Chem questions :)

Exploring Chemical and Physical Changes: Data Sheets, Post Lab Questions andnotes from Martha
➢ Make sure to read the lab handout and all Safety Instructions thoroughly before doing
the lab. Wear your gloves, safety goggles, and lab apron at all times while conducting
the lab.
➢ You are working with toxic chemicals for this lab. You should not eat, drink, chew gum,
or do this lab around children. Make sure to do this lab away from an area where you
have food, and thoroughly clean the area once you are finished.
➢ This lab really will take you about 3 hours to do it carefully and correctly.
➢ You MUST use the chart I have provided NOT the chart that came with the lab handout.
➢ Make sure you write complete observations. Merely saying “clear” for a description will
not get you a good grade. I do not know what you are calling clear, I don’t know what
color it is, nor do I know if it is a clear solid, liquid or gas.
➢ The test tube rack is a bit flimsy, so I had something heavy behind it so it couldn’t fall
over. This is especially true when you are taking the temperature of you reagents.
➢ For Activity 2 the materials will over flow your test tube. To avoid this, I did the activity
in one of the medicine cups.
➢ If your reagent, such as the phenolphthalein, is in a dropper bottle you don’t need to
use a pipet. You can just squeeze the amount needed out of the dropper bottle.
➢ For some of the activities you use the product of the previous activity, so be careful to
not dump anything in your waste container until you are sure that you won’t need it
again.
➢ HAVE FUN!!!!!
Exploring Chemical and Physical Changes: Data Table
Activity
1
2
3
4a
4b
Appearance of
Reagents before
mixing
Appearance of
Reagents after
mixing
Initial Final
Temp. Temp.
oC
oC
Type of
Change
Physical
or
Chemical
Evidence for a
Chemical Change
Type of
Reaction
Redox
Acid-Base
ppt
Activity
5
6a
6b
9
10
Appearance of
Reagents before
mixing
Appearance of
Reagents after
mixing
Initial Final
Temp. Temp.
oC
oC
Type of
Change
Physical
or
Chemical
Evidence for a
Chemical Change
Type of
Reaction
Redox
Acid-Base
ppt
Activity
11
12
Appearance of
Reagents before
mixing
Appearance of
Reagents after
mixing
Initial Final
Temp. Temp.
oC
oC
Type of
Change
Physical
or
Chemical
Evidence for a
Chemical Change
Type of
Reaction
Redox
Acid-Base
ppt
POST-LAB QUESTIONS (Type in your answers to the questions below)
1. In Activity 1 how would the amount of NaCl produced be affected (more, less, remain the
same) if instead of adding 2 mL of 1 M Na2CO3 you added 4 mL. Explain.
2. In Activity 6 how would the amount of NaCl produced be affected (more, less, remain the
same) if instead of adding 2 mL of 1 M HCl you added 4 mL. Explain.
3. Consider the pictures below. These pictures represent 1.0 L solutions of 1.0 M NaCl(aq)and
1.0 M MgCl2(aq). The representations of the ions in solution are the correct relative amounts.
Water molecules have been omitted for clarity. Correctly label each of the beakers and provide
a key to help identify the ions. Keep in mind that the pictures represent the relative amounts of
ions in the solution, and answer the following questions.
a. What is the concentration of
chloride ions in each beaker?
b. Explain how it is that the concentrations of chloride ions in these beakers are different
even though the concentrations of each substance are the same, 1M.
c. Say you were to dump out half of the MgCl2 solution from the beaker above. What would
the concentration of the MgCl2 in the remaining solution?
4. Write an equation for the following reactions, balance each, and give the reaction type.
a. solid potassium and oxygen gas react to form potassium oxide.
b. Silver nitrate and sodium chloride react to form silver chloride and sodium nitrate.
c. iron and oxygen gas react to form iron (III) oxide.
d. Nitric acid and barium hydroxide react to form liquid water and an ionic compound.
CHEMISTRY
Exploring Chemical and
Physical Changes
Investigation
Manual
EXPLORING CHEMICAL AND PHYSICAL CHANGES
Table of Contents
2
Overview
2
Objectives
2
Time Requirements
3
Background
4
Materials
5
Safety
6
Preparation
7
Activity 1
7
Activity 2
7
Activity 3
8
Activity 4
8
Activity 5
9
Activity 6
9
Activity 7
10 Activity 8
10 Activity 9
10 Activity 10
11 Activity 11
11 Activity 12
11 Disposal and Cleanup
12 Data Table
Overview
In this investigation, a series of laboratory activities that feature
physical or chemical changes are performed. Differences in chemical and physical changes are explored and discussed. The type
of change that is occurring is identified based on defined criteria,
and observations that lead to these conclusions are discussed.
