Bell work Tuesday Draw the following table onto your bellwork sheet and fill in the boxes that you already know. Properties Solid Liquid Gas Amount of movement of particles Amount of energy in particles Example of Substance Drawing of Particles in the Substance

CHEMISTRY Thermochemistry Chapter 17 Part 1

17.1 Thermochemistry Thermochemistry is concerned with the heat changes that occur during chemical reactions.

Energy - the capacity for doing work or supplying heat Energy - the capacity for doing work or supplying heat. -Energy comes in many forms. -Kinetic Energy: the motion of particles -Potential Energy: stored energy Example When gasoline burns, the potential energy stored in its chemical bonds is released as KE to do work, such as a moving car.

Question A student is heating water to cook pasta. She notices it begins to boil at 100°C. What is the temperature of the water if she keeps boiling it for 15 more minutes?

Write potential or kinetic beside each of the following. Question Write potential or kinetic beside each of the following. A stretched rubber band ___________ A cookie ___________ A glass on a shelf ___________ A falling leaf ___________

Heat (q) - energy that is transferred from one object to another because of a temperature difference between them. Heat always flows from a warmer object to a cooler object. Heat cannot be measured directly.

In chemistry, we take the system’s point of view In chemistry, we take the system’s point of view. *The system is the part of the universe on which you focus your attention. *The surroundings are everything else in the universe. The chemical reaction in the tube is the system. Everything else is the surroundings.

Law of Conservation of Energy In any chemical or physical process, energy is neither created nor destroyed. Ex. Heat may be lost by the system, but it is not destroyed. It is transferred to the surroundings.

Endothermic process - system absorbs(gains) heat from the surroundings Endothermic process - system absorbs(gains) heat from the surroundings. Exothermic process - system releases(loses) heat to the surroundings.

Endothermic Exothermic Endothermic Exothermic Endothermic Exothermic Endothermic or exothermic process? -evaporating alcohol -leaves burning -boiling water -water cooling -melting ice -freezing water Endothermic Exothermic Endothermic Exothermic Endothermic Exothermic

Energy units: calorie (cal) and joule (J) calorie - quantity of heat needed to raise the temperature of one gram of water 1oC. 4.18 joule = 1 calorie

A food Calorie is used in nutrition and is capitalized *A food Calorie is used in nutrition and is capitalized. 1 Calorie = 1000 cal = 1 kcal Ex. If a label on a candy bar indicates it contains 180 Calories, that is really 180 kcal, or 180,000 calories! If "burned", the sugar and fat in the candy bar release 180,000 cal of energy.

These are capital Calories, so a serving of this food would give you 690 Calories, or 690,000 calories or 690 kilocalories. That is a lot of energy!!!

Heat capacity- amount of heat needed to raise the temperature of an object 1oC. It depends on the mass and composition of the substance. Ex. It takes more heat to increase the temperature of a large pot of water than a small cup of water. It takes more heat to raise the temperature of water than metal.

Question What has a higher heat capacity, water or Al metal? Explain your answer.