Name: how energy changes in chemical reactions
Uploaded: 2020-09-03T13:38:27.000Z
Duration: 2 min 27 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Chemistry

Energy

PS.Chm.7.2

Energy Basics

나트륨 금속은 물과 반응하여 수소가스를 만들지만 왜 염화나트륨은 그냥 용해되기만 할까요? 이것은 열화학'이라고 불리는 화학 물질과 에너지의 관계를 연구하여 설명할 수 있습니다. 모든 형태의 물질은 에너지와 연관되어 있으며 에너지는 열이나 수행한 일로 측정할 수 있습니다.

두 가지 주요 에너지 유형은 위치 및 운동 에너지입니다. 위치 에너지는 물체에 작용하는 위치상의 힘을 나타냅니다. 언덕 위에 있는 바위는 지구의 질량 중심에서 더 멀리 떨어져 있기 때문에 아래쪽에 있는 바위보다 더 많은 위치 에너지를 가지고 있습니다.

운동 에너지는 움직이는 물체가 가진 에너지입니다. 만약 바위를 언덕에서 내리밀면 바위는 위치 에너지를 잃지만 운동하기 때문에 운동 에너지를 얻습니다. 이런 관계는 물체를 구성하는 원자나 분자에도 적용됩니다.

정지해 있는 물체도 그의 성분 원자가 진동하기 때문에 여전히 운동 에너지를 가지고 있습니다. 이러한 형태의 운동에너지를 열에너지라고 합니다. 원자가 더 활발하게 움직이면 물체는 더 높은 운동 에너지를 가지며 결과적으로 더 높은 열 에너지를 가집니다.

이런 물체는 뜨거운 것으로 인식됩니다 분자도 화학 에너지라고 불리는 위치에너지를 가지고 있는데 이것은 전자와 핵의 상대적인 위치와 관련이 있습니다. 반응하는 동안 화학 에너지는 빛과 같은 다른 형태의 에너지로 변환되거나 또는 열의 형태로 방출됩니다. 변환되는 에너지의 양은 반응물의 분자 구조에 따라 달라집니다.

가스등에서 아세틸렌은 연소하여 빛으로 많은 양의 에너지를 방출하면서 이산화탄소와 물로 변환됩니다. 반면에 염산에 수산화나트륨을 첨가하면 적은 양의 에너지를 열 형태로 방출합니다. 에너지 변화에 대한 연구를 하기 위해, 관찰되는 과정을 포함하는 계'와 그 밖의 다른 모든 것을 포함하는 환경'으로 나눕니다.

계는 열린 계일 수 있습니다. 즉, 계와 환경 간에 에너지와 질량 모두를 교환할 수 있습니다. 계는 에너지만 교환되는 닫힌 계일 수도 있고 질량이나 에너지가 모두 교환되지 않는 고립 계일 수도 있습니다.

에너지의 기초

성냥에 불을 붙일 때 일어나는 것과 같은 화학 반응에는 물질뿐만 아니라 에너지의 변화도 포함됩니다.

화학적 변화와 이에 따른 에너지 변화는 일상생활의 중요한 부분입니다. 음식에 함유된 다량 영양소는 신체 기능을 유지하는 데 필요한 에너지를 제공하는 대사 반응을 겪습니다. 다양한 연료(휘발유, 천연가스, 석탄)를 연소하여 운송, 난방, 전기 생산에 필요한 에너지를 생산합니다. 산업 화학 반응에서는 원자재(예: 철, 알루미늄)를 생산하기 위해 엄청난 양의 에너지를 사용합니다. 그런 다음 에너지는 이러한 원자재를 자동차, 고층 건물, 교량과 같은 유용한 제품으로 제조하는 데 사용됩니다.

인간이 사용하는 에너지의 90% 이상이 원래 태양에서 나옵니다. 매일, 태양은 그날 필요한 전 세계 에너지 수요를 충족하는 데 필요한 양의 거의 10,000배에 달하는 에너지를 지구에 제공합니다. 들어오는 태양 에너지를 편리하고 오염되지 않은 반응이나 화학 공정에 사용할 수 있도록 변환하고 저장하는 방법을 찾는 것이 과제로 남아 있습니다. 식물과 많은 박테리아는 광합성을 통해 태양 에너지를 얻습니다. 인간은 나무, 석탄, 석유 또는 에탄올과 같은 기타 식물성 제품을 태울 때 식물에 저장된 에너지를 방출합니다. 이것은 또한 식물에서 직접 나오는 음식을 먹음으로써 몸에 연료를 공급하기 위해 이 에너지를 사용합니다.