Objectives
• Differentiate between chemical and physical changes.
• Describe features that identify changes as chemical or physical.
• List examples of physical and chemical changes, then classify
why these are chemical or physical changes.
Time Requirements
Preparation …………………………………………………………….. 5 minutes
Activities ………………………………………………………. 15 minutes each
Additional time will be needed for cleanup.
The lab may be stopped after any activity and resumed at a later
time. If stopping the lab before it is complete, ensure that all
containers of liquids are sealed to prevent evaporation.
Key
Personal protective
equipment
(PPE)
goggles gloves apron
follow
link to
video
photograph stopwatch
results and
required
submit
warning corrosion flammable toxic environment health hazard
Made ADA compliant by
NetCentric Technologies using
the CommonLook® software
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Background
Some changes are so much a part of daily life
that they are hardly noticed. Paints are mixed;
ingredients become meals; tools rust; fuels are
consumed; and rain and snow form, fall, and
then seem to disappear. Some of these changes
are physical, and some are chemical.
A physical change may be associated with a
change in the appearance, but not in the chemical composition, of a substance. In other words,
the original reactant molecules have not been
changed into different molecules in the product.
For example, a change in state is a physical
change. Solid ice and liquid water have the
same chemical composition (H2O), but the state
(solid vs. liquid) of the H2O is physically different.
Chemical changes result from the formation,
breakage, or rearrangement of chemical bonds.
Atoms of compounds are rearranged to form
product substances that differ from the original
reactant substances. A chemical change can be
depicted by an equation showing the rearrangement of atoms. Even when the identities of the
substances are unknown, some conspicuous
indicators tend to suggest a chemical change:
• Production of a gas
• Production of a precipitate, an insoluble solid
• Production of light
• Production/absorption of heat
• A color change that cannot be explained by
simple combination of colors (e.g., two colorless chemicals that form a yellow compound
when mixed)
These indicators simply suggest the likelihood that a change is chemical; physical
changes sometimes produce these effects
as well.
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EXPLORING CHEMICAL AND PHYSICAL CHANGES
Materials
Needed from the equipment kit:
Included in the materials kit:
Sodium
Aluminum
Sodium
carbonate polyacrylate, (Al) weigh
2g
dish
solution
(Na2CO3),
1 M, 15 mL
Iron
(Fe)
nail
Needed, but not supplied:
• Room-temperature water
(bottled or purified), 1 L
• Sugar, 1 g
• Table salt (sodium chloride, NaCl), 2 g
• Ice cube (small)
• Matches
• Sandpaper or emery board
Reorder Information: A replacement
kit for Exploring Chemical and Physical
Changes, item number 580302, can be
ordered from Carolina Biological Supply
Company.
Call 800-334-5551 to order.
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Polystyrene
test tubes
Test tube rack
Graduated
cylinder, 10 mL
Thermometer
Tea candle
Forceps
2 Plastic
cups
2 Medicine
cups
Electronic
balance
Ruler
Beaker, 250 mL 5 Weigh
boats
Safety
Needed from chemical kit 1:
Yellow #5
food coloring
Safety goggles, a lab
apron, and gloves are
required at all times while conducting this
investigation.
Follow the instructions closely, and observe
established laboratory safety practices, including
use of appropriate personal protective equipment described in the Safety and Activity
sections.
Blue #1 food
coloring
Needed from the chemical kit 2:
Keep all chemicals tightly sealed and away from
children and pets. Wash hands after handling
any chemicals.
Magnesium and phenolphthalein are
flammable. Keep chemicals away from
any heat or flame sources.
Hydrochloric
acid solution
(HCl), 1 M
Sodium
Copper(II)
sulfate solution hydroxide
(CuSO4), 0.5 M solution (NaOH),
1M
Sodium carbonate and sodium polycarylate cause serious eye irritation.
Sodium polyacrylate is harmful if swallowed. Copper sulfate causes skin
irritation.
Sodium hydroxide and hydrochloric
acid cause severe skin burns and eye
damage.
Copper sulfate is toxic to aquatic life.
Magnesium (Mg) ribbon
Phenolphthalein
solution*, 1%
*Bottled or purified water should be used to
remove most of the solids that are found in
tap water. Filtered water from a home water
purifier (e.g., Brita® or PUR®) works well.
If ingested, phenolphthalein is a
suspected carcinogen, mutagen, and is
suspected of causing genetic defects.
