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Energy
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There are things that ________________________have mass and volume.
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These things fall into a category we call __________________________.
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Energy is anything that has the capacity to do_______________________________.
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Although chemistry is the study of matter, matter is _________________________by energy.
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It can cause physical and/or chemical changes in matter.
Law of Conservation of Energy
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“Energy can neither be ________________nor______________________.”
The ___________________amount of energy in the universe is constant. There is no process that can
increase or decrease that amount.
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However, we can _____________________energy from one place in the universe to another,
and we can ________________________its form.
Matter Possesses Energy
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When a piece of matter possesses energy, it can give _______________of it to another object.
 It can do ___________________on the other object.
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All chemical and physical changes result in the matter changing_______________________.
Kinds of Energy--Kinetic and Potential
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Potential energy is energy that is_____________________________.
 Water flows because gravity pulls it downstream.
 However, the dam won’t allow it to move, so it has to store that energy.
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Kinetic energy is energy of ________________, or energy that is being
_________________________________from one object to another.
 When the water flows over the dam, some of its potential energy is
________________________________to kinetic energy of motion.
Some Forms of Energy
•
•
Electrical Kinetic energy associated with the ____________________________________.
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Heat or Thermal Energy Kinetic energy associated with ____________________________.
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Light or Radiant Energy Kinetic energy associated with _____________________in an atom.
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Nuclear Potential energy in the________________________________ of atoms.
Chemical Potential energy in the ______________of atoms or because of their____________.
Converting Forms of Energy
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When water flows over the dam, some of its potential energy is __________________to kinetic
energy.
 Some of the energy is stored in the water because it is at a higher elevation than the
surroundings.
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The __________________________________of the water is kinetic energy.
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Along the way, some of that energy can be used to push a turbine to generate______________.
 Electricity is one form of_____________________________________.
 The electricity can then be used in your home. For example, you can use it to heat cake
batter you mixed, causing it to change chemically and _____________________some of
the energy in the new ____________________________that are made.
Using Energy
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We use energy to accomplish all kinds of processes, but according to the
______________________________we don’t really use it up!
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When we use energy we are __________________it from one ________________to another.
 For example, converting the ________________________energy in gasoline into
________________________energy to make your car move.
Total______________
Total________________
“Losing” Energy
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If a process was_____________________, we could theoretically get all the energy
transformed into a_____________________________.
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Unfortunately we cannot get a 100% efficient process.
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The energy ________________in the process is energy transformed into a form
we__________________________________.
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Only about _____________of the energy from the fuel you put in your tank gets used to move
your car down the road or run useful accessories, such as air conditioning. The rest of the energy
is ________to engine and driveline inefficiencies and idling. Therefore, the potential to improve
fuel efficiency with advanced technologies is enormous.
There’s No Such Thing as a Free Ride
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When you drive your car, some of the ________________________energy stored in the
gasoline is released.
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Most of the energy released in the combustion of gasoline is transformed into sound or heat
energy that adds energy to the_________________ rather than move your car down the road.
Units of Energy
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Calorie (cal) is the amount of energy needed to raise _________ gram of water by ________°C.
 kcal = energy needed to raise 1000 g of water 1 °C.
 food calories = kcals.
Units of Energy
Energy Conversion Factors:
1 calorie (cal) = ______________joules (J)
1 Calorie (C) = _______________ calorie (cal)
1 kilowatt-hour (kWh) = ______________ joules (J)
Energy Use
Unit
Energy
Energy Required
Required to
to Raise
Light 100-W
Temperature of 1 g Bulb for 1
of Water by 1°C
Hour
5
joule (J)
4.18
3.6 x 10
calorie (cal)
1.00
8.60 x 10
Calorie (Cal)
1.00 x 10
kWh
1.1 x 10
-3
-6
4
Energy
Used by
Average
U.S. Citizen
in 1 Day
9.0 x 10
2.2 x 10
8
8
5
86.0
2.2 x 10
0.100
2.50 x 10
2
Solve: 2567 cal were used to heat a container of water how many Joules is this?