열화학

화학적 및 물리적 변화 중에 흡수되거나 방출되는 열의 양과 관련된 중요한 과학 분야의 기본 아이디어를 열화학이라고 합니다. 이 개념은 거의 모든 과학 및 기술 분야에서 널리 사용됩니다. 식품 과학자들은 열화학을 사용하여 식품의 에너지 함량을 결정합니다. 생물학자들은 설탕이 이산화탄소와 물로 대사 연소되는 것과 같은 살아있는 유기체의 에너지학을 연구합니다. 석유, 가스, 운송 산업, 재생 가능 에너지 공급업체 및 기타 많은 기업은 상업적 및 개인적 필요에 맞게 에너지를 생산하는 더 나은 방법을 찾기 위해 노력하고 있습니다. 엔지니어들은 에너지 효율성을 향상시키고, 집을 난방 및 냉방하는 더 나은 방법을 찾고, 음식과 음료를 냉장하고, 다른 응용 분야 중에서도 컴퓨터와 전자 제품의 에너지 및 냉각 요구 사항을 충족시키기 위해 노력하고 있습니다. 열화학 원리를 이해하는 것은 화학자, 물리학자, 생물학자, 지질학자, 모든 유형의 엔지니어, 그리고 모든 종류의 과학을 연구하거나 수행하는 거의 모든 사람에게 필수적입니다.

에너지

에너지는 열을 공급하거나 일을 하는 능력으로 정의할 수 있습니다. 일(w)의 한 가지 유형은 반대되는 힘에 맞서 물질을 움직이게 하는 과정입니다. 예를 들어, 자전거 타이어에 공기를 주입할 때 이미 타이어에 들어 있는 공기의 반대 힘에 맞서 물질(펌프 안의 공기)이 이동합니다.

물질과 마찬가지로 에너지도 다양한 유형으로 제공됩니다. 한 체계는 에너지를 두 가지 유형으로 분류합니다. 위치 에너지(상대적 위치, 구성 또는 조건으로 인해 물체가 갖는 에너지)와 운동 에너지(물체가 운동으로 인해 소유하는 에너지)입니다.

폭포나 댐 꼭대기의 물은 그 위치 때문에 위치 에너지를 가지고 있습니다. 발전기를 통해 아래로 흐르면 수력 발전소에서 일을 하고 전기를 생산하는 데 사용할 수 있는 운동 에너지를 갖게 됩니다. 배터리에 들어 있는 화학 물질이 일을 할 수 있는 전기를 생산할 수 있기 때문에 배터리에는 위치 에너지가 있습니다.

이 문서는 에서 발췌되었습니다 <a href="https://openstax.org/books/chemistry-2e/pages/5-1-energy-basics">OpenStax Chemistry 2e, Section 5.1: Energy Basics</a>.

성냥에 불을 붙일 때 발생하는 것과 같은 화학 반응은 물질뿐만 아니라 에너지의 변화를 포함합니다.

화학적 변화와 그에 수반되는 ...

Education

교육

JoVE Core

화학

하나

Thermochemistry

열화학

KEY TERMS AND CONCEPTS

주요 용어 및 개념

how energy changes in chemical reactions

Chemical reactions change matter and energy at the same time. A match lighting is a simple example. These energy changes are part of everyday life and appear in food, fuels, and industry.

Food provides energy through metabolic reactions. The macronutrients in food break down and help keep the body functioning. Fuels such as gasoline, natural gas, and coal are burned to produce energy for transportation, heating, and electricity generation.

Industrial chemical reactions also use large amounts of energy. That energy helps make raw materials like iron and aluminum. More energy is then needed to turn those materials into products such as cars, skyscrapers, and bridges.

Most energy used by humans comes from the sun. Every day, the sun sends Earth almost 10,000 times more energy than the world needs for that day. The challenge is to capture and store solar energy so it can drive chemical processes that are useful, convenient, and nonpolluting.

Plants and many bacteria capture solar energy through photosynthesis. Humans release stored energy by burning wood, coal, petroleum, or plant products such as ethanol. They also use this energy directly when they eat food that comes from plants.

Thermochemistry is the study of heat absorbed or released during chemical and physical changes. It is used to measure the energy content of foods and to study the energetics of living organisms, such as the breakdown of sugar into carbon dioxide and water. It also supports work in the oil, gas, transportation, and renewable energy industries, as well as in engineering.

Energy is the capacity to supply heat or do work. Work means causing matter to move against an opposing force, such as when air is pushed into a bicycle tire. Energy can be described as potential energy, which depends on position, composition, or condition, and kinetic energy, which depends on motion.

A waterfall or dam stores potential energy because of its position. When the water flows downward through generators, it has kinetic energy that can do work and produce electricity in a hydroelectric plant. A battery also stores potential energy because the chemicals inside it can produce electricity when needed.

