Section 10.1 Energy, Temperature, and Heat Why Do Things Happen?

Section 10.1 Energy, Temperature, and Heat 1.To understand the importance and general properties of energy 2.To understand the concepts of temperature and heat 3.To understand the direction of energy flow as heat Objectives

Section 10.1 Energy, Temperature, and Heat

Section 10.1 Energy, Temperature, and Heat What is Energy? Kinetic, potential, thermal, gravitational, sound, elastic, light / electromagnetic, electrical, electrostatic energies are examples Energy is the driver of all changes. It flows between objects, it spreads out throughout the universe and in doing so is the driver of all observable phenomena (including chemical reactions)

Section 10.1 Energy, Temperature, and Heat Energy is the ability to do work or produce heat. A. The Nature of Energy Crane Lifting Doing Work: Explosion Producing Heat:

Section 10.1 Energy, Temperature, and Heat What is the difference between potential and kinetic energy?

Section 10.1 Energy, Temperature, and Heat Energy is the ability to do work or produce heat. Potential energy Energy of position Kinetic energy Energy of motion E = ½ mv 2 A. The Nature of Energy

Section 10.1 Energy, Temperature, and Heat A. The Nature of Energy Law of conservation of energy –Energy can be converted from one form to another but can neither be created nor destroyed. Bounce Ball Into Space

Section 10.1 Energy, Temperature, and Heat A. The Nature of Energy Law of conservation of energy in a chemical reaction –Energy can be converted from one form to another but can neither be created or destroyed. –Stored chemical energy of reactants is equal to energy of products plus energy given off –Some of the stored chemical energy of methane and oxygen is converted to heat as they react

Section 10.1 Energy, Temperature, and Heat Temperature is a measure of the random motions (kinetic energy) of the components of a substance. B. Temperature and Heat Hot waterCold water (90. o C) (10. o C) Fast Slow

Section 10.1 Energy, Temperature, and Heat Measuring Temperature

Section 10.1 Energy, Temperature, and Heat Heat transfer is a flow of energy between two objects due to a temperature difference between the objects. –Heat transfer is the way in which thermal energy is moved from a hot object to a colder object. B. Temperature and Heat Hot water Cold water (90. o C) (10. o C) Water Water (50. o C) (50. o C)

Section 10.1 Energy, Temperature, and Heat Heat Transfer The transition of thermal energy from a hotter to a cooler body Radiation Conduction Convection (Phase Change)

Section 10.1 Energy, Temperature, and Heat C. Exothermic and Endothermic Processes System – part of the universe on which we focus attention Surroundings – everything else in the universe Look at the example of burning a match:

Section 10.1 Energy, Temperature, and Heat C. Exothermic and Endothermic Processes Exothermic – heat energy flows out of the system Endothermic – heat energy flows into the system