Name: how gas pressure, volume, and temperature change
Uploaded: 2020-09-03T13:38:26.000Z
Duration: 3 min 19 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.7.3

gas-laws-boyle-s-gay-lussac-charles-avogadro-s-and-ideal-gas-law

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

As leis simples do gás manipulam as quatro propriedades interdependentes dos gases pressão, temperatura, volume, e o número de mols para derivar relações entre os pares de propriedades enquanto se mantêm as outras constantes. De acordo com a lei de Boyle, quando a temperatura e o número de mols de um gás são mantidas constantes, a pressão e o volume mostram uma relação inversa. À medida que o volume diminui, a pressão exercida pelo gás aumenta.O produto de P e V portanto, equivale a uma constante. Sob dois conjuntos diferentes de condições, o produto da pressão e do volume iniciais e o produto da pressão e do volume final são iguais. Agora, se o volume e o número de mols for constante, a pressão e a temperatura estabelecem uma relação direta.À medida que a temperatura sobe, as partículas movem-se mais rapidamente e existem colisões de alta energia mais frequentemente, sendo que a pressão aumenta. Portanto, a proporção de Pressão e Temperatura é igual a uma constante. Esta é a lei de Gay-Lussac, que, às vezes, é denominada de a lei de Amonton.Sob dois conjuntos diferentes de condições, a proporção entre a pressão e a temperatura iniciais e a proporção entre a pressão e a temperatura finais são iguais. A seguir, consideremos um balão que é cheio com um número fixo de mols de um gás. A pressão externa da atmosfera é constante.De acordo com a lei de Charles, se os mols e a pressão se mantiverem constantes, o volume de um gás e a sua temperatura em Kelvin estabelecem uma relação direta. Com o aumento da temperatura, as partículas de gás movem-se mais rapidamente. resultando num maior número de colisões e aumentando o volume do balão.Por outro lado, baixar a temperatura faz com que o balão encolha e diminua de volume. A proporção de Volume e Temperatura é igual a uma constante. Sob dois conjuntos diferentes de condições, a proporção entre o volume e a temperatura iniciais e a proporção entre o volume e a temperatura final são iguais.Agora, suponhamos que o balão é cheio com mais ar. De acordo com a lei de Avogadro, quando a pressão e a temperatura são mantidas constantes, o volume do gás e o número de mols estabelecem uma relação direta. O aumento do número de mols aglomera as partículas, o que resulta num maior número de colisões.Isto força o balão a expandir o seu volume para acomodar as partículas de gás. A proporção entre o volume e o número de mols, portanto, equivale a uma constante. Sob dois conjuntos diferentes de condições, a proporção entre o volume e o número de mols iniciais e a proporção entre o volume e o número de mols finais são iguais.Combinando as expressões das três leis do gás, e substituindo o sinal de proporcionalidade ao incorporar a constante de gás ideal R, dá origem à lei do gás ideal. R tem o mesmo valor para todos os gases, e é igual a 8, 314 Joules por mole Kelvin ou 0, 08206 litros-pressão atmosférica por mol-Kelvin.

leis de gases

Através de experiências, os cientistas estabeleceram as relações matemáticas entre pares de variáveis, tais como pressão e temperatura, pressão e volume, volume e temperatura, volume e moles, que se mantêm para um gás ideal.

<h4>Pressão e Temperatura: Lei de Gay-Lussac (Lei de Amontons)</h4>

Imagine encher um recipiente rígido preso a um manómetro de pressão com gás e, em seguida, vedar o recipiente de modo a que nenhum gás possa sair. Se o recipiente for arrefecido, o gás no interior fica do mesmo modo mais frio e observa-se que a sua pressão diminui. Uma vez que o recipiente é rígido e bem vedado, tanto o volume como o número de moles de gás permanecem constantes. Se a esfera for aquecida, o gás no interior fica mais quente e a pressão aumenta.

A temperatura e a pressão estão relacionadas linearmente, e essa relação é observada para qualquer amostra de gás confinada em um volume constante. Se a temperatura estiver na escala de kelvin, então P e T são diretamente proporcionais (mais uma vez, quando o volume e moles de gás são mantidos constantes); se a temperatura na escala de kelvin aumentar por um determinado factor, a pressão do gás aumenta pelo mesmo factor.

