Fire!
Chem Catalyst
Fired Up
Today you will be observing several
different combustion reactions.
1.) What do you think a combustion
reaction is?
2.) There are 3 general things needed for
a combustion reaction to occur – what
are they?
Fire Safety
• Tie back long hair, which is especially
flammable when mixed with hair spray.
Avoid loose clothing.
• Small fires may be extinguished by
smothering flames with water, sand, or
a fire blanket. A carbon dioxide fire
extinguisher can be used to combat
most fires, except fires caused by
metals.
The Big Question
• What are the characteristics of fire?
Making Sense
• Changes in matter involve changes in
energy.
• Exothermic process: A process that
releases energy in the form of heat.
• Reactions of elements and compounds
with oxygen typically are exothermic.
• Combustion requires oxygen.
Predict-Explain-ObserveExplain
• A strip of paper is dipped into a mixture
of isopropyl alcohol (C3H8O) and water.
• Predict what will happen to the paper
when it is lit on fire. Explain why you
said what you said.
• Observe the demonstration.
• Explain what happened.
Chem Catalyst
Not So Hot
1. How do you think hand warmers
work? Where does the heat come
from?
Lab introduction
• You will be observing three chemical
processes today. Focus on the heat
transfer in each one.
• Work in groups of four.
• Follow directions at the three stations.
Preliminary Definition of Energy
• Energy: A measure of the work involved in
moving or changing something.
Ex: changes in temperature
• Energy is not a substance (i.e. energy is
NOT matter)
Definition of Heat
• Heat: A transfer of energy between two
substances due to temperature
differences.
• To look at heat, we have to define the
system and surroundings.
System and Surroundings
• System: The process you are focusing
on. In this case, a chemical reaction.
• Surroundings: Everything outside the
system (thermometer, beaker, your
body)
Definitions
•
-
Exothermic:
Feels warm
Gives off heat
Heat transfers from the reaction  your hand
•
-
Endothermic Reaction:
Feels cold
Absorbs heat
Heat transfers from your hand  the reaction
Computer Simulation
• Molecular workbench: search
“exothermic”, explosion.
• What is happening during an explosion?
How is energy transferred?
Chem Catalyst
• Imagine you are sitting near a campfire.
You feel warm.
– Explain how you think burning wood
transfers heat to your body.
– The next morning you find ashes that are
the same temperature as the air. Explain
why the ashes are no longer hot.
ChemCatalyst
• You have water at 25ºC. You dissolve
ammonium acetate, NH4C2H3O2, in the
water and find that the temperature
decreases to 17ºC.
1.) Is the process exothermic or endothermic?
2.) How will it feel if you put your hand on it?
3.) In which direction is the heat transferring?
Purpose
• Today’s question: How do we consider
energy transfer from different points of
view?
Making Sense
Instructions for the water
stations
Making Sense
• Was the lukewarm water at the water
station hot or cold?
• Why did the lukewarm water feel hot to
one hand and cold to the other?
• If you say something is “hot,
what do you mean?
• If you say something is “cold,” what do
you mean?
“Hot” and “Cold”
• For the rest of the Fire unit, we won’t
say anything is “hot” or “cold.”
• Instead, we can say…
Definitions
• Heat (thermal energy) always transfers
from the warmer object to the colder
object.
• Thermal equilibrium: when two objects
in contact with each other reach the
same temperature.
Laws of Thermo
• First Law of Thermodynamics: Energy is
conserved. (we can transfer energy,
but you can’t create or destroy it)
• Second Law of Thermo: Energy tends
to disperse - energy flows from objects
of high temperatures to low temps.
Check-In
• Imagine that a thermometer is placed in
a beaker of water and the temperature
is noted. An ice cube is dropped into
the water, and after ten minutes the
temperature is noted again.
– What will you observe?
– What is the direction of energy transfer?
Chem Catalyst
• You are standing outside freezing with
no gloves on for several minutes. You
sneeze and get stuff all over your
hands. When you come into the house,
you turn on the cold faucet and start
washing your hands. Why do your
hands feel so hot under the water?
Draw a picture of the direction of heat
transfer.
Exercise
• Write two sentences, using proper
English, that use the word “heat”.
• After you are done, identify the part of
speech that you use “heat” as for both
of your sentences.
ChemCatalyst
• A thermometer is placed in a beaker of water
and the temperature is 21ºC. An ice cube is
dropped into the water and after 10 minutes
the temperature is 14ºC.
