Name: heat exchange in an insulated system
Uploaded: 2025-05-22T09:05:48.000Z
Duration: 1 min 19 s
Channel: JoVE

K12 Standards

Tennessee Academic Standards

High School

Chemistry

Energy

CHEM1.PS3.2

Calorimetry

קלורימטריה היא המדע של מדידת החום המשתחרר ונספג במהלך תהליך פיזי או כימי בתנאים מוגבלים.
עקרון הקלורימטריה מרמז שאם שני גופים מבודדים מהסביבה, החום המתקבל על ידי הגוף הקר שווה לאיבוד החום על ידי הגוף החם, כלומר, הסכום שלהם שווה לאפס.
אם 30 גרם קוביות קרח באפס מעלות צלזיוס מומסים ב-150 גרם מיץ תפוזים ב-40 מעלות צלזיוס, מה תהיה הטמפרטורה הסופית של הנוזל אחרי שכל הקרח נמס? החום הסגולי של מיץ וקרח הוא 4190 J / kg. K ו- 2100 J/kg. K, בהתאמה, וחום היתוך הקרח הוא 334x103 J/kg.
ראשית, רשום את הכמויות הידועות והלא ידועות.
עכשיו ליישם את העיקרון של קלורימטריה מיץ וקרח.
סדר מחדש את המונחים כדי למצוא ביטוי עבור הטמפרטורה הסופית.
החלף את הערכים כדי לחשב את הטמפרטורה הסופית של מיץ תפוזים, שהוא 21.86 מעלות צלזיוס.

<ol>
	<li>OpenStax. (2019). פיזיקה אוניברסיטאית כרך 2. [גרסת אינטרנט]. מקור: <a href="https://openstax.org/details/books/university-physics-volume-2">https://openstax.org/details/books/university-physics-volume-2</a>; עמ' 24-25.</li>
</ol>

קלורימטריה

<div style="direction:rtl">כאשר עצמים בטמפרטורות שונות מונחים במגע זה עם זה אך מבודדים מכל השאר, הם מגיעים לשיווי משקל תרמי. מיכל שמונע העברת חום פנימה או החוצה נקרא קלורימטר, והשימוש בקלורימטר לביצוע מדידות נקרא קלורימטריה. בדרך כלל, מדידות אלה כרוכות בחום או בקיבולת חום ספציפית. המונח "בעיית קלורימטריה" משמש לכל בעיה שבה האובייקטים שצוינו מבודדים תרמית מסביבתם. מטרה חשובה בפתרון בעיות קלורימטריה היא שבמהלך העברת חום בין עצמים המבודדים מסביבתם, החום שנצבר על ידי החפץ הקר יותר חייב להיות שווה לחום שאבד על ידי החפץ החם יותר עקב שימור האנרגיה. לדוגמה, חשבו על כוס מים שנשפכה למחבת אלומיניום חמה שהונחה מהכיריים. כאן מניחים את המחבת על כרית מבודדת, והעברת החום לאוויר מוזנחת בזמן הקצר הדרוש כדי להגיע לשיווי משקל. כתוצאה מכך, מדובר בבעיית קלורימטריה, למרות שלא צוין מיכל מבודד. במקור, המחבת והמים לא היו בשיווי משקל תרמי. המחבת בטמפרטורה גבוהה יותר מהמים. העברת חום מחזירה את שיווי המשקל התרמי ברגע שהמים והמחבת נמצאים במגע; הוא מפסיק ברגע שהשיווי משקל תרמי בין המחבת למים מושג. החום שמאבד המחבת שווה לחום שצבר המים, שהוא העיקרון הבסיסי של הקלורימטריה.</div>

כאשר עצמים בטמפרטורות שונות נמצאים במגע זה עם זה אך מבודדים מכל דבר אחר, הם מגיעים לשיווי משקל תרמי. A ...

Education

JoVE Core

Physics

פיזיקה

Unit 1

יחידה 1

Temperature and Heat

טמפרטורה וחום

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

heat exchange in an insulated system

Calorimetry studies heat exchange in an insulated system. A calorimeter is a container that prevents heat transfer in or out. Scientists use calorimetry to measure heat and specific heat capacity.

