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? Energy is the ability to do work Electrical – electrical outlets, lightening motion - Moving things have energy. The faster something is moving, the more energy it has. sound - the more sound energy it has. Thermal - A cup of hot chocolate is warmer than a glass of cold chocolate milk. Light - sunlight Chemical energy - We all get energy from the food we eat. The form of energy that is in food is called chemical energy. Our bodies use this energy to grow and move. Also batteries!
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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? Thermal energy – total kinetic and potential energy Temperature is the average kinetic energy
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