– Is this an endo or exothermic process?
– What is the change in temperature?
– Draw a picture showing the direction of heat
transfer.
Chem Catalyst
Heat versus Temperature
• Chemists talk about the “average kinetic
energy” of molecules very often. What
do you think this means?
• What chemistry tool could you use to
measure the “average kinetic energy” of
molecules?
Chem Catalyst
Heat versus Temperature
• A lead atom is moving at 40 mph. A
hydrogen atom is also moving at 40 mph.
Will they have the same temperature or
different? Why?
Go to computer lab for Heat
vs. Temp simulation
• Priority #1 =
Finishing this assignment
• When you are finished, you can work on
anything else that is appropriate.
Chem Catalyst
Heat versus Temperature
• Write “1/2 day open note quiz” for your
chem catalyst
• Take out any papers you want to use for
the optional NeilMed quiz
• I will take whichever grade is higher –
either your NeilMed project or the quiz
Recall:
• Thermal equilibrium is reached when
two objects in contact with one another
reach the same temperature.
Online Simulation
• http://jersey.uoregon.edu/vlab/Thermod
ynamics/index.html
• Experiments #1 and #5
Questions about the simulation
• What happens when you heat the gas
atoms in the simulation?
• Are all the atoms moving at the same
speed?
• What happens to the sample when you
add atoms?
• How can you make the heat energy of
the sample increase without increasing
the temperature of the sample?
Heat vs. Temperature Lab
Making Sense
Key Points
• The final temperature of a mixture
depends on mass and temperature of
the samples.
• Are heat and temperature the same?
Definition
• Thermal Energy - The total kinetic
energy associated with the mass and
motions of the particles in a sample of
matter.
Definition
• Calorie: The amount of energy it takes
to raise the temperature of one gram of
water by one degree Celsius.
• The equation for heat transfer in water
is:
Sample problem
• How much heat transfer is required to
raise the temperature of 5.0 g of water
from 25ºC to 75ºC?
ChemCatalyst
• GET A CALCULATOR PLEASE
• You have one beaker containing 500 g of
water at 75ºC. You also have a beaker with
2000 g of water at the same temperature.
1.) Which will melt more ice? Explain your
answer in terms of thermal energy, heat
transfer, and temperature.
Discussion
• Does total energy depend on the
amount of a substance?
• Does the temperature depend on the
amount of a substance?
• What factors determine how much
energy can be transferred from one
object to another?
ChemCatalyst
1.) Come up to the front of the room and
record the temp of both black objects.
2.) Touch both objects. Which do you
think will melt an ice cube faster? Why?
3.) Observe what happens when an ice
cube is placed on each.
Chem Catalyst
• Imagine you are at the beach. The sun has
been shining all day long, and you want to
go for a swim.
– How does the sand feel on your feet? How will
the water feel?
– You go back out to the beach at night for a
swim. How does the sand feel now? What
about the water?
Chem Catalyst
• Rank the following substances from coldest
to warmest in terms of how they will feel
when you touch them.
Wood
Metal
Rubber Stopper
Candle
Rock
Plastic pipe
Explain your predictions, please. 
Items from Lab
Which substances felt coldest?
Wood
Metal
Rubber Stopper
Candle
PVC
Rock
= 0.6 cal/g*ºC
= 0.092 cal/g*ºC
= 0.48 cal/g*ºC
= 0.7 cal/g*ºC
= 0.215 cal/g*ºC
= 0.19 cal/g*ºC
Notes
Specific Heat Capacity (C):
The amount of energy (in calories) needed to
raise the temperature of 1 gram of a substance
by 1 degree Celsius
Different materials have different heat capacities
Specific heat capacity for water:
1.00 cal
g * ºC
In other words, it takes ____ calories to raise
___ grams of water by ____ degrees Celsius
Notes
Substances with Low Heat Capacity
- Transfer heat energy easily (good heat
conductor)
- Heat up quickly
- Cool down quickly
Ex: Metals, rocks
Substances with High Heat Capacity
- DO NOT transfer heat easily
- Heat up slowly
- Cool down slowly
Ex: Wood, Water
Class Demonstration
How can you explain why the ice cube melted
faster on the black metal square? Use what
you know about energy transfer and heat
capacity.
Class Demonstration
Feel both black substances.
If an ice cube is placed on each substance,
which will make it melt faster?
