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CH104 Chapter 2: Energy & Matter Heating & Cooling Curves
Temperature Energy in Reactions Specific Heat Energy from Food States of Matter Heating & Cooling Curves
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Chapter 2 Energy and Matter
2.2 Temperature
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Units of Measurement Metric SI Common Conversions Length Volume Mass
Temperature meter (m) m = 1.09 yd liter (L) L = 1.06 qt gram (g) kg = 2.2 lb Celsius (oC) C = (F-32)/1.8 Kelvin (K) K = C + 273
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Temperature 180 o 100 o
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Learning Check A. What is the temperature of freezing water? 1) 0 °F 2) 0 °C 3) 0 K B. What is the temperature of boiling water? 1) 100 °F 2) 32 °F 3) 373 K C. How many Celsius units are between the boiling and freezing points of water? 1) 100 2) 180 3) 273
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Solution A. What is the temperature of freezing water? 1) 0 °F 2) 0 °C 3) 0 K B. What is the temperature of boiling water? 1) 100 °F 2) 32 °F 3) 373 K C. How many Celsius units are between the boiling and freezing points of water? 1) 100 2) 180 3) 273
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Trivial Pursuit Question
At what temperature does oF = oC? - 40 oF = - 40 oC - 40 o
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Temperature conversion
Common scales used Fahrenheit, Celsius and Kelvin. oF = 1.8 oC + 32 oC = (oF - 32) 1.8 K = oC + 273 SI unit
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Solving a Temperature Problem
A person with hypothermia has a body temperature of 34.8 °C. What Is that temperature in °F? F = 1.8(C) ° F = (1.8)(34.8 °C) ° exact tenth’s exact = 62.6 ° ° = 94.6 °F tenth’s
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Practice: Temp Conversion
What is 75.0 º F in ºC? ºC = (75.0 º F -32 º) = 23.9 ºC 1.8 What is -12 º F in ºC? º F = 1.8 (-12) + 32 º F = 10 º C
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Learning Check The normal temperature of a chickadee is °F. What is that temperature on the Celsius scale? 1) 73.8 °C 2) 58.8 °C 3) 41.0 °C
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Solution The normal temperature of a chickadee is °F. What is that temperature on the Celsius scale? 1) °C 2) °C 3) °C TC = TF – 32 ° 1.8 = (105.8 – 32 °) = 73.8 °F = 41.0 °C 1.8 ° tenth’s place
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Learning Check A pepperoni pizza is baked at 455 °F. What temperature is needed on the Celsius scale? 1) 423 °C 2) 235 °C 3) 221 °C
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Solution A pepperoni pizza is baked at 455 °F. What temperature is needed on the Celsius scale? 1) 423 °C 2) 235 °C 3) 221 °C TF – 32 ° = TC 1.8 (455 – 32 °) = 235 °C 1.8 one’s place
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Learning Check On a cold winter day, the temperature is –15 °C. What is that temperature in °F? 1) 19 °F 2) 59 °F 3) 5 °F
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Solution On a cold winter day, the temperature is –15 °C.
What is that temperature in °F? 1) 19 °F 2) 59 °F 3) 5 °F TF = 1.8TC ° TF = 1.8(–15 °C) + 32 ° = – ° = 5 °F one’s place Note: Be sure to use the change sign key on your calculator to enter the minus (–) sign. 1.8 x 15 +/ – = –27
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Temperatures
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Learning Check What is normal body temperature of 37 °C in kelvins?
1) 236 K 2) 310 K 3) 342 K
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Solution What is normal body temperature of 37 °C in kelvins?
1) 236 K 2) 310 K 3) 342 K TK = TC = 37 °C = 310. K one’s place
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Chapter 2 Energy and Matter
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Energy Energy = The capacity to cause change Heat Light Wind
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Potential Energy = stored Energy
(Has potential for motion) X Kinetic Energy = Energy in motion (Fulfilling its potential)
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Learning Check Identify each of the following as potential energy or kinetic energy. A. roller blading B. a peanut butter and jelly sandwich C. mowing the lawn D. gasoline in the gas tank
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Solution Identify each of the following as potential energy or kinetic energy. A. roller blading kinetic B. a peanut butter and jelly sandwich potential C. mowing the lawn kinetic D. gasoline in the gas tank potential
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Kinetic Energy KE = 1 mv2 2 Which has more E? Truck moving at 5 mph
Bicycle moving at 5 mph
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Units of Measurement Metric SI Common Conversions Length Volume Mass
Temperature Energy meter (m) m = 1.09 yd liter (L) L = 1.06 qt gram (g) kg = 2.2 lb Celsius (oC) C = (F-32)/1.8 Kelvin (K) K = C + 273 calorie (cal) 1Kcal = 1000 cal = 1Cal Joule (J) cal = 4.18 J
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Examples of Energy Values in Joules
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Learning Check How many calories are obtained from a pat of butter if it provides 150 J of energy when metabolized?
