Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 1 Chapter 5 Energy and States of Matter 5.1 Energy 5.2 Measuring Heat 5.3 Energy and Nutrition

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 2 Energy Makes objects move. Makes things stop. Is needed to “do work.” Energy

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 3  Work is done when  You go up stairs.  You play soccer.  You lift a bag of groceries.  You ride a bicycle.  You breathe.  Your heart pumps blood.  Water goes over a dam. Work

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 4 Potential energy is energy that is stored for use at a later time. Examples are:  Water behind a dam  A compressed spring  Chemical bonds in gasoline, coal, or food Potential Energy

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 5 Kinetic energy is the energy of motion. Examples are:  Hammering a nail  Water flowing over a dam  Working out  Burning gasoline Kinetic Energy

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 6 Learning Check Identify the energy as 1) potential or 2) kinetic A. Roller blading. B. A peanut butter and jelly sandwich. C. Mowing the lawn. D. Gasoline in the gas tank.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 7 Solution Identify the energy as 1) potential or 2) kinetic A. Roller blading. (2 kinetic) B. A peanut butter and jelly sandwich. (1 potential) C. Mowing the lawn. (2 kinetic) D. Gasoline in the gas tank. (1 potential)

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 8 Energy has many forms:  Mechanical  Electrical  Thermal (heat)  Chemical  Solar (light)  Nuclear Forms of Energy

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 9  Heat energy flows from a warmer object to a colder object.  The colder object gains kinetic energy when it is heated.  During heat flow, the loss of heat by a warmer object is equal to the heat gained by the colder object. Heat

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 10  Heat is measured in calories or joules. 1 kilocalorie (kcal) = 1000 calories (cal) 1 calorie = 4.18 Joules (J) 1 kJ = 1000 J Some Equalities for Heat

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 11 Specific heat is the amount of heat (calories or Joules) that raises the temperature of 1 g of a substance by 1°C. Specific Heat

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 12 A. A substance with a large specific heat 1) heats up quickly2) heats up slowly B. When ocean water cools, the surrounding air 1) cools 2) warms3) stays the same C. Sand in the desert is hot in the day and cool at night. Sand must have a 1) high specific heat 2) low specific heat Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 13 A. A substance with a large specific heat 2) heats up slowly B. When ocean water cools, the surrounding air 2) warms C. Sand in the desert is hot in the day and cool at night. Sand must have a 2) low specific heat Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 14 When 200 g of water are heated, the water temperature rises from 10°C to 18°C. If 400 g of water at 10°C are heated with the same amount of heat, the final temperature would be 1) 10 °C2) 14°C 3) 18°C 200 g 400 g Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 15 When 200 g of water are heated, the water temperature rises from 10°C to 18°C. If 400 g of water at 10°C are heated with the same amount of heat, the final temperature would be 2) 14°C 200 g 400 g Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 16  To calculate the amount of heat lost or gained by a substance, we need the grams of substance, temperature change  T, and the specific heat of the substance.  Heat = g x °C x cal (or J) = cal ( or J) g °C Calculation with Specific Heat

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 17 A hot-water bottle contains 750 g of water at 65°C. If the water cools to body temperature (37°C), how many calories of heat could be transferred to sore muscles? The temperature change is 65°C - 37°C = 28°C. heat (cal) = g x  T x Sp. Ht. (H 2 O) 750 g x 28°C x 1.00 cal g°C = cal Sample Calculation for Heat

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 18 How many kcal are needed to raise the temperature of 120 g of water from 15°C to 75°C? 1) 1.8 kcal 2) 7.2 kcal 3) 9.0 kcal Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 19 How many kcal are needed to raise the temperature of 120 g of water from 15°C to 75°C? 2) 7.2 kcal 75°C - 15°C = 60 °C 120 g x (60°C) x 1.00 cal x 1 kcal g °C 1000 cal Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 20 On nutrition and food labels, the nutritional Calorie, written with a capital C, is used. 1 Cal is actually 1000 calories. 1 Calorie = 1 kcal 1 Cal = 1000 cal Energy and Nutrition

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 21 The caloric values for foods indicate the number of kcal provided by 1 g of each type of food. Caloric Food Values

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 22 Calories in Some Foods

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 23 Energy Requirements The amount of energy needed each day depends on age, sex, and physical activity.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 24 Loss and Gain of Weight If food intake exceeds energy use, a person gains weight. If food intake is less than energy use, a person loses weight.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 25 A cup of whole milk contains 12 g of carbohydrates, 9.0 g of fat, and 9.0 g of protein. How many kcal (Cal) does a cup of milk contain? 1) 48 kcal 2) 81 kcal 3) 165 kcal Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 26 3) 165 kcal 12 g carb x 4 kcal/g = 48 kcal 9.0 g fat x 9 kcal/g=81 kcal 9.0 g protein x 4 kcal/g=36 kcal Total kcal= 165 kcal Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 27 Chapter 5 Energy and States of Matter 5.4 States of Matter 5.5 Attractive Forces Between Particles

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 28  Solids have  A definite shape.  A definite volume.  Particles that are close together in a fixed arrangement.  Particles that move very slowly. Solids

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 29  Liquids have  An indefinite shape, but a definite volume.  The same shape as their container.  Particles that are close together, but mobile.  Particles that move slowly. Liquids

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 30  Gases have  An indefinite shape.  An indefinite volume.  The same shape and volume as their container.  Particles that are far apart.  Particles that move fast. Gases

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 31 Summary of the States of Matter

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 32 Identify each as: 1) solid 2) liquid or 3) gas. ___ A. It has a definite volume, but takes the shape of the container. __ B. Its particles are moving rapidly. __ C. It fills the volume of a container. __ D. It has particles in a fixed arrangement. __ E. It has particles close together that are mobile. Learning Check

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 33 Identify each as: 1) solid 2) liquid or 3) gas. 2 A. It has a definite volume, but takes the shape of the container. 3 B. Its particles are moving rapidly. 3 C. It fills the volume of a container. 1 D. It has particles in a fixed arrangement. 2 E. It has particles close together that are mobile. Solution

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 34 Attractive Forces between Particles In ionic compounds, ionic bonds are strong attractive forces that hold positive and negative ions together.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 35 Attractive Forces between Particles In covalent compounds, polar molecules exert attractive forces called dipole-dipole attractions. Hydrogen bonds are strong dipole attractions between hydrogen atoms and atoms of F, O, or N, which are very electronegative.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 36 Attractive Forces between Particles Nonpolar molecules form liquids or solids through weak attractions called dispersion forces. Dispersion forces are caused by temporary dipoles that develop when electrons are not distributed equally.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 37 Melting Points and Attractive Forces Ionic compounds require large amounts of energy to break apart ionic bonds. Thus, they have high melting points. Hydrogen bonds are the strongest type of dipole- dipole attractions. They require more energy to break than other dipole attractions. Dispersion forces are weak interactions and very little energy is needed to change state.

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 38 Melting Points and Attractive Forces of Some Typical Substances

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 39 Learning Check Identify the type of attractive forces for each: 1) ionic 2) dipole-dipole 3) hydrogen bonds 4) dispersion A. NCl 3 B. H 2 O C. Br-Br D. KCl E. NH 3

Copyright © 2004 Pearson Education Inc., publishing as Benjamin Cummings. 40 Solution Identify the type of attractive forces for each: 1) ionic 2) dipole-dipole 3) hydrogen bonds4) dispersion 2 A. NCl 3 3 B. H 2 O 4 C. Br-Br 1 D. KCl 3 E. NH 3