Name: distinguishing physical and chemical changes
Uploaded: 2020-09-03T13:38:25.000Z
Duration: 2 min 57 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.7.1

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

Las características que nos ayudan a distinguir entre los tipos de materia se conocen como propiedades. La materia presenta dos tipos de propiedades:físicas y químicas. Las propiedades físicas de la materia pueden medirse y observarse sin cambiar la composición o la naturaleza de la misma.Olor, sabor, color, aspecto, dureza, densidad, puntos de ebullición y fusión, y conductividad eléctrica son ejemplos de propiedades físicas. Algunas de estas propiedades se pueden observar sin cambiar el estado físico de la materia. Entonces, cuando decimos que el helio es más ligero que el aire, nos referimos a una propiedad física.De forma similar, el olor de la gasolina también es una propiedad física. Otras de estas propiedades únicamente se pueden observar cuando la materia sufre cambios físicos. Por ejemplo, el oro puro en su estado sólido está hecho de átomos de oro muy compactados.Pero, cuando se derrite a alta temperatura, su estado cambia de sólido a líquido. No obstante, este líquido sigue estando compuesto por átomos de oro, es decir, es un cambio físico. De la misma manera, cuando el agua líquida se congela y se vuelve hielo sólido, la composición química tanto del agua como del hielo sigue siendo la misma.Por consiguiente, los cambios físicos solo alteran el estado de la materia o sus condiciones físicas sin modificar su composición química. Machacar, moler, rebanar, mezclar, imantar o desimantar son otras formas comunes de cambiar las condiciones físicas de la materia. Las propiedades químicas de la materia, por otra parte, son características que solo pueden medirse u observarse cuando la sustancia sufre un cambio en su composición química.Corrosividad, inflamabilidad, toxicidad, acidez o reactividad química son ejemplos de estas propiedades. Para identificar una propiedad química, debemos buscar un cambio químico. Estos cambios implican reacciones químicas y, a menudo, se pueden observar con los cambios de color y olor.Por ejemplo, cuando una moneda de cobre de un centavo se expone al aire y al agua, se produce un cambio químico. El cobre pasa por una serie de reacciones químicas, una de las cuales se muestra aquí, y se forma una capa de pátina azul verdosa sobre el centavo, que es marrón por naturaleza. Por lo tanto, los cambios químicos producen formas totalmente nuevas de la materia que son distintas a la materia que había originalmente.Por ejemplo, la inflamabilidad de la gasolina es una propiedad química evidente por los cambios químicos que sufre la composición de la gasolina cuando se quema, lo que la convierte en sustancias totalmente nuevas:dióxido de carbono y agua, principalmente.

propiedades físicas y químicas de la materia

Las características que nos permiten distinguir una sustancia de otra se denominan propiedades.
 
 <h4>Propiedades físicas de la materia</h4>
 
 Una propiedad física es una característica de la materia que no está asociada con un cambio en su composición química. Algunos ejemplos conocidos de propiedades físicas son la densidad, el color, la dureza, los puntos de fusión y ebullición y la conductividad eléctrica. Podemos observar algunas propiedades físicas, como la densidad y el color, sin cambiar el estado físico de la materia observada. Otras propiedades físicas, como la temperatura de fusión del hierro o la temperatura de congelación del agua, sólo pueden observarse cuando la materia sufre un cambio físico. 
 
 Un cambio físico es un cambio en el estado o propiedades de la materia sin ningún cambio acompañante en su composición química (las identidades de las sustancias contenidas en la materia). Observamos un cambio físico cuando, por ejemplo, la cera se derrite, el azúcar se disuelve en el café y el vapor se condensa en agua líquida. Otros ejemplos de cambios físicos incluyen la magnetización y desmagnetización de metales (como se hace con las etiquetas de seguridad antirrobo comunes) y la molienda de sólidos en polvos. En cada uno de estos ejemplos, hay un cambio en el estado físico, la forma o las propiedades de la sustancia, pero ningún cambio en su composición química.
 
 <h4>Propiedades químicas de la materia</h4>
 
 El cambio de un tipo de materia en otro tipo (o la incapacidad de cambiar) es una propiedad química. Ejemplos de propiedades químicas incluyen inflamabilidad, toxicidad, acidez, reactividad (muchos tipos) y calor de combustión. El hierro, por ejemplo, se combina con el oxígeno en presencia de agua para formar óxido; el cromo no se oxida. La nitroglicerina es muy peligrosa porque explota fácilmente; el neón no representa casi ningún peligro porque es muy poco reactivo. 
 
