Name: matter: elements, compounds, and mixtures
Uploaded: 2020-09-03T13:38:25.000Z
Duration: 3 min 35 s
Channel: JoVE

K12 Standards

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

North Carolina K-12 Science Standard Course of Study

9-12

Chemistry

Energy

PS.Chm.7.1

Classifying Matter by Composition

物質は原子 つまり物質の 最小の基本単位である原子と 2つ以上の原子が結合してできた 分子からできています その組成に基づいて 物質は純粋な物質と混合物の 2つのグループに 分類することができます 定義によれば 物質は1つの成分のみで構成され 全体的に均一な組成を持つ場合 純粋であると言われます 例えば 水素を考えてみます 水素は水素原子だけで 構成されています 同様に 水も 水分子のみで構成されています これらの組成は 試料ごとに 異なることはありません 純粋な物質は 分解できるかどうかによって 元素と化合物の2つのタイプに 分類できます 元素とは 化学的な方法で 単純な物質に 分解できない 純粋な物質のことです 例えば 水素は元素です 逆に化合物は 化学的な手段によって 構成要素に 分離可能な物質です 水も純粋な物質ですが 化学的に水素と酸素に 分解することができます 地球上では ほとんどの元素が 他の元素と容易に結合するため 純粋な元素よりも 化合物の方が一般的です 例えば 黒板に書くために 使用されるチョークは カルシウムと炭素 酸素でできています 砂糖は炭素と水素 酸素で作られています 一方混合物は 純粋な物質とは異なり 1つ以上の成分でできています また その割合も サンプルによって異なります 例えば レモネードは 3つの成分の混合物です レモン汁と砂糖と水です そしてそれらの比率は 自由に変化させることができます 混合物自体は それらの中の物質が 均一と不均一かに応じて 2つのタイプに分類できます 均一な混合物は 均一な組成を示し 全体を通して 視覚的に同じように見えます これはしばしば 溶液と呼ばれています 例えば スプーン一杯の塩を 水に溶かした場合 その混合物のすべての滴が 同じ組成を持っているので 均一な混合物が得られます 同様に レモネードも 均一な混合物です 不均一な混合物では 成分が一様に 分布していないため 組成はポイントごとに異なります 例えば砂と砂鉄が 混合された場合 この混合物の異なる部分には 異なる量の砂鉄と砂が含まれる 可能性が高くなります 均一であろうと不均一であろうと どのような混合物であっても 構成要素の同一性を変えずに 物理的手段によって 純粋な構成要素に 分離することができます 例えば 塩水中の塩は 混合物を加熱して乾燥させて 水溶液から 回収することができます 同様に 砂鉄は 磁石を使用して 砂から分離することができます

組成による物質の分類

<h4>物質：純粋な物質と混合物 </h4>
 
 組成によって、物質は純粋な物質と混合物という 2 つの大きなカテゴリーに分類されます。  
 
 純粋な物質とは、均一な性質を持ち一定の組成を持つ物質の一形態です。 例えば、スクロース試料は、どれから分離されたかに関係なく、融点、色、甘さなど、同じ組成と同じ物性を持ちます。  
 
 混合物は2種類以上の物質からなり、様々な質量を示す場合があり、蒸発といった物理的な変化によってそれらを分けることができます 。 混合物内の構成要素は、それぞれ固有な性質を保っています。 
 
 <h4>純粋な物質：元素および化合物 </h4>
 
 純粋な物質は、元素と化合物という 2 つのクラスに分けることができます。 化学物質の変化によって単純な物質に分解できない純粋な物質を元素と呼びます。 鉄、銀、金、アルミニウム、硫黄、 酸素と銅は元素です。 
 
 化学物質の変化によって分解できる純粋な物質を化合物と呼びます。 このような分解により、元素または他の化合物、あるいはその両方を生成する場合があります。 オレンジ色の結晶性固体である酸化水銀（ II ）は、熱によって水銀と酸素の元素に分解されます。 空気がない状態で加熱されると、化合物のスクロースは元素である炭素と化合物の水に分解されます。 塩化銀（ I ）は、光の吸収によってその元素である銀、塩素に分解できる白色の固体です。  
 結合された元素の特性は、自由な状態または結合されていない状態の特性とは異なります。たとえば、糖の結晶 ( スクロース ) は、結合していない状態では黒色の個体である炭素元素と、結合していない状態では無色の気体となる水素と酸素という２つの元素が、化学的に組み合わさって生まれた化合物です。 遊離ナトリウムは、軟らかく光沢のある金属固体であり、遊離塩素は、黄緑色の気体である元素で、それらが組み合わさって白い結晶性固体である塩化ナトリウム（テーブル塩）を形成します。 
 