Given:
Find:
Conversions Factors:
Solve & Check:
Solve: 569.0 J of energy were added to a piece of iron when it was heated in a fire how many
calories is this?
Given:
Find:
Conversions Factors:
Solve & Check:
Solve: 250.0 kWh were used in a light bulb, how many joules is this?
Given:
Conversions Factors:
Solve & Check:
Find:
Solve: A light stick uses 55500 cal of energy how many kcal is this?
Given:
Find:
Conversions Factors:
Solve & Check:
Solve: 25.0 kJ of heat were added to a piece of gold how many joules is this?
Given:
Find:
Conversions Factors:
Solve & Check:
Solve: A candy bar contains 225 Cal of nutritional energy. How many joules does it contain?
Given:
Find:
Conversions Factors:
Solve & Check:
Solve: Convert 589 Cal to Joules
Given:
Find:
Conversions Factors:
Solve & Check:
Chemical Potential Energy
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The amount of energy _____________________in a material is its chemical potential energy.
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The stored energy arises mainly from the attachments ________________________in the
molecules and the attractive forces_____________________________.
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The stored energy arises from the attractive forces between molecules.
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When materials undergo a physical change, the attractions ______________ molecules change
as their____________ changes, resulting in a change in the amount of chemical potential energy.
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When materials undergo a physical change, the attractions between molecules change as their
position changes, resulting in a change in the amount of
__________________________energy.
Chemical Potential Energy continued
The stored energy also arises from the attachments
between __________________ in the molecules
When materials undergo a chemical change, the
_____________________of the molecules change, resulting
in a change in the amount of chemical potential energy
Converting Forms of Energy
Chemical energy is stored in fuels like methane (natural gas) and gasoline. Let's see how methane
combining with oxygen (combustion) gives up this type of potential energy.
__________________collides with ___________________at high speeds (caused by flame or spark),
there's a rearrangement of the atoms. Two oxygen atoms will combine with four hydrogen (H) atoms to
form _______________________ (H2O). The other two oxygen atoms will combine with methane's
carbon atom to form carbon dioxide. Why does this give off energy?
Below is the same diagram as above, except all of the
protons and electrons that hydrogen, carbon, and
oxygen have are shown. Hydrogen has _______proton
and ________electron. Carbon has ________ protons
and ________ electrons. Oxygen has _______protons
and ________ electrons. Remember the electrons are
all being pulled on by the protons (kind of like Earth
pulling on objects on the Earth).
The reason energy is released during
rearrangement is that the electrons are
____________________to the protons than
they were originally.
When the electron on the hydrogen atom goes
from farther away to closer, energy is
_________________. Same thing is
happening here except several electrons are
involved.
This "moving" closer to the nucleus means that some of the potential energy gets
________________________ to light.
The light is the visible light you see in the picture plus a great deal of infrared light, which is the
_____________________________you feel radiating from the flame
Energy Changes & Chemical Reactions
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Chemical reactions happen most readily when energy is _______________during the reaction.
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Molecules with ________________of chemical potential energy are__________________than
ones with __________________________ chemical potential energy.
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Energy will be __________________________when the reactants have _________________
chemical potential energy than the products.
Exothermic Processes
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When a change results in the release of energy it is called an __________________ process.
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An exothermic chemical reaction occurs when the reactants have __________________
chemical potential energy than the products.
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The excess energy is released into the surrounding materials, ______________ energy to them.
 Often the surrounding materials get hotter from the energy released by the reaction.
Endothermic Processes
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When a change requires the absorption of energy it is called an___________________ process.
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An endothermic chemical reaction occurs when the products have ________________chemical
potential energy than the reactants.
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The required energy is ____________ from the surrounding materials, taking energy from them.
Often the surrounding materials get colder due to the energy being removed by the reaction.
_____________________
Temperature
The average___________________________of an object!!
