Download Chemistry 11 Lab booklet # ___

Chemistry 11
Lab booklet # ___
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Some Standard Diagnostic Tests
SUBSTANCE
TESTED
DIAGNOSTIC TEST
water
f cobalt(II) chloride paper is exposed to a liquid or vapor, and
paper turns from blue to pink, then water is likely present.
Oxygen
If a glowing splint is inserted into the test tube, and the splint
glows brighter or relights, then oxygen is likely present.
hydrogen
If a flame is inserted into the top of the test tube, and a squeal
or pop is heard, then hydrogen is likely present.
carbon dioxide
halogens
If the unknown gas is bubbled into a limewater (calcium hydroxide)
solution, and the limewater turns cloudy, then carbon dioxide is
likely present.
If a few mL of an organic liquid such as hexane, or a chlorinated
hydrocarbon is added, with shaking, to a solution in a test tube,
and the color of the solvent appears to be
- very pale yellowish, then chlorine is likely present.
- orange, then bromine is likely present
-purple, then iodine is likely present
free iodine
If a solution forms a blue-black coloration in contact with starch
or a starch solution, then free iodine is present.
Acid
If a liquid contacts red and blue litmus paper, and the blue
litmus turns red, then an acid is present.
Base
If a liquid contacts red and blue litmus paper, and the red litmus
turns blue, then a base is present.
Neutral
If a liquid has no effect on both red and blue litmus paper, then
only neutral substances are likely present.
ionic solution
If a solution is tested for electrical conductivity with a
conductivity test device, and the solution conducts a current,then an ionic
substance is present, or a molecular substance whichionizes in solution is
present.
Ionizing molecular substance
If a molecular substance is tested for electrical conductivity with a conductivity test device,
and the solution conducts current then a molecular substance which ionizes in solution is
likely present.
There are thousands of diagnostic tests. You may discover more of these.
Laboratory Work
PRELAB PREPARATION:
- Required to show evidence of pre-lab preparation. If insufficient, student is
not allowed to do the experiment, and mark is zero.
TYPES OF LABS:
exercise / activities / experiments
PAGE 1 – DATA SHEET
- done by each student
- shows pre-lab assignment, from lab sheet hand-out
- in ink on standard loose leaf paper
**contains original copy of data; filled in during the lab.
Science works with original data. What you get is what you pass in. If it is
recopied for neatness, the original must also be attached behind the copied
data sheet.
- write on reverse side of paper if needed
- Remember Page 1 of Laboratory Report is important, attach to the back of the
report if made a recopied Page 1. Pre-lab work must be completed for a
ticket into the lab.
Page 1 - Example
Lab #
Data date
Title
Due date
Your name
Partner’s name
Problem:
Prediction:
Experimental design:
(The boxes marked on the lab will indicate
Materials:
which sections to include in report)
Experimental procedure:
Data: Recorded qualitative, descriptive observation either in outline form or table
form, as directed. Record quantitative data in table form.
PAGE 2 – PROCESSING THE DATA
- in ink on standard loose leaf paper
- contains such things as calculations, graphs, interpretations, conclusions,
assessment.
- groups are working together but should not copy work. Have your own
opinions and words please.
Analysis- Answer questions and/or do calculations, as directed.
Calculations are presented in formal step format.
Written parts are in formal English using past tense, passive voice: no personal
pronouns.
Conclusion:
State what was found about the Problem, and basis for this from
the experiment.
Evaluation: - evaluates accuracy and precision
- critiques the experimental design as to possible sources of error
- examines assumptions
- may critique the authority used in making Prediction
Lab report policies:
- Deduction of 20% for each day late.
- If having difficulty, pass report in “as is” on due date and ask for a rewrite after report is
returned.
- If absent on due date, pass in report first day back, informing instructor
NOTE: Mark is zero for reports passed in after an experiment has been marked and
returned to students.
NOTE: Failure to submit a report bars the student from doing the next lab, with resulting
mark of zero.
REWRITES
- Rewrites for a maximum mark of 16/20 may be requested on an individual basis
by those who pass in report on due date. Make an appointment
MAKEUPS
- Makeup experiments may be done if absent on lab day for an excusable reason. It
is the student’s responsibility to follow up on missed labs. Make-ups must be done
within two weeks of the miss. Students must be available to do make-ups at
announced times after school.
COMPULSORY FINAL LAB REPORT BOOK
- Save all reports; these are submitted in the form of a lab report book at the end of
the course for final grading in the portfolio. Must create a title page for this section
and a detailed table of contents. Labs should be corrected before being placed in the
portfolio. This is very important because they are used to study for the final lab
exam.
Pre-Lab Readiness: Need a ticket
Students are required to show evidence of pre-lab work. If insufficient,
student is not allowed to do the experiment, and the mark is 0.
Goggles:
Do not put knots in the goggles, which must be worn at all times.
Do not set up in front of the sink because you need access for washing
Lab Techniques:
Scoopula:
- hold in fingers securely like a fork, between thumb and index
finger.
- Pick up bottle with free hand
- hold scoopula and bottle horizontal to collect sample
- only fill the beveled end; samples do not like to fall off
- tapping to discard extra sample back into bottle
Notice: Only use the scoopula for a single sample.
Placing sample into test tube: Scoopula – Using paper is similar
1) pick up test tube into free hand
2) hold both horizontal
3) place scoopula into test tube
4) samples like to go directly to the bottom; do not let roll off
5) tilt quickly to vertical position
6) test tube racks should have pegs behind, not in front.
7) Remember, you do not want anything in your way.
