Name: heat exchange in an insulated system
Uploaded: 2025-05-22T09:05:48.000Z
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K12 Standards

Tennessee Academic Standards

High School

Chemistry

Energy

CHEM1.PS3.2

Calorimetry

La calorimetria è la scienza che consiste nella misurazione del calore rilasciato e assorbito durante un processo fisico o chimico in condizioni ristrette.
Il principio della calorimetria implica che se due corpi sono isolati dall'ambiente circostante, il calore guadagnato dal corpo freddo è uguale alla perdita di calore dal corpo caldo, cioè la loro somma è uguale a zero.
Se 30 grammi di cubetti di ghiaccio a zero gradi Celsius vengono sciolti in 150 grammi di succo d'arancia a 40 gradi Celsius, quale sarebbe la temperatura finale del liquido dopo che tutto il ghiaccio si è sciolto? Il calore specifico del succo e del ghiaccio è di 4190 J/kg. K e 2100 J/kg. K, rispettivamente, e il calore di fusione del ghiaccio è 334x103 J/kg.
Innanzitutto, elenca le quantità note e sconosciute.
Ora applica il principio della calorimetria al succo e al ghiaccio.
Riorganizzare i termini per trovare un'espressione per la temperatura finale.
Sostituisci i valori per calcolare la temperatura finale del succo d'arancia, che è di 21,86 gradi Celsius.

<ol>
	<li>OpenStax. (2019). Fisica universitaria Vol. 2. [Versione web]. Estratto da <a href="https://openstax.org/details/books/university-physics-volume-2">https://openstax.org/details/books/university-physics-volume-2</a>; pagine 24-25.</li>
</ol>

calorimetria

Quando oggetti aventi diverse temperature sono messi in contatto tra loro ma isolati da qualcos'altro, essi raggiungono l'equilibrio termico. Un contenitore che previene il trasferimento di calore è chiamato calorimetro, e l'uso di un calorimetro per effettuare misurazioni è detto calorimetria. Generalmente, queste misurazioni comprendono il calore o la capacità di calore specifica. Il termine “problema di calorimetria” è usato per qualunque problema in cui gli oggetti specificati sono termicamente isolati dal loro ambiente. Un obiettivo importante nel risolvere i problemi di calorimetria è che durante il trasferimento di calore tra oggetti isolati dal loro ambiente, il calore ottenuto dall'oggetto più freddo dev'essere uguale al calore perso dall'oggetto più caldo a causa della conservazione dell'energia.

Per esempio, consideriamo una tazza d'acqua versata in una padella d'alluminio calda posta fuori dal fornello. Qui, la padella è posta su un sottopentola, e il trasferimento di calore all'aria viene trascurato nel breve tempo necessario a raggiungere l'equilibrio. Di conseguenza, questo è il problema del calorimetro, anche se non è specificato nessun contenitore isolante. Originalmente, la padella e l'acqua non erano in equilibrio termico. La padella è ad una temperatura maggiore dell'acqua. Il calore trasferito ripristina l'equilibrio termico una volta che l'acqua e la padella sono in contatto; si arresta una volta raggiunto l'equilibrio termico tra la padella e l'acqua. Il calore perso dalla padella è uguale al calore ottenuto dall'acqua, che è il principio di base della calorimetria.

Calorimetria

Quando oggetti a temperature diverse vengono messi in contatto tra loro ma isolati da tutto il resto, raggiungono l'equilibrio termico. Un...

Education

Didattica

JoVE Core

Physics

Fisica

Unit 1

Unità 1

Temperature and Heat

Temperatura e Calore

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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...

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Thermal Equilibrium and the Zeroth Law

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thermometers and temperature scales

How Thermometers Measure Heat

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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

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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

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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

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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

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conduction, convection and radiation: problem solving

conduction-convection-and-radiation-problem-solving

Heat Transfer Calculations with Conduction, Convection

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radiation: applications

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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

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Minnesota Academic Standards in Science

9-12

1.2.1 9C.4.2.1.2

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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

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Heat Flow and Specific Heat

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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

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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

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Differential Scanning Calorimetry

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Conservation of Energy

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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.)

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Thermochemical Equations

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Activation Energy

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Bond Energies and Bond Lengths

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Introduction to Chemical Reactions

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bond-dissociation-energy-and-activation-energy

Bond Dissociation Energy and Activation Energy

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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

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Conservation of Energy Approach to System Analysis

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First Law of Thermodynamics

Energy Conservation

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Conservation of Mechanical Energy

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Energy and Work

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Conservative Forces

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Non-conservative Forces

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Energy Diagrams - I

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Energy Diagrams - II

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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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