How Energy Changes in Chemical Reactions

energy basics

Chemical reactions change matter and energy at the same time. A match lighting is a simple example. These energy changes are part of everyday life and appear in food, fuels, and industry. Food provides energy through metabolic reactions. The macronutrients in food break down and help keep the body functioning. Fuels such as gasoline, natural gas, and coal are burned to produce energy for transportation, heating, and electricity generation. Industrial chemical reactions also use large amounts...

first law of thermodynamics

Energy Conservation and Internal Energy

Energy conservation describes how energy changes form during chemical and physical changes. Energy can be converted from one form into another, but the energy present before a change still exists in some form after the change is complete. This is the law of conservation of energy. It says energy can neither be created nor destroyed. The law of conservation of matter also applies during chemical change. In most chemical reactions, the total amount of matter does not show a detectable change.

internal energy

Internal Energy, Heat, and Work

Internal energy is the total of all possible kinds of energy in a substance. It is often written as U, and sometimes as E. For a system that changes energy, the important value is the change in internal energy, or ΔU. ΔU is the difference between the final internal energy and the initial internal energy. The exact values of U final and U initial are usually not known, but the first law of thermodynamics only requires ΔU. A positive ΔU means the system gained energy from the surroundings. A...

quantifying heat

Heat Transfer and Specific Heat

Heat transfer and specific heat explain how thermal energy moves and how materials respond to it. Thermal energy is the kinetic energy linked to the random motion of atoms and molecules. Temperature is a measure of how hot or cold a substance is, and it depends on how much thermal energy those particles have. When atoms and molecules move or vibrate faster, their average kinetic energy is higher. That means the object has more thermal energy and a higher temperature. When they move more...

quantifying work

Pressure-Volume Work in Chemistry

Pressure-volume work shows how gas volume changes can transfer energy in chemistry. As a system changes, its internal energy may change too. Energy can move between the system and the surroundings through heat and work. Internal energy, heat, and work are related by an energy equation. Heat depends on a measured temperature change. Work depends on a measured change in volume called pressure-volume work. Work can be defined as a force acting through a distance. Pressure-volume work, also...

enthalpy

Enthalpy and Heat at Constant Pressure

Enthalpy describes heat changes in chemical and physical processes. Chemists use the symbol H for enthalpy. It is defined as a system’s internal energy, E, plus the product of pressure, P, and volume, V. Enthalpy is a state function, so only changes in enthalpy can be measured, not the enthalpy of a substance by itself. For many reactions, the pressure stays constant. Under those conditions, the enthalpy change, ΔH, can be written in a way that includes pressure-volume work. The term PΔV...

thermochemical equations

Heat Changes in Chemical Equations

Heat changes in chemical equations show how much energy a reaction releases or absorbs. At constant pressure, the enthalpy of reaction, or ΔHrxn, is equal to the heat exchanged with the surroundings, qp. Because this value depends on how much reactant takes part, it is an extensive property. The size and sign of ΔHrxn also depend on the reaction itself and on the physical states of the substances involved. An exothermic reaction has a negative ΔHrxn value, while an endothermic reaction has a...

constant pressure calorimetry

Coffee Cup Calorimeter Heat Changes

Coffee cup calorimetry measures heat changes in reactions and physical changes using an insulated calorimeter. The calorimeter is calibrated and designed to limit heat exchange with the outside environment. That makes it possible to measure the heat taken in or released by a substance more accurately, including the energy content of foods. In calorimetry, the system is the substance or substances undergoing change. The surroundings are everything else inside the calorimeter, including the...

constant volume calorimetry

Bomb Calorimeter Heat Measurement

Bomb calorimetry measures the heat released by reactions that produce a lot of energy, especially combustion reactions. A coffee cup calorimeter works at constant pressure and is useful for reactions in solution. A bomb calorimeter works at constant volume and is used for reactions that make large amounts of heat and gaseous products. The word "bomb" refers to the strong, explosive force some reactions can have. In a bomb calorimeter, the volume does not change, so 94V = 0. That means the...

hess's law

Calculating Reaction Heat with Hess's Law

Calculating reaction heat with Hess's law lets chemists find enthalpy changes without measuring every reaction directly. Some reactions are hard or impossible to test in the lab. Even when a reaction can be measured, it is often easier to calculate the heat change from other known enthalpy values. Hess's law says that if a process can be written as the sum of several stepwise processes, the enthalpy change for the total process equals the sum of the enthalpy changes for the steps. This works...