Esta relação de pressão-temperatura para os gases é conhecida como lei de Gay-Lussac. A lei afirma que a pressão de uma determinada quantidade de gás é diretamente proporcional à sua temperatura na escala de kelvin quando o volume é mantido constante. Matematicamente, isto pode ser escrito como: 

<img alt="Eq1" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-01.png" style="height: 40px;" />

onde k é uma constante de proporcionalidade que depende da identidade, quantidade, e volume do gás. Para um volume constante e confinado de gás, a relação P/T é então constante (ou seja, P/T = k). Se o gás estiver inicialmente na ‘Condição 1’ (com P = P1 and T = T1) e mudar para a ‘Condição 2’ (com P = P2 and T = T2), então

<img alt="Eq2" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-02.png" style="height: 40px;" />

Por conseguinte,  

<img alt="Eq3" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-03.png" style="height: 40px;" />

Note que para qualquer cálculo de lei de gases, as temperaturas devem estar na escala de kelvin. 

<h4>Volume e Temperatura: A Lei de Charles</h4>

Se um balão estiver cheio de ar e selado, o balão contém uma quantidade específica de ar à pressão atmosférica (1 atm). Se o balão for colocado em um frigorífico, o gás de dentro fica frio, e o balão encolhe (embora a quantidade de gás e a sua pressão permaneçam constantes). Se o balão ficar muito frio, ele irá encolher muito. Quando é aquecido, o balão irá expandir-se novamente.

Este é um exemplo do efeito da temperatura no volume de uma determinada quantidade de gás confinado a uma pressão constante. O volume aumenta à medida que a temperatura aumenta e o volume diminui à medida que a temperatura diminui.

A relação entre o volume e a temperatura de uma determinada quantidade de gás a uma pressão constante é conhecida como lei de Charles. A lei afirma que o volume de uma determinada quantidade de gás é diretamente proporcional à sua temperatura na escala de kelvin quando a pressão é mantida constante.

Matematicamente, isto pode ser escrito como:

<img alt="Eq4" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-04.png" style="height: 40px;" />

onde k é uma constante de proporcionalidade que depende da quantidade e pressão do gás. Para um gás confinado com uma pressão constante, a relação V/T é constante.

<h4>Volume e Pressão: A Lei de Boyle</h4>

Se uma seringa hermética estiver parcialmente cheia de ar, a seringa contém uma quantidade específica de ar a uma temperatura constante, por exemplo 25 °C. Se o êmbolo for pressionado lentamente enquanto a temperatura permanece constante, o gás da seringa é comprimido em um volume mais pequeno e a sua pressão aumenta. Se o êmbolo for extraído, o volume do gás aumenta e a pressão diminui.

Diminuir o volume de um gás contido aumentará sua pressão, e aumentar o seu volume diminuirá sua pressão. Se o volume aumentar por um determinado factor, a pressão diminui pelo mesmo factor e vice-versa. Portanto, a pressão e o volume apresentam proporcionalidade inversa: Aumentar a pressão resulta na diminuição do volume do gás. Matematicamente isto pode ser escrito:

<img alt="Eq5" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-05.png" style="height: 40px;" />

onde k é uma constante. Um gráfico de P versus V exibe uma hipérbole. Gráficos com linhas curvas são difíceis de ler com precisão a valores baixos ou altos das variáveis, sendo mais difíceis de usar na adaptação de equações teóricas e parâmetros aos dados experimentais. Por essas razões, os cientistas muitas vezes tentam encontrar uma maneira de “linearizar” os seus dados. Graficamente, a relação entre a pressão e o volume é mostrada pela apresentação inversa da pressão versus o volume, ou o inverso do volume versus a pressão.

A relação entre o volume e a pressão de uma determinada quantidade de gás a uma temperatura constante é dada pela lei de Boyle: O volume de uma determinada quantidade de gás mantido a uma temperatura constante é inversamente proporcional à pressão sob a qual é medida.

<h4>Moles de Gás e Volume: A Lei de Avogadro</h4>

O cientista Italiano Amedeo Avogadro avançou uma hipótese em 1811 para explicar o comportamento dos gases, afirmando que volumes iguais de todos os gases, medidos nas mesmas condições de temperatura e pressão, contêm o mesmo número de moléculas. Ao longo do tempo, esta relação foi apoiada por muitas observações experimentais expressas pela lei de Avogadro: Para um gás confinado, o volume (V) e o número de moles (n) são diretamente proporcionais se a pressão e a temperatura se mantiverem constantes.

Na forma de equação, isto é escrito como:

<img alt="Eq6" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-06.png" style="height: 40px;" />

Os relacionamentos matemáticos também podem ser determinados para os outros pares de variáveis, como P versus n e n versus T.