 <h4>混合物：均一および不均一  </h4>
 
 均一混合物は、溶液とも呼ばれ、均一な組成を示し、全体的に同じように見えます。 溶液の例としては水、砂糖、着色料、香味料から成っているスポーツドリンクで、 電解質が均一に混合されています。 スポーツドリンクの一滴一滴には、同じ量の水、砂糖、その他の成分が含まれているため、同じ味がします。 一方でスポーツドリンクの組成はさまざまです。多少砂糖や香料などの成分は違いますが、どれもスポーツドリンクです。 他の均一な混合物の例は空気、メープルシロップ、ガソリンおよび食塩水の溶液などがあります。  
 
 組成がそれぞれの場所毎に異なる混合物は、不均一混合物と呼ばれます。 イタリアンドレッシングは不均一な混合物の例です。 その組成は様々な量の油、酢およびハーブから作られるので変化します。 そして混合物の中のある点と別の点では同じではありません - 1滴の中はほとんど酢かもしれないですが、違う１滴は油と酢が分離し、ハーブが沈殿するのでほとんど油とハーブだけかもしれません。 混合物の他の例としては、チョコレートチップクッキー（チョコレート、ナッツ、クッキー生地が別々になっているのが見える）や花崗岩（石英、雲母、長石などが見える）があります。  
 
 均一と不均一を問わず、あらゆる混合物は、物理的な手段で成分の固有な性質を変えずに純粋な成分に分離することができます。 元素の数は 100 余りですが、これら元素のさまざまな組み合わせによって、数千万種類もの化合物が生成されます。 各化合物には特定の組成があり、他のすべての化合物とは異なる明確な化学的特性と物理的特性を持っています。 そして、当然、異なる混合物を作るために、元素および化合物を結合する無数の方法があります。 
 
 このテキストは <a href="https://openstax.org/books/chemistry-2e/pages/1-2-phases-and-classification-of-matter">、 Openstax 、 Chemistry 2e 、 Section 1.2 ： Phases and Classification of Matter から引用しています。  </a>

物質:純粋な物質と混合物
その組成によると、問題は2つの大きなカテゴリに分類することができます - 純粋な物質と...

Education

JoVE Core

化学

Introduction: Matter and Measurement

序論：物質と測定

KEY TERMS AND CONCEPTS

主要用語と概念

matter: elements, compounds, and mixtures

Matter can be grouped by composition into pure substances and mixtures. A pure substance has a constant composition throughout and uniform properties. For example, any sample of sucrose has the same composition and the same physical properties, such as melting point, color, and sweetness, no matter where it is isolated from.

A mixture contains two or more kinds of matter in varying amounts. Its parts can be separated by physical changes, such as evaporation. The components keep their own identities, so the mixture is not a new substance in the same way a compound is.

Pure substances are divided into elements and compounds. Elements cannot be broken down into simpler substances by chemical changes. Iron, silver, gold, aluminum, sulfur, oxygen, and copper are examples of elements.

Compounds are pure substances that can be broken down by chemical changes. This breakdown may produce elements, other compounds, or both. Mercury(II) oxide can be heated to form mercury and oxygen, sucrose can break down into carbon and water when heated without air, and silver(I) chloride can be broken down by light into silver and chlorine.

The properties of combined elements are different from the properties of the elements in their free state. White crystalline sugar comes from carbon, hydrogen, and oxygen, but those elements look very different when uncombined. Free sodium is a soft, shiny metal, and free chlorine is a yellow-green gas, yet together they form sodium chloride, a white crystalline solid.

Mixtures can be homogeneous or heterogeneous. A homogeneous mixture, also called a solution, has a uniform composition and looks the same throughout. Sports drink is one example. It contains water, sugar, coloring, flavoring, and electrolytes mixed evenly, so each drop tastes the same. Its exact composition can still vary and remain a sports drink. Air, maple syrup, gasoline, and salt water are other homogeneous mixtures.

A heterogeneous mixture has a composition that varies from point to point. Italian dressing is one example, since the amounts of oil, vinegar, and herbs can differ and the parts may separate or settle. Chocolate chip cookies and granite are also heterogeneous mixtures because their different parts can be seen.