standard enthalpy of formation

Using Standard Enthalpy Values in Chemistry

Enthalpy changes are often listed for reactions that start and end under the same conditions. Chemists use a standard state as a reference set of conditions for comparing properties. In IUPAC terms, the standard state means 1 bar of pressure and 1 M solutions, but it does not set a temperature. Many thermochemical tables still use 1 atm as the reference pressure. Because the difference between 1 bar and 1 atm is very small, enthalpy change usually stays almost the same. A superscripted o in...

enthalpies of reaction

Calculating reaction heat with Hess's law uses standard enthalpies of formation to find the enthalpy change of a reaction. When the formation values for the reactants and products are known, the overall reaction can be broken into simpler stepwise reactions. This approach helps show how the heat change for the full reaction is built from smaller parts. First, the reactants are thought of as being decomposed into their component elements. The enthalpy change for this step is proportional to the...

key terms and concepts

Explore how chemical reactions change energy in food, fuels, photosynthesis, thermochemistry, and batteries. Built for high school science learners.

How Energy Changes in Chemical Reactions | JoVE K12

chemistry

JoVE Core 화학은 간결하고 이해하기 쉬운 애니메이션을 통해 일반 화학 개념을 설명합니다. 또한, 과학자가 직접 고전실험과 연구실험을 진행하는 실사 영상을 제공합니다.

Matter and its Interactions

PS.Chm.4.1

Earth and Environmental Science

Earth's Systems

ESS.EES.3.2

Physical Science

PS.PSc.7.1

Pennsylvania State Academic Standards

3.2.9-12.O

3.2.9-12.P

3.2.9-12.Q

3.2.9-12.R

Louisiana Student Standards for Science

High School

Matter And Its Interactions

HS-PS1-4

HS-PS1-5

HS-PS3-2

HS-PS3-3

HS-PS3-4

Physics

HS-PS3-1

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Classification of matter

Energy And Waves

Thermal energy

Interactions Of Matter

Chemical reactions

Physical Geology

Earth's Resources

Energy resources

Tennessee Academic Standards

CHEM1.PS3.3

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.a

Earth Science

ES.6

ES.6.d

Minnesota Academic Standards in Science

3.1.1 9C.2.2.1.1

Texas Essential Knowledge and Skills

CHEM.13

CHEM.13.A

CHEM.13.C

Alabama Course of Study Science

9-12.PS.1.1

Earth and Space Science

Earth's Place in the Universe

9-12.ESS.1.1

9-12.ESS.1.1.a

Next Generation Science Standards

Life Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-7

Florida Department of Education

SC.912.E.6

SC.912.E.6.6

SC.912.P.10

SC.912.P.10.1

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

Matter and Its Interactions

C-PS1-4

C-PS1-5

C-PS3-4

P-PS3-1

P-PS3-2

P-PS3-3

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Energy

HS-PS3-1.

Georgia Standards of Excellence

SPS7.

Types of Energy

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

comparing-intermolecular-forces-melting-point-boiling-point

Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility

Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

surface-tension-capillary-action-and-viscosity

Surface Tension, Capillary Action, and Viscosity

Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded ...

States of Matter and Phase Changes

The internal energy of a substance&#8212;the total kinetic energy of all its molecules and the potential energy of their associated forces&#8212;depends ...

Phase Transitions

Whether solid, liquid, or gas, a substance&#39;s state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the ...

phase-transitions-vaporization-and-condensation

Phase Transitions: Vaporization and Condensation

The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize ...

Vapor Pressure

When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules move randomly about, they will occasionally ...

Clausius-Clapeyron Equation

The equilibrium between a liquid and its vapor depends on the temperature of the system; a rise in temperature causes a corresponding rise in the vapor ...

Phase Transitions: Melting and Freezing

Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy ...

phase-transitions-sublimation-and-deposition

Phase Transitions: Sublimation and Deposition

Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and ...

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 ...

Phase Diagrams

A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. ...

Use models to explain how changes in energy affect the arrangement and movement of the particles in solids, liquids, and gases, as well as the relative strengths of their intermolecular forces.

PS.Chm.7.1

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 ...

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 ...

Internal Energy

The total of all possible kinds of energy present in a substance is called the internal energy (U), sometimes symbolized as E. Suppose a system with ...

Quantifying Heat

Thermal Energy&#160;

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

Quantifying Work

As a system undergoes a change, its internal energy can change, and energy can be transferred from the system to the surroundings, or from the ...

Enthalpy

Chemists ordinarily use a property known as enthalpy (H) to describe the thermodynamics of chemical and physical processes. Enthalpy is defined as the sum ...

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 ...

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 ...

Use mathematics and computational thinking to execute simple calorimetric calculations based on the Law of Conservation of Energy.

Understand the relationship among pressure, temperature, volume, and phase.

How Energy Changes in Chemical Reactions

Description

Transcript

More videos by Standards