Weighing paper to test tube / beaker:
1) carry carefully back to station
2) gently fold the paper
3) place close to test tube top
4) turn to vertical position
5) tap paper with finger to get all of sample desired
**Weighing paper is like toilet paper; you never want to use it twice for obvious reasons.
_____________________________________________________________
Using the electronic balance:
1) reset to 0 2) place on weighing paper 3) reset 0 so that this weight in not used
4) use scoopula following above steps to get sample (Scoopula technique)
5) tap the sample onto the weighing paper with the free hand;
6) do not dump on all at once. You may have too much.
Notice: Lab paper will tell you if you require exact amounts or about a certain amount. Do not
waste valuable time trying to get exact amounts if it is not required.
5 g vs 5.0 g 5g is between 4g and 6g while 5.0 g is an exact quantity
_____________________________________________________________
Checking for odor:
- gently fan fumes to the nose with the free hand
______________________________________________________________________________
Testing for hot to touch
after letting cool bring finger slightly close; feel for heat and then bring
sligthly closer.
Pouring out of a Reagent bottle:
- should bend knees to be eye level with target
- pour away from the label on the bottle so that we do not ruin the
label and then be unable to identify what is in the bottle
Special bottle with stopper top:
- place palm up and use index and middle finger
- keep in hand while holding onto the bottle
- pour away from label
Bunsen Burner:
When apart, you can easily see the tiny pinhole, air control as the propane rises to mix with air at
top to ignite. The steps:
1) make sure both fittings are snug
2) half open the air adjustment
3) adjust flame using air control; do not put fingers over the hole
4) if noise too much air, limit orange flame 5) hot spot just above top of the light blue
@ Propane is off at 90 degrees to the spout
Lighting:
1) arms length away 2) head back
3) if it does not light on 2 to 3 seconds, turn off the propane and wait for it to diffuse away
4) if you hear a few scratches of the lighter, then it was too long.
Holding the burner:
-
hold with the ends of the 5 fingers on the base and not the hose or hot spots.
Gentle Heating:
1) keep head away from flame 2) start at a distance
3) circle motion
4) bring closer 5) you do not want to break the glass
6) unless otherwise directed, stop heating when no more change in occuring
Ring stand and Clamps:
1) short side to you for balance
2 ) test tube clamp has 3 functions@ Make sure all 3 are tight
a) up and down b) swivel C) test tube holder away from flame
_____________________________________________________________
Contamination Summary:
- Will be a separate scoopula present to collect
- Top to bottles: face up on the counter top; very dirty sometimes
- Bottle tops back on as soon as you have collected the sample
- Nothing in the lab should touch the dirty countertop. Everything, ex. pipette
dropper, should have a landing pod to land on to prevent contamination. Paper
towel is good
- Do not return samples to supply bottles if you measured out too much. Only
do this if there is a separate scoopula designated for a sample
Clean up the Lab!
Everything should be rinsed or placed in dry disposal
We use a powerful cleaner; do not waste. Only require a few drops
First: Make soapy water in your largest beaker. 400ml
Wash inside and outside using brushes on the table
Test tubes a handful at a time; wash vigorously
Wash each handful all at once; rinse all at once
Wash beakers and other material and rinse
They will air dry; let most water drip off first, place in proper location
Dropper Pipette- suck up water, pull off rubber, rinse each out; put back
together
Use the entire extra paper towel from the landing pads to wipe up excess
water after all the instruments are returned to the proper spot in the
student drawers.
Anything picked up from the front of the lab should also be brought back to the
spot where you found it.
Laboratory Safety Guidelines
Middleton Regional High School
General Safety Guidelines
1. Always be safety-conscious. Move about the laboratory in a safe
manner.
2. Report all accidents. No accident is too small to report.
3. Know the locations of safety equipment in the laboratory; use only in
emergencies. Know the location of fire exits.
4. Plan ahead. Become familiar with all of the health and safety hazards
of equipment and chemicals in use. If you are not sure, ask.
5. Safety glasses (splash proof goggles) must be worn while working with
any chemical.
6. Use Bunsen burners only at the direction of the teacher. Open flames
are prohibited when flammable substances are in use in the laboratory.
Never leave active burners unattended.
7. Confine long hair while working in the laboratory; watch for flames and
machinery.
8. Always wash your hands thoroughly at the end of the laboratory period.
When handling chemicals, keep your hand away from your face, eyes,
and body, until they have been washed.
9. If a chemical is splashed or spilled on your skin, flush it away with
plenty of water. If irritation or pain develops, report it immediately.
10. If you should get chemicals into your eyes, go directly to the eyewash
fountain and gently flush with water. Report this immediately to you
teacher.
11. Do not consume food or water while in the laboratory; never taste
chemicals.
12. Keep desk clear of all books, clothing, and other personal property
except necessary lab directions and notebooks.
13. Returned cleaned equipment to its proper place when finished. Report
any damage of equipment to the instructor.
14. Keep sinks clean and free of glassware.
15. Never return chemicals to stock bottles.
16. Handle only materials that you are assigned to work with.
17. Use acids and bases with caution. Wipe up spilled materials at the
direction of the teacher. Watch out for eyes, skin, and clothing.
18. Keep reagent bottles covered. Follow the correct procedure for opening
reagent bottles.
19. Do not use unlabelled chemicals. Check label twice to be sure that you
have the right bottle. Refer unlabelled containers to your teacher.
20. Follow all instructions, both written and verbal. If you think some
changes in procedure are necessary or desirable, check with your
teacher.
Broken Glassware
1. Broken glass – clean up immediately with brush and pan.
2. Before inserting (or removing) glass tubing or thermometers
into corks or stoppers check with your teacher for proper
procedure.