ChemCatalyst
You have two unknown substances. They
each have a temperature of 65 degrees F.
The first substances has a heat capacity of
0.12 cal/g*C. The second substance has a
heat capacity of 0.63 cal/g*C.
Which substance will melt ice faster and WHY?
Calculating the amount of
heat transferred
Heat = mass x specific heat capacity x temperature change
Heat = m•C •(Tfinal - Tinitial)
Notes
• Since water requires more energy to raise its
temperature, we say that water has a higher
heat capacity than ethanol.
Cwater
cal
1
ggC
Cethanol
cal
 0.58
ggC
• Let’s translate this to “regular English”
Notes
Cwater
cal
1
ggC
Cethanol
cal
 0.58
ggC
• How many calories does it take to raise the temp of
50 g of ethanol by 1ºC?
• How many calories does it take to raise the temp of
50 g of ethanol by 25ºC?
Practice Problems
• How many calories does it take to raise
the temperature of 22 g of brass from
18.0 ºC to 25 ºC? The specific heat
capacity of brass is 0.09 cal/g•ºC.
• How much does the temperature increase
if you have a 6 g sample of brass and you
add 690 calories of heat energy to it?
Notes
• Do you think metals have a higher or
lower heat capacity than water?
Explain. (Think about heating a pot of
water on the stove. Which one heats up
more quickly?)
Tomorrow’s Lab
• You will be given an unknown metal. You will
have to identify the type of metal it is by
determining it’s specific heat capacity.
• Materials:
- Styrofoam cup
- Water
- Scale (electronic balance)
- Thermometer
- Your metal at a known temperature
- Chart with specific heat capacity of metals
What do you need to know
(or measure)?
ChemCatalyst
• Two students are debating how much
water should be used in the lab today.
Fernando says that you should use as
little water as possible. Shaquanda
says that you should use as much water
as you can to fill the cup.
• Who has the better idea and why?
Check-In
• How many calories of energy are
needed to raise the temperature of 32 g
of aluminum by 23 degrees Celsius?
ChemCatalyst
• The first step of yesterday’s lab was to
calculate the calories of energy transferred
to the water.
1.) Why can we use this value when we
calculate the specific heat of the metal?
2.) Why would it improve your results to stir
the water when you drop in the metal?
Chem Catalyst
It’s a sunny day and you find a
park bench. You’re wearing
some shorts like the oldschool basketball players
used to wear and you go to sit
on the bench.
1.) Do you sit on the metal parts
or the wooden parts of the
bench? Why?
Check-in
• The specific heat capacity of aluminum
is 0.22 cal/gºC.
• Translate the specific heat capacity to
English.
• How much energy does it take to raise
10 g of aluminum by 10 degrees
Celsius? How much energy does it take
to raise 10 g of water by 10 degrees
Celsius (the specific heat capcity of
water s 1 cal/gºC)?
Chem Catalyst
GRAB A CALCULATOR
The specific heat of stainless steel is 0.12
cal/g*ºC. How many calories does it take to
raise the temperature of 2.5 g of stainless
steel from 25.0 ºC to 99.5 ºC?
Question of the day
• You have a piece of metal that is 100ºC and
place it against another piece of metal that is
25ºC.
• What happens to the two pieces of metal over
time?
• Describe how you think energy is transferred
from one object to the other in terms of how
the atoms are moving in both objects. Think
about the “heat vs. temperature” simulation
and how the fast and slow molecules
transferred energy.
Whiteboarding
• With a group of 3, whiteboard the following:
• Draw molecular pictures of two solids
separated by a space.
• The solid on the left has a higher average
kinetic energy than the solid on the right.
(what does that mean in terms of their
temperatures?)
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
Whiteboarding continued…
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
• In three separate pictures, show how the heat
is conducted (transferred) from one object to
another if the following items were placed
between the two solids: another solid, a
liquid, or a gas.
• Be able to answer the question “Which object
conducts energy better and why?”
Myers, Alexis
Kangas, Jared
Dolgos, Kelley
Randolph, Paris
Kiefer, Kelley
Thomas, Sean
Dolin, Tyler
Castle, Tim
Gardner, Jawaad
Baker, Benjamin
Galdes, Nathan
Hochstein, Molly
Bradley, Andrea
Thomas, Zane
Burdock, Jacob
Holden, Katrina
Harris, Nicolas
Pennington, Jacqueline
Flowers, Doniesha
Cane, Rachel
Taylor, Chanelle
Williams, Rhiana
Dye, Carlynn
Rooks, Jemar
Jenkins, Crystal
White, David
Killmar, Jordan E
van Well, Tyler
Sanford, Ashley
Wiley, Cody
1
1
1
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
7
7
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8
8
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10
10
Chem Catalyst
• You have a pot of ice on the stove. You
heat up the water until it is boiling.