Hydrochloric acid may be toxic if
inhaled.
continued on next page
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EXPLORING CHEMICAL AND PHYSICAL CHANGES
Safety continued
Do not eat, drink, or chew gum while performing
this activity. Wash hands with soap and water
before and after performing the activity. Clean
the work area with soap and water after
completing the investigation. Keep laboratory
materials and equipment out of the reach of children and pets.
Preparation
1. Read through the procedure.
2. Obtain all materials.
3. Clean and sanitize work area.
4. Prepare two solutions of colored water
(yellow and blue). Use the graduated cylinder
to measure 10 mL of water, and add 10 mL
water to each of two small cups. Add 1 drop
of yellow #5 food coloring to one cup and 1
drop of blue #1 food coloring to the second
cup.
5. Pour water into a large cup and (if it is not
already at room temperature) allow it to come
to room temperature, the exact temperature
does not matter at this time. Use 25 mL of
the water for the activities; the remainder will
be used to rinse equipment. Use only room
temperature bottled or purified water in all
activities.
6. To prevent the thermometer from rolling off
the counter and breaking, wrap a rubber band
securely around it, avoiding the bulb. The
rubber band can be moved up or down as
needed to read temperature values.
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Weighing Chemical Reagents
When weighing chemical reagents, place a
weigh boat on the balance and tare (zero) the
balance. Add the chemical to the weigh boat
until the desired weight is reached. Remove
the weigh boat and pour the chemical into the
reaction container (e.g., test tube).
Measuring Liquids
Use the graduated cylinder to measure liquids.
Pour the liquid into the cylinder until the bottom
of the meniscus (the curved upper surface of the
liquid) is level with the desired volume indicator.
Avoiding Contamination
Rinse all equipment with water and dry after
each use, including multiple uses of the same
item within one activity. Use a new weigh boat to
measure each chemical.
Set up a wash station at the lab bench. Use
the 250-mL beaker as a waste container for
solutions and rinse water, and use one cup for
disposal of solids. Fill a second cup with water
for rinsing (as well as for use in experiments).
After using the thermometer, fill a pipet with
water and, holding the thermometer over the
waste beaker, rinse the thermometer with water.
After using a test tube or graduated cylinder, fill
a pipet with water and use it to rinse the inside
of the tube or cylinder. Rinse the pipets by
flushing them with clean water. Pour the rinse
water into the waste beaker. Repeat all rinses
twice or until item is clean. Dry all equipment.
ACTIVITY
ACTIVITY 1
ACTIVITY 2
1. Place two test tubes in test tube rack.
1. Place two test tubes in test tube rack.
2. Using a 10-mL graduated cylinder, add
2 mL of 1 M hydrochloric acid (HCl) to one
of the tubes.
2. Add 10 mL of water to one test tube with a
graduated cylinder.
3. Rinse the graduated cylinder 3 times with
your bottled water.
4. With the graduated cylinder, add 2 mL of
1 M sodium carbonate solution (Na2CO3) to
the second test tube.
5. Record the color of the contents of each test
tube in the Data Table.
6. Use the thermometer to measure the
temperature of the hydrochloric acid. Record
temperature in the Data Table. Rinse and dry
thermometer as described above.
7. Repeat step 6 with sodium carbonate
solution.
8. Combine the HCl of test tube 1 with Na2CO3
in test tube. Gently swirl to mix, and insert the
thermometer.
9. Measure and record the temperature of the
product (final temperature) in the Data Table.
10. Observe solution for 1 minute and record the
final color and any additional observations.
11. Indicate in the Data Table whether a
chemical or physical change has occurred
and explain why.
12. Pour all solutions into the 250-mL beaker.
Rinse the test tubes, thermometer, and
graduated cylinder with water and dry.
3. Add 0.3 g of preweighed sodium polyacrylate
to the second test tube.
4. Record the color of the contents of each test
tube.
5. Measure the temperature of the water and
record it in the Data Table.
6. Add the water to the test tube containing
sodium polyacrylate. Gently swirl to mix, and
insert the thermometer.
7. Measure and record the temperature of the
product.
8. Observe for 1 minute and record the final
color of the product and any additional
observations.
9. Indicate on the Data Table whether a chemical
or physical change has occurred and explain
why.
10. Dispose of the product in the trash; it may
be necessary to throw away the test tube
with the product still in it. Rinse the test
tubes, thermometer, and graduated cylinder
with water and dry.
ACTIVITY 3
1. Place two test tubes in test tube rack.
2. Add 2 mL of 0.5 M copper(II) sulfate solution
(CuSO4) to a test tube.