Avoiding Burns
1. Keep a lighted burner away from clothing, books, or other
combustibles. Lean away from top of Bunsen burner while it
is being lt.
2. Hot glass looks just like cold glass. Use care when touching
glass objects that have been heated.
3. To heat easily evaporated (volatile) flammable liquids, use a
water bath, inside a fume hood if possible.
4. Do not heat anything inside a closed container.
Handling Chemicals
1. To smell the contents of a container, use a “wafting” action of
the hand as demonstrated by your teacher.
2. Use care to avoid splattering of solution when heating to
dryness.
3. Never use mouth for pipetting up poisons, corrosive liquids,
organic solvents, live cultures, or contaminated materials.
4. Always add acids to water slowly, carefully, and with gentle
stirring (solid glass rod only). This should generally be done
in a large open beaker. Avoid over-heating that often
accompanies too rapid mixing.
ACID INTO WATER…never the reverse.
EXPERIMENT:
Problem:
PHYSICAL AND CHEMICAL PROPERTIES
M8896
To determine whether properties are physical or chemical in the following:
a. when copper(II) sulfate is heated
b. when zinc oxide is heated
c. when solid iodine is heated
d. when sodium thiosulfate solution is mixed with
hydrochloric acid
Prediction:
When substances are heated or mixed together their behaviors may be physcial, or
chemical. Physical properties are ones that can be determined without changing the
composition of a substance. Chemical properties are those that can be determined only
when a chemical change occurs. Prior knowledge of chemical properties is needed to
make a prediction as to what will happen.
Experimental design:
Samples of the substances are treated as in the experimental procedure. Deciding
the type of property (physical or chemical) is attempted from the evidence gathered.
Experimental procedure:
a.
Using proper lab burner technique heat 0.25 g of blue copper(II) sulfate crystals
in a dry 150 mm test tube. Heat until no further change is observed. To gain
evidence about whether what occurs is a physical or chemical property of copper(II)
sulfate, allow the test tube to cool to room temperature, and add a couple of drops of
water one at a time to the material in the tube.
b.
Place about 0.25 g of zinc oxide in a 150 mm test tube and heat until you observe a
change. Allow it to cool for 1 min and observe.
c.
Place 1 crystal of iodine (to be distributed by the instructor) in a dry 150 mm
beaker. Place a watch glass over this beaker and add an ice cube to the watch glass.
Support the beaker on a wire gauze on an iron ring and heat under control with the
burner until the iodine crystal dissappears. Allow to cool. Then scrape off any
material on the bottom of the watch glass, and perform the diagnostic test for iodine
using hexane.
d.
Add 5 mL of 0.5 mol/L sodium thiosulfate to a test tube containing 5 mL of 2 mol/L
hydrochloric acid.
CLEANUP: Discard solids in the solid disposal container. Other material can be rinsed
and washed with detergent & water.
EXPERIMENT:
PHYSICAL AND CHEMICAL PROPERTIES page 2
Data:
A copper(II) sulfate crystals before heating
changes in tube during heating
material in tube after cooling
changes on adding drops of water
B zinc oxide before heating
changes in tube on heating
observation on letting tube cool
c. iodine crystal before heating
changes during heating
material on bottom of watch glass
changes with material and hexane
d. 0.5 mol/L sodium sulfate
2 mol/L hydrochloric acid
observation on mixing liquids
Analysis/Conclusion:
Fill in and complete the data table listed below
Part
A
B
C
D
Type of property
(physical, chemical,
inconclusive)
Reason
Conclusion:
Which observations were physical properties and which observations were chemical
properties.
Evaluation:
a) Answer these 2 questions
1. Did this experiment prove physical and chemical properties easy/difficult to
identify? Explain in a sentence or two.
2.
Is a color change a conclusive test for establishing whether a physical or chemical
change has occurred?
b) List and briefly discuss sources of error for this lab activity.
M97
EVIDENCE OF CHEMICAL REACTIONS
Problem: To investigate what evidence, if any, shows that a chemical change has
occurred when the following substances are mixed:
1.A zinc strip is momentarily placed into a hydrochloric acid solution.
2.A couple of drops of blue bromthymol blue solution are added to
hydrochloric acid.
3.A few drops of silver nitrate solution are added to hydrochloric acid.
4.Hydrochloric acid is added to sodium hydrogen carbonate (sodium
bicarbonate) solution .
5.Ammonium nitrate crystals are stirred into water.
6. Hydrochloric acid is added to sodium acetate solution.
7.A couple of drops of phenolphthalein solution are added to an ammonia
solution.
8.Sodium hydroxide solution is added to cobalt(II) chloride solution.
9.Sodium nitrate solution is added to potassium chloride solution.
10.A copper wire is place in a silver nitrate solution.
Prediction:
List from page 15 of the text all the evidences of chemical reaction.
Experimental design:
In each part two chemical are brought in contact, and if a change occurs it is
assumed to be a chemical change that happens rapidly at room temperature.
Procedure:
1. Combine the substances according to the instructions provided at each station,
and record all observations before, during, and after the mixing.Þ
2.Clean all apparatus and the laboratory table area, and dispose of used chemicals
as directed by the instructor, before proceeding to the next station.
Data: A three step process
It is very important to have detailed observations of all the chemicals before the reaction
and significant observations during the reaction. Use the 4 senses.
Sample:
Chemical 1 before reaction
Chemical 2 before reaction
Reaction after mixing
Part 2 – Working with the Data
Analysis –
You must comment on all the evidences of chemical reactions shown during
this activity. In this part of the write up, you must state the sign of chemical
change along with proof of this evidence from the lab. Use an example or two
from the lab that shows the sign of chemical change in action.