A calorimetry problem is any situation where the objects are thermally isolated from their surroundings. The key idea comes from conservation of energy. During heat transfer, the heat gained by the colder object must equal the heat lost by the hotter object.

A simple example is water poured into a hot aluminum pan after it is taken off the stove. The pan sits on an insulated pad, and heat transfer to the air is neglected over the short time needed to reach equilibrium. Even without a special container, this setup still counts as a calorimetry problem.

At the start, the pan and the water are not in thermal equilibrium. The pan is hotter than the water. Heat flows until both reach the same temperature, and then the transfer stops. At that point, the heat lost by the pan equals the heat gained by the water.

Heat Exchange in an Insulated System

temperature and thermal equilibrium

Heat, Temperature, and Everyday Energy

Heat and temperature are key ideas in thermodynamics and in everyday life. People often connect temperature with hot and cold, but science gives it a more precise meaning. Temperature is the quantity measured with a thermometer. It is also linked to the average translational kinetic energy of particles. Heat is different from temperature. Heat is energy that moves from one place or material to another because there is a difference in temperature. That difference in temperature keeps heat...

zeroth law of thermodynamics

Thermal Equilibrium and the Zeroth Law

The zeroth law of thermodynamics explains thermal equilibrium between objects. If object A is in equilibrium with object B, and object B is in equilibrium with object C, then object A is also in equilibrium with object C. This transitive relationship is the key idea behind the law. A simple example uses metal blocks and a metal plate at room temperature. A cold metal block and a hot metal block are both placed on the plate. Over time, the cold block and the plate reach thermal equilibrium, and...

thermometers and temperature scales

How Thermometers Measure Heat

Thermometers measure temperature by using physical properties that change in a predictable way. One common example is volume. For most substances, volume increases as temperature rises. That idea is used in alcohol thermometers and in the original mercury thermometers. Other thermometer designs use different temperature-sensitive properties. Some measure electrical resistance, color, or the emission of infrared radiation. The alcohol thermometer is a common example. It contains red-dyed...

gas thermometers and the kelvin scale

Kelvin Temperature and Gas Thermometer Standards

Kelvin temperature is the absolute scale used in science, and it starts at absolute zero. That zero point matches the lowest possible temperature, where molecular motion reaches zero or the minimum allowed by quantum mechanics. Scientists use this scale because some physical quantities, such as the volume of an ideal gas, depend directly on absolute temperature. The Kelvin scale is part of the SI system of units, so its definition is more precise than simply using water’s freezing and boiling...

thermal expansion

Thermal Expansion in Air, Water, and Solids

Thermal expansion is the change in size or volume of a material as its temperature changes. A common example is the alcohol inside a thermometer. As the temperature rises, the alcohol expands and shows the change. Heated air also expands. It becomes less dense than the cooler air around it, so the surrounding air pushes it upward. This is why steam and smoke rise and why hot air balloons float. The same effect happens in liquids and gases, and it helps move heat upward in homes, oceans, and...

thermal stress

How Temperature Changes Create Stress

Thermal stress is the stress that builds up when an object changes temperature but cannot expand or contract freely. If the object would expand without restraint, the stress is compressive. If it would contract, the stress is tensile. This stress from heating or cooling can become large enough to cause damage. Engineers often reduce it by designing parts so they can move as temperature changes. Highway blocks, for example, are separated by gaps so thermal stress does not build up. When gaps...

thermal expansion and thermal stress: problem solving

thermal-expansion-and-thermal-stress-problem-solving

Golden Gate Bridge Thermal Expansion

Thermal expansion and thermal stress are shown through the Golden Gate Bridge. The bridge faces temperatures from -15 °C to 40 °C. At its coldest, the main span is 1275 m long. Assuming the bridge is made entirely of steel, the example asks for the change in its length across this temperature range. To solve the problem, the known values must be identified first. The initial length is 1275 m. The coefficient of linear expansion for steel is 12 x 10 -6 /°C, and the change in temperature is 55...