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Solution How many calories are obtained from a pat of butter if it provides 150 J of energy when metabolized? Given Need 150 J 1 cal 4.184 J = cal 36 Conversion Factors: 1 cal and J 4.184 J cal
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Chapter 2 Energy and Matter
2.3 Specific Heat
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Energy Units of Energy = calorie cal kilocalorie kcal
1000 cal = 1 kcal Calorie Cal Cal = kcal joule J 4.18 J = 1 cal British Thermal Unit BTU
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Energy calorie: E to raise 1 g H20 by 1 oC Specific Heat H2O 1 cal
1g 1oC 1oC
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Examples of Specific Heats
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Specific Heat E to raise Temp of 1g substance by 1 oC H2O 1.00 cal
g oC H2O 1.00 Fe 0.11 Cu 0.093 Ag 0.057 Au 0.031 Al 0.22 Sand 0.19 Add 1 cal 0oC = start
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Specific Heat E to raise Temp of 1g substance by 1 oC H2O 1.00 30o Au
0.031 cal g oC Ag 0.057 20o Cu 0.093 10o Fe 0.11 Sand 0.19 Al 0.22 1o H2O 1.00 Add 1 cal 0oC = start
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Specific Heat H2O 1.00 30o Au 0.031 Low SpHt; Heats quickly Ag 0.057
Cu 0.093 10o Fe 0.11 Sand 0.19 Al 0.22 1o H2O 1.00 High SpHt; Resists change
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Resists change in body temp
Specific Heat Dehydrated person Body temp rises quickly Hydrated person Resists change in body temp Heats quickly Gets hot Sand 0.19 H2O 1.00 Resists change Stays cold
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Learning Check A. For the same amount of heat added, a substance with a large specific heat 1) has a smaller increase in temperature 2) has a greater increase in temperature B. When ocean water cools, the surrounding air 1) cools 2) warms 3) 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 ) low specific heat
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Solution A. For the same amount of heat added, a substance with a large specific heat 1) has a smaller increase in temperature 2) has a greater increase in temperature B. When ocean water cools, the surrounding air 1) cools 2) warms 3) 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 ) low specific heat
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Specific Heat 24.8g Sample Problem:
What is the specific heat of a metal if 24.8 g absorbs 65.7 cal of energy and the temp rises from 20.2 C to 24.5 C? 65.7 0.62 cal g oC = cal 24.8g 4.3oC = cal 1g 1oC SpHt = 24.5oC DT = 4.3 Co m = 24.8g 20.2oC
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Specific Heat E = m DT SpHt
Sample Problem: How much energy does is take to heat 50 g’s of water from 75oC to 87oC? 87oC DT = 12 Co m = 50g H2O 75oC 1 cal 1g 1oC SpHt =
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Specific Heat E = m DT SpHt
Sample Problem: How much energy does is take to heat 50 g’s of water from 75oC to 87oC? m DT SpHt 12 Co 1 cal 1g 1oC 50g H2O = cal to heat water 600
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Specific Heat E = m DT SpHt 750g H2O Sample Problem:
A hot-water bottle contains 750 g of water at 65 °C. If the water cools to body temp (37 °C), how many calories of heat could be transferred to sore muscles? 65oC DT = 28 Co m = 750g H2O 37oC 1 cal 1g 1oC SpHt =
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Specific Heat E = m DT SpHt 750g H2O = cal 21000 Sample Problem:
A hot-water bottle contains 750 g of water at 65 °C. If the water cools to body temp (37 °C), how many calories of heat could be transferred to sore muscles? m DT SpHt 28 Co 1 cal 1g 1oC 750g H2O = cal from cool water 21000
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Learning Check How many kilojoules are needed to raise the
temperature of 325 g of water from 15.0 °C to 77.0 °C?