ConclusionList all the different signs of chemical change but there is no need to state
evidence like in the analysis.
Evaluation:
a) Sources of possible errors
b) Comment on the experimental design of the lab and suggest
improvements to the lab.
Extension:
For each situation, state if the change was physical or chemical and give proof
to support your answer.
a) a rusting pop can
b) mixing red koolaid and water
c) 2 solutions are mixed together to give a blue chunky solid at the bottom
of the test tube, with a clear solution resting on top
d) Cutting the grass
e) Dropping a medicine tablet into water produces many bubbles that leave
the solution.
EXERCISE:
Procedure:
FORMULAS AND IONIC CHARGES
1. Prepare a table as shown below.
2. You will be given a sheet with "ion" squares.
3. Construct formulas of the combinations given in the table.
4. Write the chemical name of the compound in the "Name of Substance"
column.
Predict the formulas for five additional compounds
using ions listed in this
Combining substances
Laying out
the ions
Chemical Formula
aluminum + bromine
sodium + oxygen
iron(II) + sulfur
aluminum + nitrate
ion
iron(III) + chlorine
aluminum + oxygen
potassium + sulfate
ion
ammonium ion +
sulfur
iron(III) + sulfate
ion
sodium + phosphate
ion
Use ions provided to create 5 new compounds
Name of
Substance
Ion Dice
Data table #2
Combining substances
Chemical formula
Chemical name
Questions:
1. What name is given to the compounds composed of just 2
elements?
2. When iron rusts, it combined with oxygen in the air. Using
your ions, predict the 2 different compounds that could be
produced.
3. State a general rule for how charges are used to write
formlas
Extension:
Write chemical formula
a. zinc choride
Write the chemical name:
a. Pb3PO4)2
b. lead (iv) oxide
b. Cr2O3
c. silver bromide
c. Bi2(SO4)3
d. sodium phosphate
d. RbNO3
e. magnesium sulphide
e. HgI2
f. colbalt (ii) fluoride
f. AgNO3
g. barium oxide
h. calcium phosphide
g. CuSO4
Types of chemical reactions
Problem: To observe and identify some different types of reactions.
Background: List five types of simple reactions and write a chemical
equation as an example of each type.
Experimental procedure:
A. Place 5 mL of sodium sulfate solution in a test tube. Dropwise add
a medicine dropper full of barium chloride solution. DISCARD DOWN
SINK WITH RUNNING WATER.
B. Using tongs hold a 5 cm piece of clean, shiny copper wire (cleaned
with steel wool or sandpaper) in a burner flame. When no further
change is apparent, remove it and examine it. It is okay to scrape
the wire with a spatula. DISCARD IN SOLID WASTE TRAY.
C. Using tongs or tweezers place a single, small piece of calcium metal
in a dry test tube. Add 5 mL of water. DISCARD DOWN SINK WITH
RUNNING WATER. Place splint in water.
D. Place 5 mL of 6% hydrogen peroxide solution in a test tube. Add a
few grains of manganese dioxide. When the reaction in the tube is
going vigorously insert a glowing splint into the mouth of the tube.
Hint: manganese dioxide is a catalyst here. Also, water is one of
the products in this reaction. DISCARD IN SINK WITH RUNNING WATER.
E. Place a clean iron nail in a test tube and add copper(II) sulfate
solution so as to come about halfway up the nail. After several
minutes remove the nail and examine it. It is okay to scrape the nail
with a spatula. DISCARD NAIL IN SOLID WASTE TRAY AND THE LIQUID
DOWN THE SINK WITH RUNNING WATER.
Data:
Reactants
A. sodium sulfate/ barium chloride
B. copper + oxygen
C. calcium + water
D. hydrogen peroxide
manganese dioxide
E. iron
copper(II) sulfate
Reaction/products
Questions:
a. Write balanced chemical equations for all reactions identified. Write
the chemical name of each substance below its formula or symbol.
State the type of reaction. The second product may not always be
apparent but use the types of reactions rules and other observations to
determine all the products produced
b. In which part was the type of reactions easiest to determine? Reason?
c. In which part was the type of reaction most difficult to determine?
Reason?
Extension:
a) Bubbles of hydrogen gas and aqueous iron (iii) chloride are produced
when iron is placed into hydrochloric acid
b) Solid silver oxide can be heated to give silver and oxygen gas.
c) Solid tetraphororous decoxide reacts with water to produce phosphoric
acid.
EXPERIMENT:
PRECIPITATES AND EQUATIONS
Problem: To investigate the formation of precipitates by double displacement reactions
and note some characteristics of precipitates.
Prediction:
A precipitate is an insoluble solid produced in a chemical reaction that occurs in
solution. In this experiment a series of double decomposition reactions are to be
carried out to see if a precipitate forms.
To make the prediction write the chemical equation for each anticipated
double displacement reaction and check solubility tables to see if one of the
possible products is insoluble. Indicate the predicted precipitate by writing
"(s)" after its formula in the equation. Also, write the name of each substance
below its formula in each equation.
Experimental procedure:
A. Dissolve a small quantity of iron(III) nitrate (about the size of a match head)
in distilled water in a 100 mm test tube. Use the smallest amount of water possible.
Shake vigorously. NOTE: ”CLEAR SOLUTIONS ARE NEEDED. IF UNABLE TO GET
A CLEAR SOLUTION, LET THE SOLID SETTLE AND DECANT OFF CLEAR
SOLUTION INTO ANOTHER TEST TUBE, AND USE THIS FOR THE REACTION.