heat flow and specific heat

Heat Units and Specific Heat

Heat is energy transferred because of a temperature difference, and it can change an object’s temperature. Since heat is energy, its SI unit is the joule (J). Heat transfer is the movement of energy from one place or material to another, and it plays a role in home heating, cooking, and many industrial processes. Two common units for heat are the calorie and the kilocalorie. A calorie (cal) is the energy needed to change the temperature of 1 g of water by 1 °C, specifically between 14.5 °C and...

phase changes

Heat and Phase Change Energy

Heat and phase change energy explain why substances melt, freeze, boil, and condense. A solid turns into a liquid during melting, also called fusion. The reverse process is freezing. A liquid turns into a gas during evaporation. The reverse process is condensation. Each substance changes phase at specific temperatures. The melting point is the temperature where a substance melts or freezes. The boiling point is the temperature where a substance boils or condenses. These temperatures depend on...

calorimetry

Calorimetry studies heat exchange in an insulated system. A calorimeter is a container that prevents heat transfer in or out. Scientists use calorimetry to measure heat and specific heat capacity. A calorimetry problem is any situation where the objects are thermally isolated from their surroundings. The key idea comes from conservation of energy. During heat transfer, the heat gained by the colder object must equal the heat lost by the hotter object. A simple example is water poured into a...

mechanisms of heat transfer i

Three Ways Heat Moves Between Objects

Heat transfer happens when there is a temperature difference. It can move fast, like through a cooking pan, or slowly, like through the walls of a picnic ice box. Heat transfer appears in many everyday situations, so it is hard to find a place where it does not occur. There are only three ways heat is transferred: conduction, convection, and radiation. A fireplace shows all three at once. Radiation carries most of the heat into the room. Conduction also moves heat into the room, but much more...

mechanisms of heat transfer ii

Convection and Radiation in Heat Transfer

Convection and radiation are two major ways heat moves. In convection, thermal energy is carried by the large-scale flow of matter. Warm air and water rise because they are less dense, so ocean currents and large-scale atmospheric circulation move heat from the tropics toward the poles and move cold air from the poles toward the tropics. Earth’s rotation changes these moving air currents. It interacts with the flow and helps produce the eastward movement of air in the temperate zones.

conduction, convection and radiation: problem solving

conduction-convection-and-radiation-problem-solving

Heat Transfer Calculations with Conduction, Convection

Heat transfer calculations with conduction and convection use the temperature difference to find the rate of heat flow. Radiation can also be part of the process. The main idea is that heat moves only because one area is hotter than another, and a larger temperature difference leads to faster transfer. To solve a heat transfer problem, first identify the type of transfer involved. It may be conduction, convection, radiation, or a combination of all three. Next, write down the unknown...

radiation: applications

Earth’s Energy Balance and Greenhouse Effect

Earth’s energy balance and the greenhouse effect help explain its average temperature. Earth is in radiative contact with both the Sun and dark space. It receives almost all of its energy from solar radiation, and it reflects some of that energy back into outer space. Dark space is very cold, about 3 K, so Earth also radiates energy into it. Heat can move quickly from soil and grasses, and frost can form on clear summer evenings, even in warm latitudes. In a first approximation, Earth’s...

absorption of radiation

Radiation Heat Transfer and Thermographs

Radiation heat transfer depends on temperature, surface area, and emissivity. The Stefan-Boltzmann law describes the rate of heat transfer by emitted radiation. In this law, σ is the Stefan-Boltzmann constant, A is the object’s surface area, and T is its temperature in kelvins. The fourth-power dependence on absolute temperature makes radiation highly sensitive to small temperature changes. Even a slight rise in temperature can change the emitted heat a lot. That sensitivity is why radiation...

key terms and concepts

Explore calorimetry through thermal equilibrium, insulated systems, and heat transfer. See how a hot pan and cooler water reach the same temperature.

Heat Exchange in an Insulated System | JoVE K12

physics

JoVE Core Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

Minnesota Academic Standards in Science

9-12

1.2.1 9C.4.2.1.2

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

Physical Science

HS-PS3-4

Arizona Science Standards

HS+Phy.P4

HS+Phy.P4U1.6

Quantifying Heat

Thermal Energy&#160;

Microscopically, thermal energy is the kinetic energy associated with the random motion of atoms and molecules. Temperature is a ...