<h4>A Lei de Gás Ideal</h4>

A combinação destas quatro leis produz a lei de gás ideal, uma relação entre a pressão, o volume, a temperatura, e o número de moles de um gás:

<img alt="Eq7" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-07.png" style="height: 40px;" />

Aqui, R é uma constante chamada de constante de gás ideal ou constante de gás universal. As unidades usadas para expressar pressão, volume, e temperatura determinam a forma adequada da constante de gás conforme exigido pela análise dimensional. Os valores mais comuns de R são 0,08206 L⋅atm mol–1⋅K–1 e 8,314 kPa⋅L mol–1⋅K–1.

Diz-se que os gases cujas propriedades de P, V e T são descritas com precisão pela lei de gás ideal (ou outras leis de gases) apresentam comportamento ideal ou aproximam-se das características de um gás ideal. Um gás ideal é uma construção hipotética que só é razoável para gases sob condições de pressão relativamente baixa e temperatura elevada.

A equação de gás ideal contém cinco termos, a constante de gás R e as propriedades variáveis P, V, n e T. A especificação de quaisquer quatro destes termos permitirá o uso da lei de gás ideal para calcular o quinto termo. 

Se o número de moles de um gás ideal for mantido constante sob dois conjuntos diferentes de condições, obtém-se uma relação matemática útil chamada lei de gás combinada (usando unidades de atm, L, e K): 

<img alt="Eq8" src="https://www.jove.com/files/core/CDNSource/lessons/1036/1036_Equations-08.png" style="height: 40px;" />

Ambos os conjuntos de condições são iguais ao produto de n × R (em que n é o número de moles do gás e R é a constante da lei de gás ideal).

Este texto é adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/9-2-relating-pressure-volume-amount-and-temperature-the-ideal-gas-law">Openstax, Chemistry 2e, Section 9.2: Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law</a>.

Leis de Gases

Por meio de experimentos, os cientistas estabeleceram as relações matemáticas entre pares de variáveis, como pressão e temperatura, pressão e ...

Education

JoVE Core

Química

Gases

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

how gas pressure, volume, and temperature change

Gas pressure, volume, temperature, and amount are linked by several gas laws. Scientists found these relationships by studying how a confined gas changes when one variable is held constant and another changes. These patterns apply to an ideal gas, which is a useful model for gases under low pressure and high temperature.

Gay-Lussac’s law, also called Amontons’s law, connects pressure and temperature. If gas is trapped in a rigid container, the volume and number of moles stay constant. When the gas is cooled, its pressure drops. When it is heated, its pressure rises. On the kelvin scale, pressure and temperature are directly proportional, so the ratio P/T stays constant.

Charles’s law describes the link between volume and temperature at constant pressure. A sealed balloon in a refrigerator shrinks because the gas inside gets colder. When the balloon warms, it expands again. In this case, the amount of gas and the pressure stay constant, while volume changes with temperature. On the kelvin scale, volume and temperature are directly proportional, so V/T remains constant.

Boyle’s law explains the relationship between pressure and volume at constant temperature. An airtight syringe shows this effect clearly. Pressing the plunger compresses the gas into a smaller volume and raises the pressure. Pulling the plunger out lets the gas expand and lowers the pressure. This is an inverse relationship, so a larger volume means a lower pressure. A graph of P versus V is a hyperbola, which is hard to read at very high or low values. Scientists often linearize the data by plotting inverse pressure or inverse volume instead.

Avogadro’s law connects volume and the number of moles of gas. Amedeo Avogadro proposed in 1811 that equal volumes of gases, measured at the same temperature and pressure, contain the same number of molecules. For a confined gas, volume and moles are directly proportional when pressure and temperature stay constant. Other pairs of variables, such as pressure versus moles and moles versus temperature, can also be related.

The ideal gas law combines these relationships into one equation that links pressure, volume, temperature, and moles. It uses the gas constant R, which has different values depending on the units, such as 0.08206 L·atm mol−1·K−1 or 8.314 kPa·L mol−1·K−1. Gases that closely follow this model show ideal behavior. The ideal gas law uses five terms, so knowing any four lets you solve for the fifth. If the number of moles stays the same, the combined gas law is also useful for comparing two sets of gas conditions.

