LecturePLUS Timberlake1 Chapter 6 Energy and States of Matter Heating and Cooling Curves From: PPT%20Energy/Heating%20Curves.ppt

LecturePLUS Timberlake2 Heating Curve for Water 120 °C steam 100 °C water  steam 50°C liquid water 0 °C ice  liquid -10 °C ice Heat added 

LecturePLUS Timberlake3 Learning Check CS1 A. The flat lines on a heating curve represent 1) a temperature change 2) a constant temperature 3) a change of state B. The sloped lines on a heating curve represent 1) a temperature change 2) a constant temperature 3) a change of state

LecturePLUS Timberlake4 Solution CS1 A. The flat lines on a heating curve represent 2) a constant temperature 3) a change of state B. The sloped lines on a heating curve represent 1) a temperature change

LecturePLUS Timberlake5 Temperature Changes T(1) beginning temp.1  T(1) T(f) final temp of both T°C  T(2) T(2) final temp. 2

LecturePLUS Timberlake6 Cooling Curve Using the heating curve of water as a guide, draw a cooling curve for water beginning with steam at 110°C and ending at -20°C.

LecturePLUS Timberlake7 Learning Check CS2 A. Water condenses at a temperature of 1)0°C2) 50°C3) 100°C B. At a temperature of 0°C, water 1) freezes2) melts3) changes to a gas C. When a gas condenses, heat is 1) released2) absorbed D. Freezing is 1) endothermic2) exothermic

LecturePLUS Timberlake8 Solution CS2 A. Water condenses at a temperature of 3) 100°C B. At a temperature of 0°C, water 1) freezes2) melts C. When a gas condenses, heat is 1) released D. Freezing is 2) exothermic

LecturePLUS Timberlake9 Learning Check CS3 Is energy absorbed (1) or released (2) in each of the following: ____A. Ice to liquid water ____B. Water vapor to rain ____C. Water to ice When it rains, the air becomes 1) warmer2) cooler3) does not change

LecturePLUS Timberlake10 Solution CS3 Is energy absorbed (1) or released (2) in each of the following: _1__A. Ice to liquid water _2__B. Water vapor to rain _2__C. Water to ice When it rains, the air becomes 1) warmer

LecturePLUS Timberlake11 Learning Check CS4 Complete using the terms gains or loses In the cooling coils of a refrigerator, liquid Freon ___________ heat from the food and changes to a gas Food ___________heat and becomes colder In the back of the refrigerator, Freon _________ heat and condenses back to a liquid

LecturePLUS Timberlake12 Solution CS4 Complete using the terms gains or loses In the cooling coils of a refrigerator, liquid Freon absorbs heat from the food and changes to a gas Food loses heat and becomes colder In the back of the refrigerator, Freon loses heat and condenses back to a liquid

LecturePLUS Timberlake13 Combining Heat Calculations To reduce a fever, an infant is packed in 1250 g of ice. If the ice at 0°C melts and warms to body temperature (37.0°C) how much heat in joules is absorbed?

LecturePLUS Timberlake14 Combining Heat Calculations Step 1: Diagram the change of state 37°C  T = 37.0°C - 0°C = 37.0°C 0°C S L

LecturePLUS Timberlake15 Step 2: Calculate the heat to melt ice (fusion) = 1250 g ice x 334 J 1 g ice = 418,000 J Step 3: Calculate the heat to warm the water from 0°C to 37°C = 1250 g x 37.0°C x 4.18 J g °C = 193,000 J

LecturePLUS Timberlake16 Total: Step 2 + Step 3 = 418,000 J + 193,000 J = 611,000 J

LecturePLUS Timberlake17 Learning Check CS8 A. Why do drops of liquid water form on a glass of iced tea ? B. When it snows, the air temperature seems warmer. How can that be? C. How much heat is needed to change 1.00 g of water at 0° to steam at 100°C? 1) 540 cal2) 640 cal 3) 720 cal

LecturePLUS Timberlake18 Solution CS8 A. Why do drops of liquid water form on a glass of iced tea? Condensation of water in the air that cools B. When it snows, the air temperature seems warmer. How can that be? Condensation is exothermic; heat is released. C. How much heat is needed to change 10.0 g of water at 0° to steam at 100°C? 2) 640 cal