Temp
– If you graphed the temperature of the water
over the time you are heating it, what do you
think the graph will look like?
Time
http://molo.concord.org/databa
se/activities/170.html
Chem Catalyst
When you have ice in a drink, the
temperature will remain very close to 0 ºC.
Only once all the ice has melted with the
temperature start to rise.
• Why is this true? Think about heat transfer
Heating Curve of Water
ChemCatalyst
1.) What phase or phases of matter are
present at points 1,2,3,4 & 5 on the
heating curve of water?
Online Simulation
• http://jersey.uoregon.edu/vlab/Thermod
ynamics/index.html
Definition
• Thermal equilibrium is reached when
two objects in contact with one another
reach the same temperature.
ChemCatalyst
You have two unknown substances. They
each have a temperature of 65 degrees F.
The first substances has a heat capacity of
0.12 cal/g*C. The second substance has a
heat capacity of 0.63 cal/g*C.
Which substance will melt ice faster and WHY?
Chem Catalyst
• Pretend you have a really cold drink in
your hand. Which of the following
substances would you want to wrap
around it to keep it cold, and WHY???
-Aluminum foil, wood, or styrofoam?
Justify your answer.
Specific Heat capacity of some
metals
Metal
Specific Heat
Capacity
Aluminum
0.22 cal/g*C
Lead
0.031 cal/g*C
Zinc
0.093 cal/g*C
Initial Temp.
Final Temp.
Severe second degree “burn”
from salt/ice challenge
After effects of salt/ice challenge
Do conduction online demo
• Heat and temp molecular workbench
demo – day two
Chem Catalyst
1.) Name three substances that will
combust or burn.
2.) Name three substances that do not
combust.
Demonstration
• Do metals combust? Let’s refresh our
memories with magnesium.
Types of bonding
• Covalent =
• Ionic =
• Metallic =
• Elemental nonmetal =
Demonstrations
• Let’s make predictions if the following
substances will combust:
– Lamp Oil
– Sodium chloride
– Calcium carbonate
– Iron
College Readiness Writing Prompt
In some states, legislators have debated whether
teenagers should be required to maintain a “C”
grade average in school before receiving a driver’s
license. Some people think this would be a good
policy because having passing grades shows that
students are responsible enough to be good
drivers. Other people think such a policy would not
be appropriate because they see no relationship
between grades in school and driving skills. In your
opinion, should teenagers be required to maintain
a “C” average in school before receiving a driver’s
license?
Patterns of combustion
• Things that combust:
– Most covalent molecules
– Things with lots of C and H
– Most metallic compounds
• Things that do not combust:
–
–
–
–
Ionic compounds
Water
Carbon dioxide
Oxygen gas
ChemCatalyst
• Which of the following substances are
likely to combust? What is your
reasoning?
– C5H12, pentane
– CaBr2, calcium bromide
– Na, sodium
Chem Catalyst
• Will the following substances combust or
not? Why?
-
Bromine gas, Br2
Pentane, C5H12
Carbon Monoxide gas, CO
Potassium, K
Magnesium nitrate, MgNO3
Question
• Burning wood for a campfire is a
combustion reaction. Where does the
energy come from that keeps the fire
burning?
Notes
• Bond breaking:
requires energy. It takes energy to break
the bonds that hold molecules together.
• Bond making:
releases energy. Forming new bonds to
create new products actually releases
energy.
“Make it or Break It”
Use the molecular model kits to have
students build molecules necessary for the
combustion of methane.
ChemCatalyst
It takes 860 kJ/mol of energy to break the
bonds in the reaction of hydrogen gas and
oxygen. 1050 kJ/mol of energy is released
from forming the product, water.
1.) What is the net energy exchange? (or
heat of reaction)
2.) Is this reaction endo or exothermic? How
do you know?
Making Sense
• Reactions transfer heat.
• If the thermometer measured an
increase in temperature, which direction
was heat being transferred?
Reaction
Making Sense
• If the thermometer measured a decrease in
temperature, which direction was heat
being transferred?