How Gas Pressure, Volume, and Temperature Change

how-gas-pressure-volume-and-temperature-change

definition and measurement of pressure: atmospheric pressure, barometer, and manometer

definition-measurement-pressure-atmospheric-pressure-barometer

Pressure Units and Tools for Gas Measurement

Pressure is the force applied to a given area, and gas pressure comes from gas molecules colliding with surfaces. Each collision is tiny, but many collisions over a small area can create high pressure. Pressure increases when force increases or when the area gets smaller. It decreases when force drops or when the area gets larger. Pressure is measured in pascals, or Pa, in the SI system. One pascal equals 1 newton per square meter, and a newton is a unit of force equal to 1 kg·m/s2. A pascal...

gas laws: boyle's, gay-lussac, charles', avogadro's, and ideal gas law

Gas pressure, volume, temperature, and amount are linked by several gas laws. Scientists found these relationships by studying how a confined gas changes when one variable is held constant and another changes. These patterns apply to an ideal gas, which is a useful model for gases under low pressure and high temperature. Gay-Lussac’s law, also called Amontons’s law, connects pressure and temperature. If gas is trapped in a rigid container, the volume and number of moles stay constant. When the...

applications of the ideal gas law: molar mass, density, and volume

applications-of-the-ideal-gas-law-molar-mass-density-and-volume

Ideal Gas Law at STP and Gas Density

The ideal gas law links pressure, volume, number of moles, and temperature. It helps explain how gas volume changes when pressure or temperature changes. At standard temperature and pressure, or STP, the values are 273.15 K and 1 atm. At STP, one mole of an ideal gas occupies about 22.4 L. This is called the standard molar volume. The gas can be hydrogen, oxygen, argon, or carbon dioxide, and the volume is still about 22.4 liters. Half a mole occupies 11.2 L, and 2 moles occupy 44.8 L. The...

mixtures of gases: dalton's law of partial pressures and mole fractions

mixtures-of-gases-dalton-s-law-of-partial-pressures-and-mole-fractions

Gas Pressure in Mixtures: Partial Pressures

Gas pressure in mixtures is described by partial pressure and mole fraction. When gases do not chemically react, each gas in the mixture acts as if it were alone in the container. The pressure from one gas is called its partial pressure. For a mixture of three gases, A, B, and C, the total pressure equals the sum of their partial pressures: PA, PB, and PC. This is Dalton's law of partial pressures. It states that the total pressure of a mixture of ideal gases is the sum of the pressures from...

chemical stoichiometry and gases: using ideal gas law to determine moles

chemical-stoichiometry-gases-using-ideal-gas-law-to-determine

Stoichiometry of Gases with the Ideal Gas Law

Chemical stoichiometry links the amounts of reactants and products in a chemical reaction. For gases, those amounts can also be measured by volume. If a gas’s volume, pressure, and temperature are known, the ideal gas equation can be used to find the number of moles present. The same idea works in reverse. If the moles of a gas are known, its volume can be found at any temperature and pressure. The transcript gives an example using 8.88 g of gallium reacting with excess hydrochloric acid.

basic postulates of kinetic molecular theory: particle size, energy, and collision

basic-postulates-kinetic-molecular-theory-particle-size-energy

Kinetic Molecular Theory and Gas Behavior

Kinetic molecular theory explains gas behavior at the particle level. It gives a microscopic model for what happens when pressure or temperature changes. Gas laws describe how macroscopic properties change, but they do not explain why those changes happen. The theory was put into a complete form by Rudolf Clausius in 1857. It was built from hundreds of experimental observations about gases. Those observations helped explain the different gas laws through a few basic postulates. One key idea...

kinetic molecular theory and gas laws explain properties of gas molecules

kinetic-molecular-theory-gas-laws-explain-properties-gas

Gas Pressure Patterns in Kinetic Molecular Theory

Kinetic molecular theory explains gas pressure by linking it to the motion of gas molecules. Gas pressure comes from rapidly moving molecules hitting the walls of a container. It depends on how many molecules strike a unit area in a given time. The theory also helps explain the main gas laws. In Gay-Lussac’s law, also called Amontons’s law, raising temperature increases the average speed and kinetic energy of gas molecules. If volume stays constant, the molecules collide with the walls more...

kinetic molecular theory: molecular velocities, temperature, and kinetic energy

kinetic-molecular-theory-molecular-velocities-temperature-kinetic

Gas Particle Speed Distributions and Temperature

Gas particle speed distributions and temperature are key ideas in the kinetic molecular theory. This theory explains the gas laws by describing how gas molecules move, collide, and share energy. Gas molecules do not all move at the same speed. A gas sample has an average speed and an average kinetic energy, but individual molecules move at different speeds. Their collisions are elastic, which means momentum is conserved. Because so many molecules collide, the overall speed distribution stays...

