Temperature and heat

2018 ◽  
Author(s):  
Dennis Sherwood ◽  
Paul Dalby
Keyword(s):  
Equations Of State ