18 Heat and the First Law of Thermodynamics Heat Capacity and Specific Heat Change of Phase and Latent Heat Joule’s Experiment and the First Law of Thermodynamics.

Slides:

Advertisements

Similar presentations

Heat naturally flows from high temperature to low temperature.

Advertisements

 State of Balance For the phase changes: As many molecules evaporating as there are condensing.

Temperature, Heat, & Combustion

Heat and Temperature PHYS 1090 Unit 4. Put Your Hands Together! (Activity 1) Doing work on your hands made them warmer. Adding energy raised the temperature.

Energy and Phases. Potential Energy - stored energy (stored in bonds, height) Kinetic Energy - energy of motion, associated with heat.

Heat Chapter 9 &10. Kinetic-molecular Theory Matter is made up of many tiny particles that are always in motion In a hot body the particles move faster.

Dr.Salwa Al Saleh Work and Heat Lecture 3.

Fig The net work done by the system in the process aba is –500 J.

Chapter 6 Energy and Chemical Reactions. Macroscale Kinetic Energy energy that something has because it is moving Potential Energy energy that something.

Whiteboard Work 1.The 2004 Tour de France’s Alpe d’Huez time trial was a climb with its finish 1200 m higher than the start. The winner, Lance Armstrong,

Thermal Force Unit 1.4.

Heat, Temperature, Heat Transfer, Thermal Expansion & Thermodynamics.

Heat, Temperature, Heat Transfer & Thermodynamics

States of Matter Solid Lowest energy/heat Molecules barely moving Definite, uniform shape Example: ice.

Heat. Internal Energy Energy of all molecules including –Random motion of individual molecules = 3/2 k T for ideal gas Vibrational energy of molecules.

Chapter 5 Temperature and Heat Another Kind of Energy.

Chapter 10 Heat Thermal Equilibrium Bring two objects into thermal contact. –They can exchange energy. When the flow of energy stops, the objects are.

Thermodynamics.

Changes of Phase List the four phases of matter in order of increasing internal energy.

Pre-AP Physics Unit 6: Thermodynamics. “Thermodynamics”  Is derived from Greek meaning “movement of heat.”

Thermodynamics. Heat Vs Temperature 4 Temperature is NOT heat! 4 Heat is energy (kinetic energy of atoms and molecules) 4 Temperature is the level of.

Chapter 6.  Temperature ◦ Is something hot or cold? ◦ Relative measure.

Thermal Physics (3) This abstract topic connects the atomic world to the observable world. For example, why do tires need to have air pumped in them as.

4.3 SPECIFIC LATENT HEAT.

Prof. Fred Remer University of North Dakota Phase Changes and Latent Heat Where’s the heat? Solid Liquid Gas.

Heat, Temperature, Heat Transfer, Thermal Expansion & Thermodynamics.

The Nature of Matter. Liquids The ability of gases and liquids to flow allows then to conform to the shape of their containers. Liquids are much more.

© 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their.

A Macroscopic Description of Matter

Determine the heat capacity (in calories/C°) of a lake containing two million gallons (approximately 8 million kilograms) of water at 15C°. Select.

IB Physics Topic 3 – Introduction to Thermo physics Mr. Jean.

Heat – Thermal Energy ISCI What is Heat? Place your finger on the handle of a ‘hot’ pan. Ouch! Heat is energy that is transferred from one ‘system’

Physical Science Mr. Moss RHS.  When 2 states are present at the same time, we describe each as a phase.  Here, we see 2 phases of water: ◦ Solid Phase.

Thermodynamics. Thermodynamics – The study of heat transformation. Temperature – A measure of the average kinetic energy of the particles in an object.average.

Energy and Phases.  Potential Energy - stored energy (stored in bonds, height)  Kinetic Energy - energy of motion, associated with heat.

Heat. What causes the temperatures of two objects placed in thermal contact to change? Something must move from the high temperature object to the low.

What happens to molecules as the temperature increases? Kinetic Energy Increases, they move faster What are on the axis of a phase change diagram? Temperature.

Chapter 17 Energy in Thermal Processes: First Law of Thermodynamics.

Herriman High Honors Physics Chapter 9 Temperature and Heat.

Thermodynamics.

Thermochemistry. Thermochemistry is the study of heat changes that occur during chemical reactions. Heat (q) - energy that is transferred from one object.

Thermal Force Unit 1.4

The First Law of Thermodynamics The Law of Conservation of Energy.

Energy Changes & Phase Changes. It takes energy to heat stuff up! For pure substance in single phase, can calculate how much using Q = mC  T For pure.

Phase Changes. Drill Convert 15 degrees Fahrenheit to Celsius Convert your answer to Kelvin How many states of matter exist? What are they?

Phase Changes.  A PHASE CHANGE is a reversible physical change that occurs when a substance changes from one state of matter to another  The temperature.

Temperature and Heat Temperature & Scales Thermometry Thermal Expansion Heat and Internal Energy Heat Transfer Heat and Temperature Change, Specific.

Phase Changes Slide Show #2. Skip #1 & #2 We’ll get to these later.

CH. 12 Thermal Energy Sec. 12.1: Temperature & Thermal Energy.