Temperature Scales
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____________________scale, °F.
Used in the U.S.
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___________________scale, °C.
Used in all other countries.
 A Celsius degree is 1.8 times larger than a Fahrenheit degree.
____________________scale, K.
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Absolute scale.
Temperature Scales
100°C
373 K
212°F
Boiling
point water
25°C
298 K
75°F
Room temp
0°C
273 K
32°F
-38.9°C
234.1 K
-38°F
Melting
point ice
Boiling
point
mercury
-183°C
90 K
-297°F
-269°C
-273°C 4 K
0 K -452°F
Celsius
Kelvin
Boiling
point
oxygen
BP helium
-459 °F Absolute zero
Fahrenheit
Temperature Scales
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The Fahrenheit temperature scale used as its two reference points the freezing point of
concentrated _______________ (0 °F) and average _________________temperature (96 °F).
 More accurate measure now sets average body temperature at 98.6 °F.
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Room temperature is about ____________________°F.
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The Celsius temperature scale used as its two reference points the freezing point of
_______________________(0 °C) and boiling point of _______________________ (100 °C).
 More reproducible standards.
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Most commonly used in science.
Room temperature is about ________________________°C.
The Kelvin Temperature Scale
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Both the Celsius and Fahrenheit scales have ___________________________numbers.
 Yet, real physical things are always positive amounts!
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The Kelvin scale is an absolute scale, meaning it measures the ___________________
temperature of an object.
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0 K is called_______________________. It is too cold for matter to exist because all
molecular motion would_______________________________.
 0 K = -273 °C = -459 °F.
 Absolute zero is a _______________value obtained by following patterns mathematically
Kelvin vs. Celsius
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The __________of a “degree” on the Kelvin scale is the _____________as on the Celsius scale.
 Although technically, we don’t call the divisions on the Kelvin scale degrees; we call
them_____________________________
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When converting between kelvins and °C, remember that the kelvin temperature is always the
____________________number and always _________________________!
K  C  273
Solve: Convert –25 °C to Kelvins
Energy and the Temperature of Matter
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The amount the ___________________of an object increases depends on the amount of
____________________ added (__________).
 If you_________ the added heat energy the temperature will increase _______as much.
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The amount the ________________of an object increases also depends on its_____________.
 If you _______________the mass, it will take ______________as much heat energy to
raise the temperature the ____________________ amount.
Heat Capacity
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Heat capacity is the _______________of heat a substance must absorb to______________
its temperature by__________________.
 cal/°C or J/°C.
 Metals have ____________heat capacities; insulators have __________heat capacities.
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Specific heat = heat capacity of __________________________of the substance.
 cal/g°C or J/g°C.
 Water’s specific heat = __________________________for liquid.
 Or___________________________.
It is less for ice and steam.
Specific Heat Capacity
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Specific heat is the amount of _______________required to raise the temperature of
_________________of a substance by________________________.
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The ___________________a material’s specific heat is, the_______________ energy it takes
to______________________ its temperature a given amount.
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Like density, specific heat is a _____________________________of the type of matter.
 It doesn’t matter how much material you have.
 It can be used to _________________________the type of matter.
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Water’s _____________________specific heat is the reason it is such a good cooling agent.
 It absorbs ___________________of heat for a relatively__________________ mass.
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The specific heat of water is 1 calorie per 1 gram per 1 degree Celsius
Fill in info on slide_____________________________________________________________
Joule = The energy used by 1 watt for 1 second
What is the distinction between heat capacity and specific heat capacity.
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Heat capacity is the quantity of heat required to change an _____________temperature by 1o C.
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The heat capacity of any particular object _______________________________of that
object (as well as with the type of material in that object).
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The heat capacity of a steel girder is ________________ than the heat capacity of a steel nail.