Any mixture, whether homogeneous or heterogeneous, can be separated into pure components by physical means without changing what the components are. There are just over 100 elements, but they combine in many ways to form tens of millions of compounds. Each compound has a specific composition and its own chemical and physical properties. Elements, compounds, and mixtures can combine in countless ways to make matter.

Matter: Elements, Compounds, and Mixtures

scientific laws and theories

How Science Explains Laws and Theories

Scientific laws and scientific theories describe science in two different ways. A law is a concise verbal or mathematical statement that summarizes many experimental observations. It describes or predicts aspects of the natural world that stay the same under the same conditions. A scientific theory is different because it explains why natural events happen. It is a unifying principle that gives a well-supported and testable explanation for a broad set of observations. Strong theories are the...

the scientific method

How Scientists Test a Hypothesis

Chemistry uses the scientific method to turn observations into testable answers. Scientists begin by observing a phenomenon in the physical world and then asking a question about it. This process helps explain everyday chemistry through evidence. A question leads to a hypothesis, which is a tentative explanation for what is being observed. Scientists often use earlier research and published literature to shape that idea. A strong hypothesis must be testable, meaning it can be supported by...

physical and chemical properties of matter

physical-and-chemical-properties-of-matter

Distinguishing Physical and Chemical Changes

Matter can be identified by its properties, which are the features that help us tell one substance from another. These properties fall into two main groups: physical properties and chemical properties. Understanding the difference helps explain how matter changes. A physical property is a feature of matter that is not linked to a change in chemical composition. Examples include density, color, hardness, melting point, boiling point, and electrical conductivity. Some physical properties can be...

what is energy?

Energy Forms and Conservation

Energy is a property of matter that appears in many forms. On Earth, most energy starts with the Sun. Plants capture light energy from the Sun and use photosynthesis to turn it into chemical energy. That stored energy can then move through living things and materials in several ways. People get energy from plant foods, and wood or coal, which come from fossilized plants, can be burned to produce heat and electricity. Energy is defined as the ability to do work. Work happens when a force moves...

classifying matter by state

States of Matter and Their Properties

States of matter help describe how matter behaves in chemistry. Matter is anything that has mass and takes up space. It is found everywhere, including air, water, soil, mountains, and even our bodies. The three common states on Earth are solid, liquid, and gas. A solid has a definite shape and a definite volume. Its particles, such as atoms or molecules, are packed very closely together and held in place by strong forces, so they only vibrate slightly. This tight arrangement makes solids...

measurement: standard units

Measurement: SI Units and Conversions

Measurement gives three kinds of information: a number, a unit, and an estimate of uncertainty. The number shows size or magnitude. The unit gives a standard for comparison. The uncertainty reflects possible error in the measurement. Numbers can be written in more than one way. A value may appear in decimal form or in scientific notation, which is also called exponential notation. For example, the maximum take-off weight of a Boeing 777-200ER airliner is 298,000 kilograms, or 2.98 × 10^5 kg. <br...

classifying matter by composition

Matter can be grouped by composition into pure substances and mixtures. A pure substance has a constant composition throughout and uniform properties. For example, any sample of sucrose has the same composition and the same physical properties, such as melting point, color, and sweetness, no matter where it is isolated from. A mixture contains two or more kinds of matter in varying amounts. Its parts can be separated by physical changes, such as evaporation. The components keep their own...

measurement: derived units

SI Units, Density, and Property Types

SI units and derived units help describe physical properties in chemistry. The International System of Units, or SI system, uses agreed-upon base units for seven fundamental properties: length, mass, time, temperature, electric current, amount of substance, and luminosity. Units made by combining these base units are called SI-derived units. Speed is one example. If distance is measured in meters and time in seconds, the derived unit for speed is meters per second, or m/s. Miles per hour is...

dimensional analysis

Using Conversion Factors to Cancel Units

Dimensional analysis is a method for using conversion factors to cancel units and solve measurement problems. It is also called the factor label method. The main rule is that units must be treated the same way as the numbers attached to them. A conversion factor is a ratio of two equal quantities written in different units. For example, 1 meter is equal to 1.0936 yards. That relationship can be used to build a factor that converts one unit into the other. When a value is multiplied or divided...

uncertainty in measurement: accuracy and precision

uncertainty-in-measurement-accuracy-and-precision

Measurement Error: Reading Results Correctly

Measurement error affects how scientists judge the quality of their results. Repeated measurements help show whether results are precise and accurate. A measurement is precise when repeated values are very similar. A measurement is accurate when it is very close to the true or accepted value. Precise values agree with each other, while accurate values agree with the true value. A pharmaceutical quality control chemist can use this idea to check machines that dispense 500 mL of cough syrup. The...