1 15 Temperature, Heat, Expansion Temperature & Heat Internal Energy & Specific Heat Homework: RQ: 1, 2, 7, 8, 9, 10, 15, 21, 24.

Chapter 9 Heat.

Lecture 23: Heat l Internal Energy l Heat l Specific Heat l Latent Heat l Phase Diagrams.

 Solid  Liquid  Gas  Plasma  Solid  Liquid  Gas  Plasma.

Temperature and Its Measurement When the physical properties are no longer changing, the objects are said to be in thermal equilibrium. Two or more objects.

HEATHEAT TEMPERATURE. WHAT YOU SHOULD KNOW A WARMER OBJECT CAN WARM A COOLER OBJECT BY CONTACT OR FROM A DISTANCE.

Vadodara institute of engineering Harshang shah( )

 Has fixed volume  Has fixed shape  Molecules are held in specific locations  by electrical forces  vibrate about equilibrium positions  Can be.

A Closer Look at Physical Properties Thermochemistry: States of Matter Thermochemistry:

First Law of Thermodynamics How is the CO 2 concentration in the atmosphere related to the melting of glaciers? How does sweating protect our bodies from.

Heat, Temperature, Heat Transfer, Thermal Expansion & Thermodynamics.

Kinetic Theory: all particles of matter are in constant motion. Particles of Matter: Smallest unit of pure substances, atoms or molecules.

Heat Changes in Temperature and Phase. Specific Heat Capacity Specific heat capacity – the quantity of energy needed to raise the temperature of 1 kg.

Phases of Matter, Bonding and Intermolecular Forces

Heat versus Temperature

CHANGES OF STATE.

Heat, Temperature, Heat Transfer, Thermal Expansion & Thermodynamics

Chapter 16 Temperature and Heat.

Heat, Temperature, & Thermodynamics

Heat, Temperature, Heat Transfer, Thermal Expansion & Thermodynamics

Presentation transcript:

18 Heat and the First Law of Thermodynamics Heat Capacity and Specific Heat Change of Phase and Latent Heat Joule’s Experiment and the First Law of Thermodynamics The Internal Energy of an Ideal Gas Work and the PV Diagram for a Gas Hk: 31, 37, 47, 51.

Heat & Internal Energy heat is energy that flows due to temperature differences. SI Unit: joule internal energy is the total energy of an object in its center of mass reference frame

Specific Heat Capacity The amount of heat needed to raise 1kg by 1°C c = Q/m  T SI Unit: J/kg·°C m = mass receiving (or emitting) heat  T = temperature change Q = mc  T /

Example: 300J of heat are added to 100grams of a substance. The temperature rises by 2.20 degrees C. The specific heat of the substance is: Example: Calorimetry

Other Heat & Energy Units:

Example Conversion A Gas Range is quoted (incorrectly) as “12,000 Btu”. The equivalent power for an Electric Range in watts is:

Solid/Liquid Transformation Melting Heat in KE breaks bonds Molecules move Liquid forms Freezing Heat out Molecules lose KE Settle in one place Solid forms

8 Energy in Phase Change Energy added: solid  liquid  gas energy released: gas  liquid  solid

Liquid/Gas Transformations Evaporation Highest KE molecules escape liquid from surface Evaporative cooling, e.g. sweat evaporates cooling your body Boiling Highest KE molecules form gas bubbles throughout Hot gas bubbles rise and escape at surface Liquid has passed heat out, e.g. simmering at constant temperature

Latent Heat Energy needed to melt or vaporize 1kg of a substance. Latent Heat, L = Q/m. Q = mL. Example: 2.5kg of ice at 0.0°C melts into 2.5kg of water at 0.0°C.

Joule’s Experiment confirmed the mechanical equivalent of heat.

1 st Law Thermodynamics

18-4 Internal Energy of Ideal Gas E-internal is proportional to the absolute temperature internal energy is in the kinetic energy of the molecules of the gas /

Work and the PV Diagram

Gas Processes Isobaric = constant pressure Isometric (Isochoric) = constant volume Isothermal = constant temperature Ex.

Summary: specific heat is material dependent. latent heats; objects change phase at constant temperature. calorimetry: science of heat measurements 1 st law of thermo. is energy conservation mechanical equivalent of heat Pressure x volume = work

Example: Human vs. Gasoline Engine Lance Armstrong: 460WV8: 200hp Power Ratio = 200hp/(460/746)hp = 332 times more Lance: (460W)(21,600) = 9.9 MJ = 2370 Cal Energy Consumption (6h = 21,600s): V8: (332 times more) = 3.3 GJ = 788,000 Cal

Which of the following is a unit of heat? 1.N/m 2.N/m 2 3.N·s 4.N·m

Heat is added to a system and the change in internal energy of the system is 1/3 of the heat added. Which of the following is true? 1.Work on system is + 2.Work on system is – 3.Work on system is 0

When not colliding, molecules of an ideal gas 1.Attract 2.Repel 3.Neither attract or repel

Molecules in an ideal gas 1.Never collide 2.Sometimes collide

18-5 Work and PV Diagrams

Work and PV [PV] = (N/m 2 )(m 3 )= joule = energy Work done by an expanding gas: Work done by gas during isothermal expansion:

Internal Energy of an Ideal Gas is proportional to temperature of gas internal energy is in the kinetic energy of molecules of the gas