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Solution E = m DT SpHt How many kilojoules are needed to raise the
temperature of 325 g of water from 15.0 °C to 77.0 °C? m DT SpHt = KJ 84.3 62 Co 4.184 J 1g 1oC 1 KJ 1000 J 325g H2O 77oC DT = 62 Co 15oC
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Chapter 2 Energy and Matter
2.4 Energy and Nutrition 1 Cal = 1000 calories 1 Cal = 1 kcal 1 Cal = J 1 Cal = kJ
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Energy Units of Energy = 1 Cal 1000 cal = 1 kcal 1 cal = 4.18 J 1 Cal
4184 J = kJ
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Calorimeters A calorimeter
A reaction chamber & thermometer in H2O used to measure heat transfer indicates the heat lost by a sample indicates the heat gained by water
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Energy from Food 4 kcal g 17 kJ g Carbohydrate 9 kcal g 38 kcal g Fat
Protein 4 kcal g 17 kcal g
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Calories in Some Foods Energy Requirements
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Energy from Food Sample Problem:
How much energy in kcal (= Cal) would be obtained from 2 Tbl peanut butter containing 6 g carb, 16 g fat, & 7 g protein? 6 g carb 4 kcal 1 g carb = 24 kcal = 196 kcal = 196 Cal 16 g fat 9 kcal 1 g fat = 144 kcal = 200 Cal 7 g protein 4 kcal 1 g protein = 28 kcal
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Learning Check A cup of whole milk contains 12 g of carbohydrate, 9.0 g of fat, and 9.0 g of protein. How many kcal (Cal) does a cup of milk contain? (Round to the nearest 10 kcal.)
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Solution A cup of whole milk contains 12 g of carbohydrate, 9.0 g of fat, and 5.0 g of protein. How many kcal (Cal) does a cup of milk contain? (Round to the nearest 10 kcal.) 12 g carb 4 kcal 1 g carb = 48 kcal = 149 kcal = 149 Cal 9 g fat 9 kcal 1 g fat = 81 kcal = 150 Cal 5 g protein 4 kcal 1 g protein = 20 kcal
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Chapter 2 Energy and Matter
2.5 Classification of Matter
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Matter Weight on earth. The stuff things are made of.
Has Mass and takes up space. (Air, water, rocks, etc..) The amount of stuff (in g’s) (Bowling Ball > Balloon) Matter: The stuff things are made of. Has Mass and takes up space. Mass: The amount of stuff. Usually measured in grams. Bowling ball has more mass than Weight on earth. Weight on earth. Pull of Gravity on matter.
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Classification of matter
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Classification of matter
Pure Substance Mixture Element Compound Fe FeS Fe + S Mg MgO Mg + O2
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Non-uniform composition
Mixtures Mixture Homogeneous (Solution) Heterogeneous Non-uniform composition Uniform composition Pizza Gasoline Tea w/ice Air Fe + S Urine Sand
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Physical Separation of A Mixture
Mixtures can be separated involves only physical changes Like Filtering & distilling Like when pasta and water are separated with a strainer
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Classification of Matter
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Learning Check Identify each of the following as a pure substance or a mixture. A. pasta and tomato sauce B. aluminum foil C. helium D. Air
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Solution Identify each of the following as a pure substance or a mixture. A. pasta and tomato sauce mixture B. aluminum foil pure substance C. helium pure substance D. Air mixture
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Learning Check Identify each of the following as a homogeneous or heterogeneous mixture. A. hot fudge sundae B. shampoo C. sugar water D. peach pie
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Solution Identify each of the following as a homogeneous or heterogeneous mixture. A. hot fudge sundae heterogeneous B. Shampoo homogeneous C. sugar water homogeneous D. peach pie heterogeneous
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Chapter 2 Energy and Matter
2.6 States and Properties of Matter
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Elemental states at 25oC Solid Liquid Gas H He Li Be B C N O F Ne Na
Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba Ls Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 6 - 2 2
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Properties of matter Solids, liquids and gases can easily be recognized by their different properties. Density The mass of matter divided by it’s volume. Shape Is it fixed or take the shape of the container? Compressibility If we apply pressure, does the volume decrease? Thermal expansion How much does the volume change when heated? 3
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Properties of matter High High Large Physical State Solid Liquid Gas
Property High like solids High Density Shape Compressibility Thermal expansion Low expands to fill container Fixed Shape of container Large Small Small Very small Moderate Small 4
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Summary of the States of Matter
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Three States of Water
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Hydrogen Bonding of Water
Frozen H2O: Slow moving molecules H-Bond in patterns
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Learning Check Identify each as a S) solid, L) liquid, or G) gas.
__ A. It has a definite volume but takes the shape of the container. __ B. Its particles are moving very rapidly. __ C. It fills the volume of a container. __ D. It has particles in a fixed arrangement. __ E. It has particles that are close together and are mobile.