3. Add 2 mL of 1 M sodium carbonate solution
(Na2CO3) to a second test tube.
4. Record the color of the contents of each test
tube.
continued on next page
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ACTIVITY
ACTIVITY 3 continued
5. Use the thermometer to measure the
temperature of the CuSO4. Record
temperature in the Data Table. Rinse and dry
thermometer as described above.
6. Repeat step 5 with Na2CO3 solution.
7. Combine the contents of the two test tubes
in one. Gently swirl to mix, and insert the
thermometer.
8. Measure and record the temperature of the
product (final temperature) in the Data Table.
9. Observe for 1 minute and record the final
color and any additional observations.
10. Indicate in the Data Table whether a
chemical or physical change has occurred
and explain why.
11. Pour all solutions into the 250-mL beaker.
Rinse the test tubes, thermometer, and
graduated cylinder with water and dry.
ACTIVITY 4
A
1. Place the tea candle on a flat surface away
from any flammable materials. Record the
color of the tea candle.
2. Light the tea candle using a match.
3. Observe the tea candle for 1 minute and
record the final color and any additional
observations.
4. Based only on your observations of the tea
candle, indicate in the Data Table whether a
chemical or physical change has occurred
and explain why.
B
1. Place one small ice cube in the aluminum (Al)
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weigh dish. Record the color of the ice.
2. Hold the aluminum dish over the flame of the
candle using forceps.
3. Observe for 1 minute and record the final
color and any additional observations of the
ice cube. Place hot aluminum dish on a plate
or heat-safe surface.
4. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
5. Extinguish the candle.
6. Save the aluminum dish for Activity 11.
ACTIVITY 5
1. Place two test tubes in test tube rack. Add
5 mL of water to one test tube.
2. Add 1 g of sugar to second test tube.
3. Record the color of the contents of each test
tube.
4. Measure the temperature of the water and
record it in the Data Table.
5. Add the water to the test tube containing
the sugar. Gently swirl to mix, and insert the
thermometer.
6. Measure and record the temperature of the
product.
7. Observe for 1 minute and record the final
color and any additional observations. Record
any temperature change that may have
occurred.
8. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Pour all solutions into the 250-mL beaker.
Rinse the test tubes, thermometer, and
graduated cylinder with water and dry.
ACTIVITY 6
A
1. Place one test tube in test tube rack. Add
2 mL of 1 M sodium hydroxide solution
(NaOH) to test tube.
2. Record the color of the solution.
3. Observe the solution of 1% phenolphthalein
solution and record the color.
4. Measure the temperature of the NaOH and
record it on the Data Table.
5. Using a pipet, add 1 drop of phenolphthalein
to the NaOH solution. Gently swirl to mix, and
insert the thermometer.
6. Measure and record the temperature of the
product.
7. Observe for 1 minute and record the final
color and any additional observations.
8. Indicate on the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Save the NaOH/phenolphthalein solution
for use in Part B.
B
1. Place one test tube in test tube rack. Add
2 mL of 1 M hydrochloric acid solution (HCl)
to test tube.
2. Record the color of the HCl.
3. Measure the temperature of the HCl and
record it in the Data Table.
4. Add the HCl to the NaOH/phenolphthalein
solution prepared in Part A. Gently swirl to
mix, and insert the thermometer.
5. Measure and record the temperature of the
product.
6. Observe for 1 minute and record the final
color and any additional observations.
7. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
8. Pour all solutions into the 250-mL
beaker. Discard pipet used to dispense
phenolphthalein solution in trash. Rinse the
test tubes, thermometer, and graduated
cylinder with water and dry.
ACTIVITY 7
1. Place two test tubes in test tube rack. Add
2 mL of copper(II) sulfate solution (CuSO4) to
one test tube.
2. Add 2 mL of sodium hydroxide solution
(NaOH) to the second test tube.
3. Record the color of the contents of each test
tube.
4. Measure the temperature of the CuSO4 and
NaOH solutions and record them in the Data
Table.
5. Add the contents of one test tube to the other
test tube. Gently swirl to mix, and insert the
thermometer.
6. Measure and record the temperature of the
product.
7. Observe for 1 minute and record the final
color and any additional observations.
8. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Pour all solutions into the 250-mL beaker.
Rinse the test tubes, thermometer, and
graduated cylinder with water and dry.
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ACTIVITY
ACTIVITY 8
1. Place two test tubes in test tube rack. Add
5 mL of blue or yellow water, prepared in
Preparation section above, to test tubes.