Temperature and Thermal Equilibrium

Heat and temperature are essential concepts for everyone every day. The study of heat and temperature is part of an area of physics known as ...

Types of Kinetic Energy

The amount of kinetic energy of an object depends on its mass and speed. Consider two balls of different masses rolling down an inclined plane at the same ...

Heat Flow and Specific Heat

Heat is a type of energy transfer that is caused by a temperature difference, and it can change the temperature of an object. Since heat is a form of ...

kinetic-molecular-theory-molecular-velocities-temperature-kinetic

Kinetic Molecular Theory: Molecular Velocities, Temperature, and Kinetic Energy

The kinetic molecular theory qualitatively explains the behaviors described by the various gas laws. The postulates of this theory may be applied in a ...

Constant Pressure Calorimetry

Calorimetry is a technique used to measure the amount of heat involved in a chemical or physical process or to measure the heat transferred to or from a ...

Contrast the concepts of temperature and heat flow in macroscopic and microscopic terms. Understand that thermal energy is a form of energy and temperature is a measure of average kinetic energy of a particle. EXPLANATION: Students have been exposed to the types of energy (potential, kinetic, thermal, and chemical) and energy transfer (working, heating, and radiating) in the sixth grade. At that time, students classified energy types in systems and transformations. The focus in Chemistry 1 should be on understanding that measuring the temperature of a system is a way to quantify the thermal energy (average kinetic energy) of the particles in that system. Heating is a mechanism that transfers energy to or from a system. Students should also explore absolute vs relative scales of temperature mechanisms. Students should recognize that energy will always flow from objects with greater thermal energy to areas with lesser thermal energy, but rates of energy flow are a property of the materials being heated. The degree to which the temperature changes as an object is also a physical property of a material. Activities may include collecting or analyzing pressure vs temperature data, then considering why a graph of collected data does not pass through the origin. (Heat capacity and conductivity will only be assessed qualitatively.)

CHEM1.PS3.1

Heating and Cooling Curves

When a substance&#8212;isolated from its environment&#8212;is subjected to heat changes, corresponding changes in temperature and phase of the substance ...

When objects at different temperatures are placed in contact with each other but isolated from everything else, they attain thermal equilibrium. A ...

Heat Exchanger Analysis

Source: Alexander S Rattner and Christopher J Greer; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, ...

Differential Scanning Calorimetry

Source: Danielle N. Beatty and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT
Differential ...

Constant Volume Calorimetry

Calorimeters are useful to determine the heat released or absorbed by a chemical reaction. Coffee cup calorimeters are designed to operate at constant ...

Conservation of Energy

The terms &#39;conserved quantity&#39;&#160;and &#39;conservation law&#39;&#160;have specific scientific meanings in physics, which differ from the ...

Draw and interpret heating and cooling curves and phase diagrams. Analyze the energy changes involved in calorimetry by using the law of conservation of energy quantitatively (use of $q=mc\Delta T)$ and qualitatively. EXPLANATION: This is one of two standards where students are to investigate changes in a specific types of energy: In this case, thermal energy and phase energy. Starting as early as kindergarten, students are introduced to solid and liquid phases of matter. By third grade, students are considering the particulate nature of matter to discuss physical properties of the different phases. In fifth grade, students discuss phase changes from the perspective of the arrangement of particles. Chemistry 1 is the first time that students make a connection between phase changes and energy changes. Students commonly struggle with the idea that substances can be heated, but that heating does not always result in a change in temperature. Models of phase energies associated with the arrangement of particles aid in dispelling these misconceptions. Comparisons should identify similarities in energies in solids and liquids as compared to vastly different energy in gases. Discussions of heat of fusion/vaporization and calculations to enrich these discussions are appropriate. Finally, students should be able to quantify relationships in which heating creates a change in the thermal energy of a sample. Activities may include determining energy released when an object is burned to change the temperature of a substance in a closed system. (Note that this standard is limited to calculations of energy associated with changes in thermal energy, and not energies associated with phase transformations.)