 Para identificar una propiedad química, buscamos un cambio químico. Un cambio químico siempre produce uno o más tipos de materia que difieren de la materia presente antes del cambio. La formación de óxido es un cambio químico porque el óxido es un tipo diferente de materia que el hierro, el oxígeno y el agua presentes antes de la formación de óxido. La explosión de nitroglicerina es un cambio químico porque los gases producidos son tipos de materia muy diferentes de la sustancia original. Otros ejemplos de cambios químicos incluyen las reacciones que se realizan en un laboratorio (como la reacción del cobre con el ácido nítrico), todas las formas de combustión (quema), la maduración de las frutas así como los alimentos que se cocinan, digieren o se pudrieron. 
 
 Este texto es adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/1-3-physical-and-chemical-properties">Openstax, Química 2e, Sección 1,3: Propiedades Físicas y Químicas.</a>

Propiedades Físicas y Químicas de la Materia

Las características que nos permiten distinguir una sustancia de otra se denominan propiedades.

Propiedades físicas de la materia

Una propiedad física es ...

Education

Educación

JoVE Core

Química

Introduction: Matter and Measurement

Introducción: La materia y la medición

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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 observed without changing the state of the matter, such as density and color. Others appear only during a physical change, like the melting temperature of iron or the freezing temperature of water.

A physical change alters the state or form of matter without changing what the substance is made of. Wax melting, sugar dissolving in coffee, and steam condensing into liquid water are all physical changes. Magnetizing and demagnetizing metals, such as in anti-theft security tags, and grinding solids into powders are also physical changes. In each case, the material looks or behaves differently, but its chemical composition stays the same.

Chemical properties describe whether matter can change into a different type of matter, or resist that change. Common chemical properties include flammability, toxicity, acidity, reactivity, and heat of combustion. Iron reacts with oxygen and water to form rust, while chromium does not oxidize. Nitroglycerin explodes easily, but neon is very unreactive.

To identify a chemical property, we look for a chemical change. A chemical change produces one or more new kinds of matter that are different from the starting material. Rust formation is a chemical change because rust is not the same as iron, oxygen, or water. Nitroglycerin exploding is also a chemical change because the gases produced are different from the original substance. Other chemical changes include copper reacting with nitric acid, burning, fruit ripening, and food being cooked, digested, or rotting.

Distinguishing Physical and Chemical Changes

distinguishing-physical-and-chemical-changes

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

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: 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...

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 to tell physical properties from chemical properties using clear examples like melting, rusting, burning, and dissolving for grades 9–12.

Distinguishing Physical and Chemical Changes | JoVE K12

chemistry

JoVE Core Química da vida a los conceptos de química general mediante lecciones de vídeo basadas en animaciones, concisas y fáciles de entender. Además, en los vídeos de científicos en acción, se muestran experimentos de investigación clásicos y originales realizados en laboratorios de todo el mundo.

Physical Science

Matter and its Interactions

PS.PSc.1.3

Pennsylvania State Academic Standards

Earth and Space Science

Earth's Systems

3.3.9-12.K

Louisiana Student Standards for Science

High School

Matter And Its Interactions

HS-PS1-2

HS-PS1-7

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Study Of Matter

Classification of matter

Physical Geology

Minerals

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Properties of minerals (hardness, luster, cleavage, streak, crystal shape, fluorescence, flammability, density/specific gravity, malleability)

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.a

Earth Science

ES.4

ES.4.a

PS.3

PS.3.a

Physics

PH.9

PH.9.e

Arizona Science Standards

HS.E1

HS.E1U1.12

HS.E1U1.13

HS+C.P1

HS+C.P1U1.5

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-PS1-6

HS-PS1-4

Florida Department of Education

SC.912.P.8

SC.912.P.8.2

Chemistry and Physics

IPC.7

IPC.7.B

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

C-PS1-3.

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Motion and Stability: Forces and Interactions

C-PS2-6.

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

SC2.

Intermolecular vs. Intramolecular Forces

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 ...

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.

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 ...

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

PS.Chm.7.2

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

Distinguishing Physical and Chemical Changes

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