In a second test tube place a matching volume of
0.1 M sodium hydroxide solution. Mix the solutions in the first tube, and observe.
B. Repeat part A using iron(II) sulfate in place of the iron(III) nitrate.
C. Repeat part A using copper(II) sulfate in place of the iron(III) nitrate.
D. Dissolve a similar small quantity of sodium phosphate in distilled water in a
test tube. Use the smallest amount of water possible. In another test tube place a
matching volume of cobalt(II) nitrate solution. Mix the solutions in one of the tube,
and observe.
E. Dissolve small quantities of lead (ii) nitrate and potassium iodide in distilled
water in separate test tubes. Use the smallest amount of water possible in each case.
Mix the two solutions and observe.
Data:
Part Reactant #1
A
Fe(NO3)3(s)
Fe(NO3)3 (aq)
(give formula & description)
B
C
D
E
Reactant #2
NaOH(aq)
After mixing
Analysis/Conclusions:
a) Include a statement or two about characteristics of precipitates
observed in this experiment. Give proof and evidence from the
lab
b) Using the lab and class notes; give characteristics of double
replacement reactions
Extension:
a) BaCl2 (aq) + H3PO4 (aq)
b) Fe(NO3)3 (aq) + LiOH (aq)
c) A solution of calcium iodide is poured into a solution of mercury (ii)
nitrate.
d) Solutions of potassium fluoride and calcium nitrate are mixed
EXPERIMENT
ANALYSIS OF A CHEMICAL REACTION
Problem: To use qualitative and quantitative evidence to determine which of the
following reactions occurs when sodium hydrogen carbonate is heated:
1.
NaHCO3(s) ----> NaOH(s) + CO2(g)
2.
2NaHCO3(s) -----> Na2CO2 (s) + CO2(g) + H2O(g)
3.
2NaHCO3(s) ------> Na2O(s) + 2CO2(g) + H2O(g)
4.
4NaHCO3(s) -----> 2Na2C2O4(s) + O2(g) + 2H2O(g)
Prediction:
To make a prediction, for each of the contending equations compute the theoretical
ratio: equation mass NaHCO½3/equation mass solid product. [In the Analysis/Conclusion
to argue which of the reactions actually occurs compare this theoretical ratio with
the actual ratio: experimental mass NaHCO½3/experimental mass solid product.]
Experimental design:
A known mass of sodium hydrogen carbonate is heated and the mass of solid
residueis found. This solid is assumed to be one of the four solid products in the competing
equations. All other products are gaseous and are assumed to be driven off in heating.
Qualitative diagnostic tests for carbon dioxide and for water are used to eliminate
some of the contending equations.
Experimental procedure:
1.
QUALITATIVE INVESTIGATION: Place about 0.5 g of sodium hydrogen carbonate in a
150 mm test tube. Clamp the test tube to a ring stand as demonstrated by the
instructor. Heat the tube with a burner gently then more strongly. Use a 150 mm test
tube 1/4 filled with limewater held to the mouth of the heated test tube to perform
the diagnostic test for carbon dioxide. Also examine the test tube containing the
sodium hydrogen carbonate for other products, and perform other diagnostic tests as
needed. Record qualitative observations.
2. QUANTITATIVE INVESTIGATION: Mass a clean, dry crucible and cover. Add about 1.5 g of
NaHCO3 to the crucible and determine the mass of the crucible, cover, and solid to 0.01g or 0.001
g. depending on the readability of the balance used.
Place the crucible, with its cover slightly ajar, on a clay triangle on a ring
stand. Heat gently for one minute, then strongly for five minutes.
Place the crucible and cover on the base of a ring stand and allow them to cool to
room temperature. Then mass the crucible, cover, and solid.
Option: Re-heat to constant mass.
Data: (QUANTITATIVE)
mass of crucible and cover
mass of crucible, cover and NaHCO½3
mass of crucible, cover, and residue after heating
=
=
=
Analysis/Conclusion:
[Use qualitative evidence to eliminate one or more of the contending equations, if
possible. Quantitative arguments can be made using the idea given in the Prediction
above]
Note: The above is background information for the lab.
Lab Prep – Set up a page as the following
Analysis of a Chemical Reaction:
Problem: To use qualitative and quantitative evidence to determine
which of the following reactions occurs when heating Sodium
Hydrogen Carbonate.
1.
2.
3.
4.
NaHCO3(s) --Æ NaOH(s) + CO2(g)
2 NaHCO3(s) --Æ Na2CO3(s) + CO2(g) + H2O(g)
2NaHCO3(s) --Æ Na2O(s) + 2CO2(g) + H2O (g)
4NaHCO3(s) --Æ 2Na2C2O4 (g) + O2(g) + 2H2O (g)
Prediction: Quantitative investigation.
Equation mass NaHCO3
Equation mass solid mass product
Equation 1:
Equation 2:
Equation 3:
Equation 4:
1) What is the diagnostic test for carbon dioxide? (From 1st lab handout)
2)
What is the diagnostic test for water?
Data Table: Part1 (Observations)
Data Table: Part 2
Mass of Crucible and cover
Mass of crucible, cover and contents
Mass of crucible, cover and residue after heating
=
=
=
Analysis/Conclusion:
Show calculation of the residue after heating. Mass used
=
Mass remaining
Eliminating contending equations.
Use both quantitative and qualitative data to arrive at the reaction you actually see
happening in the lab. Equation that we know is happening in demonstration:
1.
2.
3.
4.