Energy Transfer in Chemical Reactions

Chemical reactions require sufficient energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ...

energy-diagrams-transition-states-and-intermediates

Energy Diagrams, Transition States, and Intermediates

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Energy Basics

Chemical reactions, such as those that occur when you light a match, involve changes in energy as well as matter.

Chemical changes and their accompanying ...

endergonic-and-exergonic-reactions-in-the-cell

Endergonic and Exergonic Reactions in the Cell

If energy releases during a chemical reaction, then the resulting value&#160;will be a negative number. In other words, reactions that release energy have ...

Thermochemical Equations

For a chemical reaction (the system) carried out at constant pressure &ndash; with the only work done caused by expansion or contraction &ndash; the ...

Activation Energy

Activation energy is the minimum amount of energy necessary for a chemical reaction to move forward. The higher the activation energy, the slower the rate ...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

Introduction to Chemical Reactions

All chemical reactions begin with a reactant, the general term for one or more substances entering the reaction. Sodium and chloride ions, for example, ...

bond-dissociation-energy-and-activation-energy

Bond Dissociation Energy and Activation Energy

Bond energy is the energy required to break a bond homolytically. These values are usually expressed in units of kcal/mol or kJ/mol and are referred to as ...

Distinguish between endothermic and exothermic reaction by constructing potential energy diagrams and explain the differences between the two using chemical terms (e.g. activation energy). Recognize when energy is absorbed or given off depending on the bonds formed and bonds broken. EXPLANATION: This is one of two standards where students are to investigate changes in a specific type of energy: In this case, chemical energy. Students should recognize that the formation of bonds releases energy, while the breaking of bonds is endothermic. Synthesis reactions to form metal oxides can provide observations if carried out taking proper precautions. Clear changes to masses and physical properties provide evidence of a reaction. (Specific discussions of enthalpy of formation are beyond the scope of this standard, but the topic may be useful for enrichment discussions about reactions where bonds are both broken and formed.)

CHEM1.PS3.3

Conservation of Energy: Application

When solving problems using the energy conservation law, the object (system) to be studied should first be identified. Often, in applications of energy ...

conservation-of-energy-approach-to-system-analysis

Conservation of Energy Approach to System Analysis

Source: Ricardo Mejia-Alvarez and Hussam Hikmat Jabbar, Department of Mechanical Engineering, Michigan State University, East Lansing, MI
The purpose of ...

What is Energy?

The universe is composed of matter in different forms, and all forms of matter contain energy. &#xA0;The different forms of energy on Earth originate from ...

First Law of Thermodynamics

Energy Conservation

Energy can be converted from one form into another, but all of the energy present before a change occurs always exists in some form ...

Conservation of Mechanical Energy

The mechanical energy E of a system is the sum of its potential energy U and the kinetic energy K of the objects within it. What happens to this ...

/files/media/science-education/science-education-thumbs/14702.jpg

Energy and Work

Source: Ketron Mitchell-Wynne, PhD,&#160;Asantha Cooray, PhD, Department of Physics &#38; Astronomy, School of Physical Sciences, University of ...

Conservative Forces

According to the law of conservation of energy, any transition between kinetic and potential energy conserves the total energy of the system. Hence, the ...

Non-conservative Forces

Non-conservative forces are dissipative forces such as friction or air resistance. These forces take energy away from a system as it progresses. Unlike ...

Energy Diagrams - I

The dynamics of a mechanical system can be easily understood by interpreting a potential energy diagram. Since energy is a scalar quantity, the ...

Energy Diagrams - II

Energy diagrams are important to understand the dynamics of a system. The topology of an energy diagram helps illustrate the equilibrium points of the ...

Analyze energy changes to explain and defend the law of conservation of energy. EXPLANATION: Standards PS3.2 and PS3.3 identify the energy types most commonly associated with chemical reactions and build on sixth grade discussions of energy storage and transfer types. In Chemistry 1, students will synthesize an understanding of law of conservation of energy by being able to distinguish system from surroundings, and recognizing that tracking energy requires both the system and surrounding energies to be considered. Students can consider interactions such as a beverage warming/cooling, a refrigerator cooling food, the function of Freon in cooling systems, or a car's cooling system as examples where multiple systems interact.

CHEM1.PS3.4

Heat Exchange in an Insulated System

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