply each side by V
CxV = m xV
V
CxV=m
Example 2
C1V1 = C2V2 rearrange to make V1 the subject of the formula
In order to remove C1 from the left hand side we need to divide both sides by C 1
C1V1 = C2V2
C1
C1
then
V1 = C2 V2
C1
Exercise
Rearranging the following formula to make the symbol in brackets the subject.
(a)
C
m
(V)
V
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(b)
C1V1 = C2V2
(C2)
(c)
Tc = 0.556Tf – 17.8
(d)
C
(Tf)
m
(m)
V
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10. Basic graphing techniques
Graphs are one of the clearest and most useful ways to express results.
The basic graph is drawn by hand and should follow the following rules:
 Graph should have a title
 Graph should have a scale for each axis that is easy to read and
interpret and is labelled with the appropriate units


Data points should be clearly marked either with a X or ‫ סּ‬or something
similar
A line (or curve) of best fit should be used to identify the trend
A more advanced method of determining an unknown value is to work with the
equation for the line. This will be dealt with in a later resource.
PRESENTATION OF LABORATORY DATA
Purpose
This exercise examines different formats for the presentation of numerical data.
Preliminary information
Consider the following pilot plant data : At 12:23 pm the pressure in the vessel was 123.4 kPa. The
stirrer was then switched on and the special catalyst was added. Readings of pressure were taken for
the next two hours and the following data collected:
12:24 pm 125.6 kPa; 12:25 pm 126.7 kPa; 12:26 pm 127.9 kPa; 12:28 pm 130.1 kPa; 12:30 pm 131.6
kPa; 12:32 pm 135.6 kPa; 12:34 pm 135.1 kPa; 12:41 pm 133.6 kPa; 12:44 pm 129.8 kPa; 12:54 pm
127.6 kPa; 12:59 pm 126.3 kPa; 13:11 pm 125.9 kPa; 13:54 pm 123.8 kPa; no change thereafter.
Procedure
1. Organise this data as a table with columns for Time, Elapsed time (min.) and
Pressure (kPa).
2. Organise this data as three graphs, each with Pressure on the vertical axis and Time
on the horizontal axis. The graphs must have the following formats:
•
graph 1 — time plotted 00:00–24:00hr and pressure 0–200 kPa. Join
the dots.
•
graph 2 — elapsed time plotted 0–100 min. and pressure 120–140
kPa. Join the dots.
•
graph 3 — the graph which best eliminates the faults of (i) and (ii) and
is fitted with a smooth curve (curve of best fit).
Questions
1. Why is a graph so successful in displaying numerical data?
2.
Why is graph 1 inferior to graph 2?
3.
What information is conveyed in graph 3 about the process?
4.
Can you suggest a sensible tactic for deciding how to choose axis dimensions for
plotting any set of data?
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Name……………………………
Now try these graphing questions
a. The following results were obtained from an experiment in which the
absorbance of various solutions was measured.
Concentration
(mg/L)
Absorbance
50
100
150
200
250
0.13
0.28
0.25
0.53
0.64
1. Plot the data on a graph to show the absorbance as a function of the
concentration
2. An error was made in one of the readings. Circle and reject the outlying
value
3. Draw a line of best fit using only the reliable data points
4. Find the concentration of a solution with an absorbance of 0.2
5. What would be the absorbance of a 160 mg/L solution
b. During the expansion of a particular mass of gas at constant pressure, the
following readings were taken
Volume (mL)
400
Temperature (oC)
100
600
150
800
1000
1200
1400
1600
200
250
300
350
400
1. Using volume as the vertical axis, plot these points and draw a straight
line through them’
2. What was the volume when the temperature was at 325 oC
3. At what temperature was the volume 520 mL
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General Revision of Concepts
Given the following data and formulae, calculate the values of the unknown,
reporting the result to an appropriate number of significant figures
Formula
Data
(a)
C1V1 = C2V2
C1 = 1.2 g/L, V1 = 5 mL, V2 = 250 mL
(b)
PV = nRT
P = 1.024 x 105, V = 0.234, R = 8.314, T =
298.2
(c)
Tc = 0.556 (Tf – 32)
Tf = 213.3
(d)
(e)
C
8000 (b  2a)
V
C1V1 = C2V2
b = 65.2, a = 21.3, V = 10.0
C1 = 1000 mg/L, C2 = 50 mg/L, V2 = 250 mL
64