NaHCO3(s) --Æ NaOH(s) + CO2(g)
2 NaHCO3(s) --Æ Na2CO3(s) + CO2(g) + H2O(g)
2NaHCO3(s) --Æ Na2O(s) + 2CO2(g) + H2O (g)
4NaHCO3(s) --Æ 2Na2C2O4 (g) + O2(g) + 2H2O (g)
EXPERIMENT PROPERTIES OF TWO TYPES OF SOLIDS M9196
Problem:
To determine how an ionic solid and a molecular solid compare as to
volatility, hardness, melting point, solubility in water, and solubility in 2-propanol.
Prediction:
[Consider forces (bonds) between the types of particles in each type of solid.]
Experimental design:
Sodium chloride is used as a representative of ionic solids. Camphor, an organic
compound, is used as being representative of molecular solids. Simple examinations
are performed to check on the properties named in the Problem. Regarding solubility,
water is an inorganic solvent, and 2-propanol is an organic solvent.
Experimental procedure:
1. On two pieces of weighing paper place separate 0.2 g samples of sodium chloride
and camphor. Examine each solid for odor.
2. Rub a small sample of each solid between the fingers to check on hardness. Also
check by attempting to crush a few small crystals of each solid between a spatula and
watch glass.
3. Place a few crystals of each solid side by side in separate piles on an inverted
crucible cover. Support the crucible cover on a clay triangle on an iron ring. Heat
GENTLY until one of the two solids melts. Then heat more strongly for a minute or
two. (The molten solid may catch fire. Let it burn out.)
4.Divide the remaining crystals of sodium chloride evenly between two 100 mm test
tubes. Also, divide the remaining camphor evenly between two 100 mm test tubes.
Add 3 mL of water to each separate solid and shake vigorously.
Add 3 mL of 2-propanol (isopropyl alcohol) to each separate solid, and shake.
DISPOSAL: Solids go in solid waste container, liquids down the sink in running water.
Data:
Physical property
Odor
(volatile, nonvolatile)
Hardness
(hard, soft)
melting point
(high, low)
Solubility in water
(soluble, insoluble)
Solubility in 2-propanol
(soluble, insoluble)
sodium chloride
camphor
Note:
The data in this table will be collected while watching demonstrations. It
will help you with your analysis questions.
“Do you know everything about molecular and ionic compounds”?
Chemical
Name
Chemical
formula
Class of
State a
compound Room
temp.
Solibility
in water
Solution
color
Electrical
conductivity
H2O
KMnO4
C3H8
C12H22O11
NaCl
CuSO4
C2H5OH
NaHCO3
CaSO4
Analysis / Conclusion:
Using all the information collected in this lab and all background class
information, students must develop their own empirical definition of the
two compounds. A chart can be used. A paragraph for each can be used.
I NEED ALL THE DETAILS PLEASE!
EXERCISE:
COVALENT MOLECULES
Directions:
For each molecule assemble the model and fill in the across the Table for that
molecule, before going on to the next one. For single bonds use inflexible connectors. For
double and triple bonds use the longer, more pliable connectors (care not to damage these,
as they are made of soft plastic, also replacements are difficult to obtain.)
Data: (Instructions for what goes in each column are noted inside each column.)
Molecular
formula
Shape of
molecule
Electronegativity
difference
Bond type
Kind of
molecule
Electron Dot
Diagram
H2
Cl2
O2
N2
HCl
CO2
H2S
NH3
CH4
CCl4
CHCl3
C2N2
H2CO
HCN
H2N2
Questions:
1. What features of molecules did the models more or less accurately portray?
2. State any limitations in the models used.
3. Give any recommendations for improving the m
Extension:
CF4
CS2
1. Write the electron dot formula for the molecule.
2. How many electron pairs around the central atom?
3. What is the preferred angle of separation about the central atom?
4. How many nonbonding pairs around the central atom?
5. Predict the bond angle .
6. State the bonds in the molecule.
7. Using the electronegativity table, calculate the ED in the
molecule.
8. Name the type of bond(s) in each case.
9. Is the molecule polar or nonpolar?
10. Draw the Lewis structure of the molecule.
Formula
Shape
ED
Bond type
Kind of
Electron
molecule Dot formla
H2
Cl2
O2
N2
HCl
CO2
H2 S
Formula
Shape
ED
Bond type
Kind of
Electron
molecule Dot formla
NH3
CH4
CCl4
CHCl3
C2N2
H2CO
HCN
H2N2
Activity
Mass and Moles
Introduction:
Samples of solids are provided in containers beside balances. Students must calculate the
mass and chemical amount (moles) of each solid. (The mass of the empty container is
given in each case.) The calculated moles of solid is compared with the actual
number of moles so as to assess the accuracy and precision of the work done.
Rules for recording and calculating using significant figures are followed.
Data Table:
substance 1
substance 2
substance 3
name of substance
formula of substance
mass of container &
contents (g)
mass of empty container
(given) (g)
mass of substance (g)
Molar Mass (g/mol)
chemical amount of
substance
(in mol)
Number of representative
particles (particles)
Calculations:
Present the following calculations for each substance in a separate block.
Adhere to the rules for calculations using significant figures.
1.
Show formal presentation of calculation of mass of solid.
2.
Show formal presentation of calculation of molar mass
3.
Show formal presentation of calculation of chemical amount of solid.
4.
Show formal presentation of calculation of the number of representative particles
Extension:
Using the Mole wheel! Complete the following table. Showing all work and
adhering to significant digit rules!!
Formula
H2S
NO2
O2
CH4
Name
Moles
Mass (g)
Volume at
STP
Number of
Molecules
6.82
Nitrogen
1.50
dioxide gas
7.35
Methane
3.6 x 1022
EXPERIMENT:
EMPIRICAL FORMULA
M859296
Problem: To determine the empirical formula of a compound of magnesium and oxygen.