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Specific heat capacity ________________________with the mass of the object, but rather,
____________________________________________of the material in the object.
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Specific heat capacity is the quantity of heat required to raise the temperature
_______________________of a substance by 1oC.
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The specific heat capacities of the steel in the steel girder and the steel in the steel nail are
________________________(assuming the two steels are of the same composition).
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Specific heat capacity is a property of a particular ___________________; heat capacity is a
property of a particular______________________________.
Specific Heat
How ______________heats up or cools down is the ________________for all other materials.
There is usually an interest to how metals heat up. However, all materials heat up _____________.
1 calorie is defined as the amount of _______________needed to raise _____________of water
__________________Celsius
1 kg of water would take 1,000 calories for each degree. Our 700C increase would take
1,000 x 70 = 70,000 calories.
The same mass of different materials store different amounts of heat energy.
Water takes about _________________________to heat than aluminum, meaning it stores about
_____________________________ calories.
The same mass of different materials store different amounts of heat energy.
Water takes about ___________________________to heat than gold, meaning it stores about
_____________________________________at the same temperature!!!
Specific Heat Capacities
Substance
Specific Heat
J/g°C
Aluminum
0.903
Carbon (dia)
0.508
Carbon (gra)
0.708
Copper
0.385
Gold
0.128
Iron
0.449
Lead
0.128
Silver
0.235
Ethanol
2.42
Water (l)
4.184
Water (s)
2.03
Water (g)
2.02
Heat Gain or Loss by an Object
The amount of heat energy ____________________by an object depends on__________ factors:
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_______________________material there is
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_______________________the material is
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_______________________ the temperature changed.
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Amount of Heat = Mass x Specific Heat Capacity x Temperature Change
q = m x C x DT
Example 3.10:
•
Given:
Find:
Gallium is a solid metal at room temperature, but melts at 29.9 °C. If you hold gallium in your
hand, it melts from body heat. How much heat must 2.5 g of gallium absorb from your hand to
raise its temperature from 25.0 °C to 29.9 °C? The heat capacity of gallium is 0.372 J/g°C.
Equation:
Solution:
Sig figs & round:
Practice—Calculate the Amount of Heat Released When 7.40 g of Water Cools from 49° to 29 °C
Given:
Find:
Equation:
Solution:
Sig figs & round:
52.) If 72.4 kJ of heat is applied to a 952 g block of metal, the temperature of the metal increases by
10.7oC. Calculate the specific heat capacity of the metal in J/goC.
Given:
Find:
Equation:
Solution:
Sig figs & round:
53.) Calculate the energy required in joules and calories to heat 29.2 g of aluminum from 27.2 oC to 41.5
o
C. See data table 3.2
Given:
Find:
Equation:
Solution:
Sig figs & round:
54.) A particular sample of iron requires 562 J to raise its temperature from 25.0oC to 50.0oC. What
must be the mass of the sample of iron? See table 3.2
Given:
Find:
Equation:
Solution:
Sig figs & round:
55.) If 100. J of heat energy is applied to 25.0 g sample of mercury, by how many degrees will the
temperature of the mercury sample increase?
Given:
Find:
Equation:
Solution:
Sig figs & round:
A 35.0 gram lead ball at 25.0oC was heated with 40.5 joules of heat. What is the final temperature of
the lead? Use table for Sp. Heat capacity.
Given:
Find:
Equation:
Solution:
Sig figs & round:
Winter Survival and a Safe Source of Heat for Field Operations
Water: Pros and Cons: List ______________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Metal: Pros and Cons: List ___________________________________________________________________________________________________
Rocks: Pros and Cons: List _______________________________________________________
___________________________________________________________________________
EXTRA CREDIT: It’s February and you want to heat up your pool. It is currently 50oF (10oC) and you
want it raised to 80oF (27oC) Using an electric heater, how much will it cost if 1 kilowatt-hour is 10
cents? The pool is 7.0 meters long, 5.0 meters wide and 2.0 meters deep.
A. What’s the volume in cubic meters? ______
B. What is the volume in cubic centimeters?___________
C. What is the total grams of the water? ____________