behavior of gas molecules: molecular diffusion, mean free path, and effusion

behavior-gas-molecules-molecular-diffusion-mean-free-path

Gas Particle Motion, Diffusion, and Effusion

Gas particle motion, diffusion, and effusion explain how gases spread and escape in everyday settings. Gas molecules move at very high speeds, but they collide with other gas molecules and change direction many times before reaching a target. At room temperature, a gas molecule can experience billions of collisions each second. The mean free path is the average distance a molecule travels between collisions. This distance becomes larger when pressure decreases. In general, the mean free path...

real gases: effects of intermolecular forces and molecular volume deriving van der waals equation

real-gases-effects-intermolecular-forces-molecular-volume-deriving

Real Gases: When the Ideal Gas Law Breaks Down

Real gases are gases that do not always follow the ideal gas law, PV = nRT, especially when pressure is high or temperature is low. The ideal gas model assumes gas particles have no attractive or repulsive forces and take up negligible space compared with the container. At room temperature and 1 atm or less, many gases behave close to ideally. When conditions change, the measured relationships between pressure, volume, and temperature can drift away from the ideal prediction. One way to see...

key terms and concepts

Explore Boyle’s, Charles’s, Gay-Lussac’s, and Avogadro’s laws with simple gas examples, plus the ideal gas law for pressure, volume, temperature, and moles.

How Gas Pressure, Volume, and Temperature Change | JoVE K12

chemistry

JoVE Core - Química dá vida a conceitos gerais de química usando vídeos de animação fáceis de entender. Além disso, nos vídeos Cientistas em ação, demonstramos experimentos de pesquisa clássicos e originais realizados atualmente por cientistas em laboratórios em todo o mundo.

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Interactions Of Matter

Gas laws

Tennessee Academic Standards

High School

Matter and Its Interactions

CHEM1.PS1.5

CHEM1.PS1.6

Virginia  Standards of Learning

HIgh School

CH.6

CH.6.b

Minnesota Academic Standards in Science

2.2.1 9C.1.2.1.1

Arizona Science Standards

Physical Science

HS+C.P1

HS+C.P1U1.3

Texas Essential Knowledge and Skills

CHEM.10

CHEM.10.B

Alabama Course of Study Science

9-12.C.1.4.e

9-12.C.4.7.b

Earth and Space Science

Earth's Systems

9-12.ESS.2.7.c

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Structure and Properties of Matter

HS-PS1-9.

Georgia Standards of Excellence

SC5.

gas-laws-pressure-volume-temperature-and-moles

Gas Laws: Pressure, Volume, Temperature, and Moles

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

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

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 ...

Through experiments, scientists established the mathematical relationships between pairs of variables, such as pressure and temperature, pressure and ...

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 ...

Mixtures of Gases: Dalton's Law of Partial Pressures and Mole Fractions

Unless individual gases chemically react with each other, the individual gases in a mixture of gases do not affect each other&rsquo;s pressure. Each gas ...

Chemical Stoichiometry and Gases: Using Ideal Gas Law to Determine Moles

Chemical stoichiometry describes the quantitative relationships between reactants and products in chemical reactions.

In addition to measuring quantities ...

Basic Postulates of Kinetic Molecular Theory: Particle Size, Energy, and Collision

The ideal-gas equation, which is empirical, describes the behavior of gases by establishing relationships between their macroscopic properties. For ...

Kinetic Molecular Theory and Gas Laws Explain Properties of Gas Molecules

The test of the kinetic molecular theory (KMT) and its postulates is its ability to explain and describe the behavior of a gas. The various gas laws ...

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 ...

Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion

Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many ...

Real Gases: Effects of Intermolecular Forces and Molecular Volume Deriving Van der Waals Equation

Thus far, the ideal gas law, PV = nRT, has been applied to a variety of different types of problems, ranging from reaction stoichiometry and empirical and ...

Ideal Gas Law

Source: Laboratory of Dr. Andreas Z&#252;ttel - Swiss Federal Laboratories for Materials Science and Technology
The ideal gas law describes the behavior ...

Derivation of the Ideal Gas Law
Gases are a fundamental state of matter. A gas is a collection of molecules that have a significant distance between their ...

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Preparation of the LaboratoryExpand
	Here, we show the laboratory preparation for 10 students ...

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Determining the Mass of the Unknown LiquidExpand
	According to the ideal gas law for a given ...

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

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

How Gas Pressure, Volume, and Temperature Change

Description

Transcript

Tags

More videos by Standards