Experimental design:
A known mass of magnesium is heated so as to combine with oxygen in the air and
form an oxide of magnesium. Assuming the final solid consists of magnesium oxide
only, the mass of oxygen is taken to be the gain in mass. Any possible magnesiumnitrogen compound is assumed to be eliminated by treatment of the solid product with
water to form products that are driven off by heating.
Experimental procedure:
A. Determine the mass of a clean, dry crucible and cover. Use a balance that reads to
0.01 g or 0.001 g.
B. Cut a 30 cm piece of magnesium ribbon into two pieces of approximately equal
length. Roll each piece into a loose coil and place both coils in the bottom of
the crucible. Determine mass of the crucible, cover, and magnesium.
C. Place the covered crucible and contents on a triangle supported by an iron ring
clamped to a ring stand. The cover should be adjusted to that it is slightly ajar
to allow limited access of air.
D. Heat gently at first, then more strongly, to start the reaction and maintain it
such that it does not smoke. (If the reaction becomes too vigorous, close the cover
temporarily to slow it down.) Continue to heat until the magnesium appears
completely changed to a new substance. (Lift the cover periodically to check
progress.)
E. Remove the cover and heat strongly for five minutes. (If it smokes, put on the
cover and return to part D.) Allow to cool for three minutes.
F. To get rid of any possible magnesium nitride carefully add 10 drops of water to the
material in the crucible using a dropper. Make sure all of the solid is wetted.
Check for odour, and if there is an odour try to identify it by its familiarity and
consider the meaning of it being present.
G. Gently warm the crucible to evaporate the water without spattering. Cover the
crucible and heat strongly for 10 minutes, then allow to cool to room temperature.
Determine the mass of the crucible, cover, and oxide of magnesium.
H. Optional: Cover the crucible and heat strongly for 5 minutes, then allow to cool
to room temperature. Measure the mass of the crucible, cover and oxide of
magnesium. (This step is called "heating to constant mass", because if the mass
reading after the second heating closely agrees with the mass reading after the
first heating, the reaction is completel.)
Data:
mass of crucible and cover
=
mass of crucible, cover, & magnesium
=
mass of crucible, cover, & magnesium oxide =
Extension:
1) Calculate the empirical formula of the following
a. 11.66 g Fe and 5.01 g oxygen
b. 40.0% C, 6.7% H, 53.3% O %
2) Calculate the molecular formula of the following
a. If the empirical formula formula is NO2 and the molar mass of its molecular formula is
92.0 g /mol
b. Caffine; 49.5% C, 5.15% H, 28.9% N, 16.5 %O by mass, molar mass = 195.
Find the molecular formula
LAB
STOICHIOMETRY
M99
Problem: To compare the mass of metallic copper produced in a reaction with the mass
stoichiometrically possible, when excess aluminum reacts with 2.00 g copper
(II) chloride dihydrate.
Prediction:
Show the stoichiometric calculation of the mass of copper theoretically possible
when 2.00 g of CuCl2(H2 O)2 reacts with excess aluminum. Also, calculate the mass
of aluminum needed to react with this quantity of CuCl2(H2 O)2, so as to know how
much must be used to provide an excess of aluminum.
Experimental design:
A piece of aluminum foil (enough to provide excess aluminum) is placed in an
aqueous solution containing 2.00 g copper(II) chloride dihydrate. Aluminum replaces
copper in a single replacement reaction. The copper product is separated and its mass
measured. Note that the g/cm2 of aluminum foil will be given, so as to make it
possible to figure out how large a piece has to be cut off the roll.
Extension:
Show all your work
1) Copper wire reacts with silver nitrate solution to produce silver metal and a
solution of copper (11) nitrate solution. How many grams of metallic silver will be
produced when 2.37g of copper wire is reacted with excess silver nitrate?
2.Excess silver metal reacts with nitric acid to produce nitrogen dioxide, Silver nitrate
solution water. How many MOLES of HNO3 would be required to produce 5.00 of
AgNO3 (aq) ?
Stoichiometry Lab – Pre-lab preparation assignment
Problem – Copy from lab Sheet
Experimental Design – Copy from the lab Sheet. I know this is a
different order than on your lab sheet.
Prediction – The prediction for this lab consists of 3 parts
Part A: Write balanced chemical Equation for the reaction of
aluminum foil with copper(11) chloride dihydrate.
Part B: Use the equation to calculate mass of Copper theoretically
produced by the above reaction.
Aluminum is in excess.
Part C: Calculation of piece of foil to use. Therefore, this means the
amount of Al needed to react with the 2.00g CuCl2(H2O)2. Make sure that you
have enough in excess but we only want as little as possible to prevent errors.
Values needed:
2.00 g CuCl2 (H2O)2 used and is limiting reactant.
Yes, the extra H2O is used in molar mass calculation.
Calculation of mass of Al foil per cm3
Area = L x W
Mass = 11.24
100 cm x 30.3 cm
3.03 x 103 cm2
Therefore g / cm2
11.24g / 3.03 x 103 cm2
= 3.71 x 10-3 g / cm2 [ use this factor in part C]
Use to determine what size piece of aluminum must be used to be slightly in
excess during the chemical reaction.
Complete the lab prep on paper as usual. This time if will be collected before
the lab and passed back before the lab is conducted.
Lab Test Review
This is close to the last time you will use this review package. Please return in
good shape or pay $2.00.
Value: 10 % of final mark
There are no exemptions from the lab exam.
•Remember exemption conditions
Must pass the lab exam to qualify for an exemption.
Rational:
Students are responsible for all class labs and demonstrations during
the course.
This material has been collected throughout the term for section 1 of
the portfolio.