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Solution Identify each as a S) solid, L) liquid, or G) gas.
L A. It has a definite volume but takes the shape of the container. G B. Its particles are moving very rapidly. G C. It fills the volume of a container. S D. It has particles in a fixed arrangement. L E. It has particles that are close together and are mobile.
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Physical Properties of Copper
are observed or measured without changing the identity of a substance include shape and color include melting point and boiling point Physical Properties of Copper
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Physical Change In a physical change,
the identity and composition of the substance do not change the state can change or the material can be torn into smaller pieces
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Examples of Physical Change
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Chemical Properties Chemical properties
describe the ability of a substance to change into a new substance
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Chemical Change During a chemical change,
reacting substances form new substances with different compositions and properties a chemical reaction takes place Iron Fe Iron (III) oxide Fe2O3
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Examples of Chemical Change
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Summary
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Learning Check Classify each of the following as a 1) physical change or 2) chemical change. A. ____ burning a candle B. ____ ice melting on the street C. ____ toasting a marshmallow D. ____ cutting a pizza E. ____ polishing a silver bowl
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Solution Classify each of the following as a
1) physical change or 2) chemical change. A. ____ burning a candle 2) chemical B. ____ ice melting on the street 1) physical C. ____ toasting a marshmallow 2) chemical D. ____ cutting a pizza 1) physical E. ____ polishing a silver bowl 2) chemical
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Chapter 2 Energy and Matter
2.7 Changes of State
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Condense Vaporize Melt Freeze
Changes of State Fast, far apart, Random Vapor Condense Vaporize Boiling Pt Moderate, close, Random arrangement Liquid Melting Pt = Freezing Pt Melt Freeze Slow, close, Fixed arrangement Solid
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Changes of State Vapor Deposit Frost Liquid Sublime Freeze Dry Solid
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Heating Curve Specific Heat of Steam Heat of Vaporization
0.48 cal to heat vapor g o C Heat of Vaporization 540 cal to vaporize water g Specific Heat of H2O 1.00 cal to heat water g o C Heat of Fusion 80 cal to melt ice g Specific Heat of Ice 0.50 cal to heat ice g o C
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Heating Curve 0.48 cal to heat vapor g o C 540 cal to vaporize water g
1.00 cal to heat water g o C 80 cal to melt ice g 0.50 cal to heat ice g o C
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Example: Calculate the total amount of heat needed to change 500
Example: Calculate the total amount of heat needed to change 500. g of ice at –10 oC into 500. g of steam at 120oC. 500g 20 o C cal g o C = 4800 cal to heat vapor 500g cal g = 270,000 cal to vaporize water 500g 100 o C cal g o C = 50,000 cal to heat water 500g cal g = 40,000 cal to melt ice 500g 10 o C cal g o C = 2500 cal to heat ice 367,300 cal = 3.67 x 105 cal
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Learning Check A. A plateau (horizontal line) on a heating curve represents 1) a temperature change 2) a constant temperature 3) a change of state B. A sloped line on a heating curve represents
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Solution A. A plateau (horizontal line) on a heating curve represents
1) a temperature change 2) a constant temperature 3) a change of state B. A sloped line on a heating curve represents
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Learning Check Use the cooling curve for water to answer each.
A. Water condenses at a temperature of 1) 0 °C 2) 50 °C 3) 100 °C B. At a temperature of 0 °C, liquid water 1) freezes 2) melts 3) changes to a gas C. At 40 °C, water is a 1) solid 2) liquid 3) gas D. When water freezes, heat is 1) removed 2) added
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Solution Use the cooling curve for water to answer each.
A. Water condenses at a temperature of 1) 0 °C 2) 50 °C 3) 100 °C B. At a temperature of 0 °C, liquid water 1) freezes 2) melts 3) changes to a gas C. At 40 °C, water is a 1) solid 2) liquid 3) gas D. When water freezes, heat is 1) removed 2) added
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Learning Check To reduce a fever, an infant is packed in 250 g of ice. If the ice (at 0 °C) melts and warms to body temp (37.0 °C), how many calories are removed?
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Solution To reduce a fever, an infant is packed in 250 g of ice. If the ice (at 0 °C) melts and warms to body temp (37.0 °C), how many calories are removed? 37.0 °C 250g o C cal g o C = 9,250 cal to heat water STEP 2 250g cal g = 20,000 cal to melt ice 0.0 °C STEP 1 29,000 cal = 2.9 x 104 cal
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