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

Вещество состоит из атомов мельчайших основных единиц вещества и молекул, которые образуются путем соединения двух или более атомов вместе. По своему составу вещество можно разделить на две группы чистые вещества и смеси. По определению, вещество считается чистым, если оно состоит только из одного компонента с однородным составом.Например, возьмем водород. Водород состоит только из атомов водорода. Точно так же вода состоит только из молекул воды.Эти составы не меняются от образца к образцу. Чистые вещества можно разделить на два типа элементы и соединения, в зависимости от того, можно ли их расщепить. Элементы это чистые вещества, которые нельзя расщепить на более простые химическими средствами.Например, водород это элемент. Напротив, соединения это вещества, которые можно расщепить на составляющие только химическим путем. Например, воду, также являющуюся чистым веществом, можно химически разделить на два более простых вещества водород и кислород, то есть это соединение.На Земле соединения встречаются чаще, чем чистые элементы, потому что большинство элементов легко соединяются с другими элементами. Например, мел, которым пишут на доске, состоит из кальция, углерода и кислорода;сахар состоит из углерода, водорода и кислорода. Смеси, в отличие от чистых веществ, состоят из одного или нескольких компонентов.Их соотношение также может меняться от образца к образцу. Например, лимонад представляет собой смесь трех компонентов лимонного сока, сахара и воды и их пропорции можно изменять, чтобы напиток получился более или менее сладким. Сами смеси можно разделить на два типа гомогенные и гетерогенные, в зависимости от того, насколько равномерно смешиваются в них вещества.Гомогенная смесь имеет однородный состав и визуально выглядит одинаково по всей структуре. Ее часто называют раствором. Например, ложка соли при растворении в воде дает однородную смесь, поскольку каждая капля этой смеси имеет одинаковый состав.Точно так же и лимонад это однородная смесь. В гетерогенной смеси компоненты распределены неравномерно, и поэтому состав варьируется от одного компонента к другому. Например, песок, смешанный с железными опилками здесь разные части этой смеси, вероятно, будут содержать разное количество железных опилок и песка.В любом случае любую смесь, будь то гомогенную или гетерогенную, можно разделить на чистые компоненты физическими средствами без изменения состава компонентов. Например, соль можно излечь из водного раствора путем выпаривания. Аналогичным образом железные опилки можно отделить от песка с помощью магнита.

Классификация вещества по составу

<h4>Материя: Чистые вещества и смеси </h4>
 
 В соответствии с его составом, вещество может быть классифицировано по двум широким категориям — чистые вещества и смеси.  
 
 Чистое вещество — это форма материи, которая имеет постоянный состав с однородными свойствами. Например, любой образец сахарозы имеет одинаковый состав и такие же физические свойства, как температура плавления, цвет и сладость, независимо от источника, из которого он был получен.  
 
 Смесь состоит из двух или более типов вещества, которые могут присутствовать в различных количествах и могут быть разделены физическими изменениями, такими как испарение. Компоненты в смеси сохраняют свою индивидуальность. 
 
 <h4>Чистые вещества: Элементы и соединения </h4>
 
 Чистые вещества можно разделить на два класса: Элементы и соединения. Чистые вещества, которые невозможно разбить на более простые вещества в результате химических изменений, называются элементами. Железо, серебро, золото, алюминий, сера, кислород и медь являются элементами. 
 
 Чистые вещества, которые могут быть разбиты химическими изменениями, называются соединениями. В результате этого распада могут образоваться либо элементы, либо другие соединения, либо и то, и другое. Оксид ртути(II), оранжевое, кристаллическиое твердое вещество, может разложиться под воздействием тепла в элементы ртути и кислорода. При нагревании в отсутствие воздуха соединение сахароза расщепляется на элемент углерод и соединение воду. Хлорид серебра(I) – это белое твердое вещество, которое можно разделить на элементы, серебро и хлор, путём поглощения света.  
 