Lab introduction work:
1) Information on Lab write-ups done during the course introduction. (read)
2) Lab Techniques Handout (Important) A 2 page hand-out, describing
everything from using a scoopula, to proper washing techniques
3) WHMIS symbols (Not required)
4) Diagnostic tests sheet (Ones we did)
Lab: Chemical and Physical properties
Class notes: Notes and examples on physical and chemical properties
In this lab, students conducted 4 simple experiments, collected data, and had
to interpret the data
Students had to determine if properties were physical or chemical.
Know the difference between chemical and physical properties.
(Not chemical vs. physical changes)
•Heated copper(11) sulfate crystals
•Heated zinc oxide
•Heated Solid iodine and hexane test
•Mixed HCl and sodium thiosulfate
Lab: Evidence of chemical reactions
We did 10 station activities, looking for signs that something new was being
created. Know the evidences of chemical reactions and be able to able to
situations presented to you on the test.
•Be prepared to analyze data like you collected during this lab.•Based on the
data, students must determine if changes are chemical or physical
Lab: Formulas and ionic charges
•Class notes: Know entire chapter 5. •Know how to name chemical
compounds and how to write chemical formulas.•We used an activity to
balance an ionic compound to an overall charge of “O”. •On the exam test,
students will have to write a chemical formula and name chemical
compounds.
•A periodic table will be provided to determine the charge of monatomic ions
but the “polyatomic ions” should be mastered.
Lab: Types of chemical Reactions:
Lab focus:
1) Perform a chemical reaction
2) Be able to write products when given reactants, which you mixed together,
to create a balanced chemical equation.
A summary sheet similar to one given to you for this chapter 7 test will also be
given to you for this lab test.
Be sure to know the tips that indicate what type of reaction may be taking
place.
Example: Single replacement has 1 elements and 1 compound as reactants.
*Be able to write products when given reactants, producing a balanced
chemical equation.
Lab: Precipitates and equations:
Lab focus:1) Perform 5 double replacement reactions
2) Created our own solutions in some cases.
3) Be able to write the balanced equations and predict which is
-be familiar with data and the analysis from this lab.
-be able to discuss precipitates and double replacement reactions
Lab: Analysis of a chemical reaction (Activity)
Lab focus.
Using observations and mathematical calculations to determine which
chemical reactions occurs, when there is more than one possible scenario.
Lab: Mass and moles
During this lab, we calculated the mass of a compound located in a bottle.
From the mass, students were asked
- calculate moles (Use molar masses from periodic table)
- calculate representative particles (- Use Advogadro’s number•Study
the mole wheel in chapter 6.
Lab: Empirical formula
Be sure to know how to calculate an empirical formula, if given the
data (mass) like you gathered during the lab.
*
See master examples in class notes
1) Find mass, convert to moles first
2) Then divide by the lowest mole value to get the empirical
formula.
Lab: Stoichiometry
Lab focus:
1) Calculated a theoretical yield using a balanced chemical equation which
you created
2) Performed the lab following a detailed procedure and techniques you
should study for the test
3) Using a new filtration technique, students were able to calculate an actual
yield of copper
4) Using the theoretical yield and actual yield, students calculated the % yield
A) Could ask you to use the balanced equation to find the amount of a product
produced, theoretically. (Same as prediction in lab) B) Then calculate % yield
if an actual value is given to you as data. You would need to subtract numbers
to get the actual value.C) The lab procedure includes new techniques such as
filtration of filtrates. Know how to perform a stoichiometry lab of this type.
Lab: Covalent Compounds
Lab focus: (When given a formula)1)Draw ball and stick diagram
2)Use electron dot diagrams and VSEPR to determine shape and arrangement
of atoms
3)Calculate the ED
4)Predict the bond(s) type
5)Predict the polarity of the molecule
6)Draw the electron dot diagram
•Must be able to use your VSEPR theory notes to draw the electron dot
formula and to determine the shape of the molecule.
•Keep in mind we use electronegativites to predict bonds and polarity (Chart
will be given)
•**This question on the lab test may be similar to the analysis of a molecule
questions done with VSEPR theory in chapter 14. (Also on bonding test)
Lab: Properties of two types of solids
Lab focus:
1) A look at the properties of ionic and molecular compounds.
2) Explain the data collected by examining the forces present between each
the compounds
3) “Ionic force” vs. “Intermolecular force”
- The analysis of this lab is very important
-There is also much information in your class notes that can be used to
compare and contrast ionic and molecular compounds.
-Remember, the analysis wants you to completely compare and contrast these
two compounds and know why the differences and similarities exist.
Lab activity: empirical definitions of compounds
•This was an addition to the lab comparing ionic vs. molecular
compounds.•The data collected helped you to answer this question on the
previous lab.•“Completely compare and contrast ionic vs. molecular
compounds”-
Lab: Hydrocarbons
Be able to recognize the alkanes, alkenes and alkynes. Be able to draw their
structural formulas, carbon skeleton and also be able to name hydrocarbons
following the IUPAC naming system
Lab: Hydrocarbons
Almost the same as above
Except, this lab looks at isomers, cyclic compounds and the benzene ring.
Summing up the lab year:
1) Sources of error were a big part of our lab write ups and discussions
Any question about a lab could be asked, so be sure to re-read all the lab
sheets and procedures that were given to you so that you are familiar with all
aspects of the lab, not just the write up you passed in.
2) This lab test also provides an extra incentive to start to prepare for your final exam.
3) Start by organizing your information, creating study notes.
4) The
hardest part of the evaluation of chem. 11 is the following
•10 % - lab test
•15% - portfolio
•20% - final exam