Reaction
Making Sense
• When heat is transferred from the
surroundings to the system (into the
reaction), the reaction is called endothermic.
Reaction
Making Sense
• When heat is transferred from the system to
the surroundings (exiting the reaction), the
reaction is called exothermic.
Reaction
Chem Catalyst
• You have water at 43ºC. You dissolve
ammonium acetate, NH4C2H4O2, in the
water and find the temperature
decreases to 24ºC.
1.) What is ∆T? Is it positive or negative?
2.) Is the process exothermic or
endothermic?
3.) Is energy transferring from the solution
to the environment or from the
environment to the solution?
Chem Catalyst
GRAB A CALCULATOR
The specific heat of stainless steel is 0.12
cal/g*ºC. If you used 900 calories to heat
2.3 g of stainless steel, how much did you
raise the temperature?
Rearranged equation:
q
∆T
m*C
Re-worked probs for Fire 1
• Point of View: Draw pictures of heat
transfer, Making sense
• Heat vs. Temp Summary: 1, 2, 3, 4, 5, 6
• The heat is on: Part 2, #2, 3, Making
Sense
• Where’s the heat: Draw a heating curve
graph, #1, #3
• You’re Fired: #1-5
• Hot and Cold: #2, #3, #7a,b,c
Chem Catalyst
• The following table shows the balanced
chemical equations for four combustion
reactions. List three patterns that you notice.
Substance
Combustion reaction
methane
CH4 + 2O2 --> CO2 + 2H2O
ethanol
C2H6O + 3O2 --> 2CO2 + 3H2O
glucose
C6H12O6 + 6O2 --> 6CO2 + 6H2O
magnesium
2Mg + O2 --> 2MgO
Making Sense
• Write the equation for the combustion of
the following substances:
Sodium, Na
Propanol, C3H8O
Check-in
• Pick a substance that combusts from
the list below and write the balanced
chemical reaction.
• K
• C2H6O
• CH4O
Chem Catalyst
• Standard automobiles use a mix of carbon-based
compounds (high in octane) as fuel. The cars that
race in the Indianapolis 500 use methanol as fuel, and
top dragsters use nitromethane as fuel.
• Balance the equations for the combustion of these
fuels.
• Why do you think they use different fuels for different
types of driving?
(octane) ___C8H18 + ___O2 --> ___CO2 + ___H2O
(methanol) ___CH4O + ___O2 --> ___CO2 + ___H2O
(nitromethane) ___CH3NO2 + ___O2 --->
___CO2 + ___H2O + ___NO2
Chem Catalyst
1.) Below is the heating curve of water. What phase (or
phases) of matter are present at points 1, 2, 3, 4, and 5?
2.) Why does the temp stay constant at stages 2 and 4?
Quick Calculation
• Octane (C8H18) generates 1300 kilocalories per mole
burned.
• How many calories are in 1 kilocalorie?
• What is the molar mass of octane?
• What’s another way of writing the molar mass?
• How many kilocalories are produced for every gram of
octane?
Making Sense
• Metric units of energy (what scientists
normally use) = Joule
• 1 calorie (cal) = 4.184 Joules (J)
• 1000 calories = 1 kcal
• 1000 J = 1 kJ
• 1 kilocalorie (kcal) = 4.184 kilojoules (kJ)
Practice Problems Use Factor Labeling
• Convert 15 calories to Joules.
• Convert 2500 calories to kilojoules.
Chem Catalyst
• Previously, we learned that endothermic
reactions absorb heat energy. These
reactions feel colder as the reaction
proceeds.
1.) If energy is absorbed by the reaction,
why does it feel colder? Where does the
energy go?
Chem Catalyst
• Humans generate energy from burning
fuels, such as coal, oil, natural gas, and
hydrogen. For example, the
combustion of coal can be written as
C (s) + O2 (g) --> CO2 (g)
• Do you think you can reverse the
reaction to form coal, C(s), and oxygen,
O2, from CO2? Explain your thinking.
