Presentation on theme: "2 Temperature Temperature is a measure of how hot or cold an object is Ice Water0 o C32 o F273 o K Boiling Water100 o C 212 o F373 o K Room Temp 20 o."— Presentation transcript:
Temperature Temperature is a measure of how hot or cold an object is Ice Water0 o C32 o F273 o K Boiling Water100 o C 212 o F373 o K Room Temp 20 o C 68 o F293 o K Body Temp 37 o C99 o F 310 o K Absolute Zero-273 o C -459 o F0 o K F = 9/5 C + 32 K = C + 273
Pressure and Temperature Boiling WaterIce Water Pressure GageConstant Air Volume 0 o C100 o C Pressure DecreasesPressure Increases
Absolute Zero Ice Water273 o K Boiling Water373 o K Absolute Zero 0 o K Temperature ( o C) 0 o C100 o C-273 o C
Quantity of Heat Quantity of Heat = Mass x Specific Heat x Temperature Change Q = m c ΔT 1 calorie is the amount of heat energy necessary to raise 1 gram of water 1 celsius degree. Specific Heat (Capacity) is the amount of heat energy necessary to raise 1 gram of a substance 1 celsius degree. 1 calorie = 4.18 joules 1 Calorie = 1,000 calories = 4,180 joules
Calorimetry Hot Object Cold Object Heat Loss = Heat Gain m H c H ΔT H = m C c C ΔT C Heat Flow m H = mass of hot object c H = specific heat of hot object ΔT H = temperature change of hot object m C = mass of cold object c C = specific heat of cold object ΔT C = temperature change of cold object
Sample Problem 1 m H = 500 g T H = 90.0 o C C H =.30 cal/g o C m C = 200 g T C = 10.0 o C C C = 1.0 cal/g o C T E = ? Heat Loss = Heat Gain m H c H ΔT H = m C c C ΔT C 500(.30)(90- T E ) = 200(1.0)(T E - 10) 150 (90- T E ) = 200 (T E - 10) 13500- 150T E = 200 T E - 2000 350T E = 15,500 T E = 44.3 o C Hot Object Cold Object Heat Flow 500 g of metal at 90.0 o C is placed in 200 g of water at 10.0 o C. The specific heat capacity of the metal is.30 cal/g o C. What is the final equilibrium temperature of the water and metal?
Sample Problem 2 m H = 800 g T H = 100.0 o C m C = 200 g T C = 10.0 o C T E = 40.0 o C C C = 1.00 cal/g o C C H = __ cal/g o C Heat Loss = Heat Gain m H c H ΔT H = m C c C ΔT C 800 (C H )(100- 40) = 200(1.0)(40 - 10) 48,000 (C H ) = 6,000 C H =.125 cal/g o C Cold Water Hot Metal 800 g of metal at 100.0 o C is placed in 200 g of water at 10.0 o C. The final equilibrium temperature of the water plus metal is 40.0 o C. What is the specific heat capacity of the metal ?
Linear Expansion LoLo ΔL ΔL = is proportional to ΔT ΔL = is proportional to L o ΔL = depends on the type of material
Volume Expansion ΔV = is proportional to ΔT ΔV = is proportional to V o ΔV = depends on the type of material
Linear Expansion 1.Aluminum 2.4 cm per km 2.Brass 2.0 cm per km 3.Copper 1.7 cm per km 4.Steel 1.2 cm per km 5.Glass 0.4-0.9 cm per km The following materials are listed in alphabetical order. Arrange them in order of their rate of linear expansion per o C from lowest to highest. Aluminum Brass Copper Glass Steel
Conductivity THTH TCTC H L H increases as (T H – T C ) increases H = depends on the type of material H decreases as L increases H is the heat flow between hot (T H ) and cold ( T C ) objects
Top 7 Conductors of Heat 1.Silver 406 2.Copper 385 3.Aluminum 205 4.Brass 109 5.Steel 50 6.Lead 35 7.Mercury 8 Aluminum Brass Copper Lead Mercury Silver Steel The following metals are listed in alphabetical order. Arrange them in order of conductivity from best to worst.
Top 10 Heat Insulators 1.Styrofoam.01 2.Air.024 3.Cork.04 4.Felt.04 5.Fiberglass.04 6.Rock Wool.04 7.Wood.12 8.Brick.6 9.Concrete.8 10.Glass.9 Air Brick Concrete Cork Felt Fiberglass Glass Rock Wool Styrofoam Wood The following insulators are listed in alphabetical order. Arrange them in order of insulation from best to worst.
Sea Breezes and Convection Currents Day During the day, the land is hotter and the air rises above the land and is replaced by the cooler air from above the water. During the night, the land cools faster and the air rises above the warmer water and is replaced by the cooler air from above the land. Night
Radiation A good radiator of heat is a good absorber of heat. Dark colored objects radiate and absorb heat better than light colored objects. The rate of heat radiation increases with temperature. The rate of heat radiation or absorption is proportional to the surface area of the object radiating or absorbing.
Scaling and Heat Radiation S = 1 cm S= 10 cm S = 2 cm V= 8 cm 3 A = 24 cm 2 V= 1 cm 3 A= 6 cm 2 V= 1000 cm 3 A = 600 cm 2 A/V = 6 A/V =.6 A/V = 3
2 IceWater Steam Heat 80 calories added to 1 g of ice at 0 o C will convert the ice to 1gram of water at 0 o C. 540 calories added to 1 g of water at 100 o C will convert the water to 1gram of steam at 100 o C. Change of State
The Human Body -Thermodynamic System External WorkInternal Work Food Heat OutHeat In Energy Change = (Food +Heat In) – (External Work + Heat Out + Internal Work)
Thermodynamics and Weight Loss External Work Internal Work Food Heat Out Heat In Energy Change = Food + Heat In – External Work - Heat Out - Internal Work If Energy Change > 0, then you gain weight.If Energy Change < 0, then you lose weight. If 1 once fat is equivalent to approximately 300 Calories of energy, we can calculate weight loss on a daily or monthly basis based on ΔU value. If Energy Change = 0, then you maintain your body weight.