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UNIT 3
CHAPTER 5
Thermochemistry
LEARNING GOALS AND SUCCESS CRITERIA
Analyze technologies and chemical processes that are based on energy
changes, and evaluate them in terms of their efficiency and their effects on the
environment.
By the end of this lesson, I can…
•Use appropriate terminology related to energy changes and rates of
reactions
•Know the difference between kinetic and potential energy and endothermic
and exothermic reactions
THINK, PAIR, SHARE
Answer the following questions individually, then share with your partner. Come up
with collaborative answers to share with the class.
•What is energy?
•What forms of energy do you use in your everyday life? Give at least 2 examples.
•What are some of the sources of this energy?
VIDEO
THE NATURE OF ENERGY – KEY WORDS
Thermochemistry
Energy
Work
Potential Energy
Kinetic Energy
Thermal Energy
Heat
Temperature
Exothermic
Endothermic
KINETIC VS POTENTIAL ENERGY
Kinetic Energy – the energy of an object due to its motion
Potential Energy – the energy of a body or system due to its position or composition
TASK
For each of the following, describe which is greater – the potential energy or the
kinetic energy.
(A) A stick of dynamite prior to exploding
(B) A space shuttle before launch
(C) When the light switch is turned on
Write down two examples of kinetic and potential energy.
THERMAL ENERGY, HEAT AND TEMPERATURE
Thermal energy is the total quantity of kinetic and potential energy in a substance.
Heat is the transfer of thermal energy from a warm object to a cooler object.
Temperature is a measure of the average kinetic energy of entities in a substance.
TASK – THINK IT THROUGH
What is the difference between heat and temperature?
What is the difference between thermal energy and temperature?
HEAT VS TEMPERATURE
THERMAL ENERGY VS TEMPERATURE
THE LAW OF CONSERVATION OF ENERGY
Energy cannot be created or destroyed
Energy is always conserved.
We cannot create new energy nor can we destroy it
Energy can only be converted from from one form to another
EXOTHERMIC AND ENDOTHERMIC REACTIONS
Exothermic reaction releases energy to the surroundings
Endothermic reaction absorbs energy from the surroundings.
TASK
For each of the following, identify whether the reaction process is exothermic or
endothermic.
(A) water evaporating into steam
(B) a candle burning
(C) the melting of ice
(D) dissolving barium hydroxide in water and observing a temperature decrease in
the surroundings
LEARNING GOALS AND SUCCESS CRITERIA
Analyze technologies and chemical processes that are based on energy
changes, and evaluate them in terms of their efficiency and their effects on the
environment.
By the end of this lesson, I can…
•Use appropriate terminology related to energy changes and rates of
reactions
•Know the difference between kinetic and potential energy and endothermic
and exothermic reactions