Honors Chem:
The rest of the year…
•
•
•
•
Tuesday: Make sparklers
Wednesday: Fire Starter
Thursday: Study day for finals
Friday: Optional 20 question MC quiz
for Fire Investigation 2 (All-a-glow,
Fuelish choices, No going back, Fire
Starter)
• Monday: Study day, light sparklers
• Tuesday: Final Exam, 80 questions MC
Demos
• Demo 1 - Combustion of hydrogen
• Demo 2 - Decomposition of water
Energy Diagrams
2 H2 + O2
2 H2 + O2
-286 kJ/mol H2
+286 kJ/mol H2
2 H2O
2 H2O
Reaction 1: Combustion of hydrogen
Reaction 2: Decomposition of water
2H2 + O2 --> 2H2O
2H2O --> 2H2 + O2
Energy Diagrams
• Heat of reaction (rxn): The amount of
energy gained or lost in a rxn. If the
heat of rxn is negative, the rxn is
exothermic. If the heat of rxn is
positive, the rxn is endothermic.
Notes
• Law of conservation of energy: Energy
is neither created nor destroyed.
Chem Catalyst
• Sketch an energy diagram for the
combustion of carbon (coal) to form
carbon dioxide. The heat of reaction is 394 kJ/mol.
• What energy is required to form coal
from carbon dioxide?
Chem Catalyst
In the previous lesson we showed you an empty energy
diagram for the combustion of hydrogen. This new
energy diagram is more accurate.
1.) What is different about this diagram?
2.) Does more energy go into breaking the bonds, or is
there more energy released from making bonds?
3.) Does this represent an endo or exothermic rxn?
2H2 + O2
-286 kJ/mol H2
2H2O
Energy Diagrams
Reactants
Ea
Products
Energy of Activation: The energy that is required to get a
reaction started.
Making Sense
Reactants
Ea
Products
Bond energy: The energy required to break a bond. Bond
breaking is endothermic (it takes energy to break a bond).
Bond making is exothermic.
Check-in
Reactants
a.
Products
b.
c.
-Which arrow represents the activation energy - heat going
into the system?
-Which arrow represents the heat of reaction - net energy
released by the reaction?
-For the reaction described by the energy diagram, is the
energy required to break bonds greater than the energy
released upon forming bonds?
-Is the reaction endothermic or exothermic?
Chem Catalyst - Review
• Propane (C3H8) burns in air to produce
water and carbon dioxide. If 25.0 g of
propane were burned, how many grams
of water were produced?
• Write a balanced equation and set up a
BCA table. This involves several steps,
so make sure you don’t skip any.
Gas Law Problems
• A gas in a closed, rigid container has a pressure of
1.5 atm at a temperature of 30ºC. If the
temperature of the gas is raised to 250ºC, what is
the new pressure?
• A gas in a syringe has a pressure of 700 mmHg
and a volume of 45 mL. If the volume is
decreased to 32 mL, what is the new pressure?
• A gas in a closed container has a pressure of 14
psi and has 3.5 moles of gas. If the amount of gas
is increased to 4.6 moles, what will the new
pressure be?
Heat Transfer Problem
• Which of the following takes more energy to
do? Justify your answer with a calculation.
• Heating a 5.0 g piece of aluminum from 10ºC
to 25ºC. The specific heat capacity for
aluminum, CAl = 0.22 cal/gºC.
• Heating 5.0 g of water from 10ºC to 13ºC.
The specific heat capacity for water, Cwater =
1.0 cal/gºC.
Video Demonstration
• http://www.youtube.com/watch?v=yTzcoyzPQ
E0
• Reaction between barium hydroxide and
ammonium thiocyanate (basically the same
reaction as what’s on your worksheet)
• Beginning Temp:
• Ending Temp:
• Temp Difference = Tfinal - Tinitial =
Reaction of copper sulfate in
water - demonstration
• Beginning Temp =
• Final Temp =
• Temp Difference =
Tfinal - Tinitial =
Lab demonstration for today
Making Sense - Temp differences
Team Demo
1
2
3
4
5
6
7
8
S1
S2
S3
S4
S5
Classify the reactions as
endothermic or exothermic
•
•
•
•
•
•
Combustion:
Ba(OH)2*8H2O + 2NH4NO3:
Dissolving CaCl2:
Dissolving of NH4Cl:
Dissolving of CuSO4:
NaOH + HCl:
Check-in
• You have water at 25ºC. You dissolve
ammonium acetate, NH4C2H4O2, in the
water and find the temperature
decreases to 15ºC.
– Is heat being transferred from the solution
to the environment or from he environment
to the solution?
– Is the process exothermic or endothermic?
Test on Fire Inv. 1
Investigation 2
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All a Glow
Fuelish Choices
No going back
Fire Starter
Sparklers