2. Record the color of the contents of each tube.
3. Use the thermometer to measure the
temperature of the blue water. Record
temperature in the Data Table. Rinse and dry
thermometer.
4. Repeat step 3 with yellow water.
5. Add the contents of one test tube to the other
test tube. Gently swirl to mix, and insert the
thermometer.
6. Measure and record the temperature of the
product.
7. Observe for 1 minute and record the final
color and any additional observations.
8. Indicate on the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Pour all solutions into the 250-mL beaker.
Rinse the test tubes, thermometer, and
graduated cylinder with water and dry.
ACTIVITY 9
1. Place one test tube in test tube rack. Add
5 mL of hydrochloric acid solution (HCl) to
test tube.
2. Measure the temperature of the HCl and
record it on the Data Table.
3. Record the color of the HCl.
4. Record the color of the magnesium ribbon.
5. Cut a 0.5-cm length of magnesium ribbon
and add it to the HCl. Gently swirl to mix, and
insert the thermometer.
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6. Measure and record the temperature of the
product.
7. Observe for 1 minute and record the final
color and any additional observations.
8. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Pour all solutions into the 250-mL beaker.
Discard any solids in the trash. Rinse the test
tubes, thermometer, and graduated cylinder
with water and dry.
ACTIVITY 10
1. Place two test tubes in test tube rack. Add
5 mL of copper(II) sulfate (CuSO4) to one test
tube.
2. Add 2 g of table salt (sodium chloride, NaCl)
to the second test tube.
3. Record the color of the contents of each test
tube.
4. Measure the temperature of the CuSO4
solution and record it in the Data Table.
5. Add the CuSO4 solution to the test tube
containing the salt. Gently swirl to mix, and
insert the thermometer.
6. Measure and record the temperature of the
product.
7. Observe for 1 minute and record the final
color and any additional observations.
8. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Save the CuSO4/salt solution for use in
Activity 11.
ACTIVITY 11
1. Cut several pieces of aluminum
(approximately 1 cm × ½ cm each) from the
aluminum dish used in Activity 4.
2. Record the color of the aluminum pieces in
the Data Table.
3. Measure the temperature of the CuSO4/salt
solution prepared in Activity 10 and record
it in the Data Table. Rinse thermometer as
described above.
4. Record the initial color of the CuSO4/salt
solution in the Data Table.
5. Place the nail in the CuSO4. Allow it to remain
there for 1 minute.
6. Using forceps, remove the nail from the
solution.
7. Measure and record the temperature of the
solution.
8. Examine the nail and the solution. Record the
final color of the CuSO4 solution and the nail,
and any additional observations.
9. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
5. Place the aluminum metal pieces in the
CuSO4/salt solution.
10. Pour all solutions into the 250-mL beaker.
Discard any solids in the trash. Rinse the
test tubes, thermometer, and graduated
cylinder with water and dry.
7. Record any observations.
Disposal and Cleanup
6. Measure and record the temperature of the
product.
8. Indicate in the Data Table whether a chemical
or physical change has occurred and explain
why.
9. Pour all solutions into the 250-mL beaker.
Discard any solids in the trash. Rinse the test
tubes and thermometer with water and dry.
1. Dispose of all liquid waste in sink, flushing
with copious amounts of tap water. Return all
unused chemicals to the chemical supply kit.
2. Clean and dry all equipment and return to the
equipment kit.
3. Clean and sanitize work space.
ACTIVITY 12
1. Place one test tube in test tube rack. Add
5 mL of copper(II) sulfate solution (CuSO4) to
test tube.
2. Measure the temperature of the CuSO4 and
record it on the Data Table.
3. Using a small piece of sandpaper or emery
board, lightly sand the exterior of the iron (Fe)
nail.
4. Record the color of the CuSO4 solution and
the nail.
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ACTIVITY
Data Table.
Color
of
Initial
Activity
Items
Color
of Final
Items
1
2
3
4A
4B
5
6A
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Initial
Temp.
(°C)
Final
Temp.
(°C)
Observations
Type of
Change
Explanation
Color
of
Initial
Activity
Items
Color
of Final
Items
Initial
Temp.
(°C)
Final
Temp.
(°C)
Observations
Type of
Change
Explanation
6B
7
8
9
10
11
12
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NOTES
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CHEMISTRY
Exploring Chemical and Physical Changes
Investigation Manual
www.carolina.com/distancelearning
866.332.4478
Carolina Biological Supply Company
www.carolina.com • 800.334.5551
©2016 Carolina Biological Supply Company
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