 Свойства объединенных элементов отличаются от свойств в свободном или несвободном состоянии. Например, белый кристаллический сахар (сахароза) представляет собой соединение, полученное в результате химического сочетания элемента углерода, который является черным твердым в одной из его некомбинированных форм, и двух других элементов, водорода и кислорода, которые в чистом виде являются бесцветными газами. Свободный натрий, элемент, мягкое, блестящее, металлическое твёрдое вещество, и свободный хлор, элемент, который представляет собой желто-зеленый газ, соединяются с образованием хлорида натрия (настольная соль), соединения, которое является белым кристаллическим твердым веществом. 
 
 <h4>Смеси: Однородные и неоднородные  </h4>
 
 Однородная смесь, также называемая раствором, имеет однородный состав и выглядит визуально одинаково по всему объему. Примером раствора является спортивный напиток, состоящий из воды, сахара, краски, ароматизатора, и электролитов, смешанных друг с другом равномерно. Каждая капля спортивного напитка на вкус одинакова, потому что каждая капля содержит одинаковое количество воды, сахара и других компонентов. Имейте в виду, что состав спортивного напитка может быть разным — он может быть приготовлен с несколько большим или меньшим содержанием сахара, ароматизатора или других компонентов и при этом оставаться спортивным напитком. К другим примерам однородных смесей относятся воздух, кленовый сироп, бензин и раствор соли в воде.  
 
 Смесь с составом, изменяющимся от точки к точке, называется гетерогенной, или неоднородной смесью. Итальянская салатная заправка является примером неоднородной смеси. Её состав может быть разным, поскольку она может быть приготовлена из различных объемов масла, уксуса и трав. О не один и тот же от точки к точке во всей смеси—одна капля может быть в основном уксусом, тогда как другая капля может быть в основном маслом или травами, потому что масло и уксус разделяются, а травы оседают. Другими примерами неоднородных смесей являются шоколадные печенья с чипсами (в них можно увидеть отдельные кусочки шоколада, орехов и печенья) и гранит (в нём можно увидеть кварц, слюду, полевой шпат и многое другое).  
 
 Любая смесь, будь она однородная или неоднородная, может быть разделена на чистые компоненты физическими средствами без изменения идентичности компонентов. Хотя существует чуть более 100 элементов, десятки миллионов химических соединений являются результатом различных комбинаций этих элементов. Каждое соединение имеет определенный состав и обладает определенными химическими и физическими свойствами, отличающими его от всех других соединений. И, конечно же, существует бесчисленное множество способов комбинировать элементы и соединения для образования различных смесей. 
 
 Этот текст адаптирован из <a href=""https://openstax.org/books/chemistry-2e/pages/1-2-phases-and-classification-of-matter"">Openstax, Химия 2e, раздел 1.2: Фазы и классификация вещества.  </a>"

Вещество: Чистые вещества и смеси
По своему составу вещество можно классифицировать на две большие категории — чистые вещества и...

Education

JoVE Core

Химия

Один

Introduction: Matter and Measurement

Введение: Вещество и измерения

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

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

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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

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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

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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 Chemistry brings general chemistry concepts to life using concise and easy-to-understand animated video lessons. Plus, in the scientist-in-action videos, we demonstrate classical and original research experiments performed in today's laboratories worldwide.

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Physical Science

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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

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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.

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New York State Science Learning Standards

HS. Chemical Reactions

HS-PS1-2.

Georgia Standards of Excellence

SPS5.

States of Matter

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, ...

Matter: Pure Substances and Mixtures
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Intermolecular vs Intramolecular Forces

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Surface Tension, Capillary Action, and Viscosity

Surface Tension
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States of Matter and Phase Changes

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Phase Transitions

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Phase Transitions: Sublimation and Deposition

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Heating and Cooling Curves

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First Law of Thermodynamics

Energy Conservation

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Internal Energy

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Quantifying Heat

Thermal Energy&#160;

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Enthalpy

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Thermochemical Equations

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Constant Pressure Calorimetry

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Constant Volume Calorimetry

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Using Differential Scanning Calorimetry to Measure Changes in Enthalpy

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Hess's Law

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Standard Enthalpy of Formation

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Enthalpies of Reaction

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PS.Chm.7.2

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PS.Chm.7.3

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

Matter: Elements, Compounds, and Mixtures

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