uncertainty in measurement: reading instruments

uncertainty-in-measurement-reading-instruments

Measurement Uncertainty and Significant Figures

Measurement uncertainty and significant figures show how carefully a value can be read from an instrument. Counting is different. If the number of objects does not change during counting, the result is exact. Defined quantities are exact too. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Most other measurements are not exact because the measuring process has limits. The result depends on the device used and on the person...

uncertainty in measurement: significant figures

uncertainty-in-measurement-significant-figures

Significant Figures and Rounding Rules

Significant figures and rounding rules help students report measurements with the right level of certainty. A measurement includes every digit that was actually measured, including the last uncertain digit. That is why a value can look simple but still carry useful information about the tool used to measure it. Zero can also be significant when it is part of a measured value. For example, if a scale reads 140 pounds to the nearest pound, the 1, 4, and 0 are all significant. Reporting...

key terms and concepts

Learn how matter is classified into elements, compounds, and mixtures. Explore pure substances, solutions, and examples like sports drink and Italian dressing.

Matter: Elements, Compounds, and Mixtures | JoVE K12

chemistry

JoVE Core 化学は、簡潔で理解しやすいアニメーションビデオレッスンを使用して、一般的な化学の概念を生き生きとしたものにします。さらに、活動する科学者のビデオでは、現在世界中の実験室で行われている古典的そして独創的な研究・実験をお見せします。

Matter and its Interactions

PS.Chm.1.1

Physical Science

PS.PSc.1.1

PS.PSc.1.3

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Classification of matter

Physical Geology

Minerals

Crystallinity (crystal structure)

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.a

Earth Science

ES.4

ES.4.a

PS.3

PS.3.a

Arizona Science Standards

High School

Earth and Space Science

HS.E1

HS.E1U1.12

HS.E1U1.13

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

New Jersey Student Learning Standards for Science

Earth's Place in the Universe

HS-ESS1-2

Texas Essential Knowledge and Skills

CHEM.2

CHEM.2.A

Alabama Course of Study Science

Matter and Its Interactions

9-12.PS.3.5

9-12.PS.3.5.a

Next Generation Science Standards

HS-PS1-5

HS-PS1-4

Chemistry and Physics

IPC.7

IPC.7.C

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

South Carolina College and Career Ready Science Standards

C-PS1-1

C-PS1-2

Earth and Space Science (ESS)

Earth’s Systems

E-ESS2-2.

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Chemical Reactions

HS-PS1-2.

Georgia Standards of Excellence

SPS5.

States of Matter

Classifying Matter by State

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Matter: Pure Substances and Mixtures
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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

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Intermolecular vs Intramolecular Forces

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Intermolecular Forces

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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.

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 ...

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 ...

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 ...

using-differential-scanning-calorimetry-to-measure-changes-in-enthalpy

Using Differential Scanning Calorimetry to Measure Changes in Enthalpy

Source: Laboratory of Dr. Terry Tritt &#8212; Clemson University
Differential Scanning Calorimetry (DSC) is a method of thermodynamic analysis based on ...

Hess's Law

There are two ways to determine the amount of heat involved in a chemical change: measure it experimentally, or calculate it from other experimentally ...

Standard Enthalpy of Formation

Enthalpy changes are typically tabulated for reactions in which both the reactants and products are at the same conditions. A standard state is a commonly ...

Enthalpies of Reaction

Hess&rsquo;s law can be used to determine the enthalpy change of any reaction if the corresponding enthalpies of formation of the reactants and products ...

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

PS.Chm.7.2

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Definition and Measurement of Pressure: Atmospheric Pressure, Barometer, and Manometer

Gas pressure is caused by force exerted by gas molecules colliding with the surfaces of objects. Although the force of each collision is very small, any ...

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Gas Laws: Boyle's, Gay-Lussac, Charles', Avogadro's, and Ideal Gas Law

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Applications of the Ideal Gas Law: Molar Mass, Density, and Volume

The volume occupied by one mole of a substance is its molar volume. The ideal gas law, PV = nRT, &nbsp;suggests that the volume of a given quantity of gas ...

Use mathematics and computational thinking to explain the relationships among pressure, temperature, volume, and quantity of gas, both qualitatively and quantitatively.

PS.Chm.7.3

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

Matter: Elements, Compounds, and Mixtures

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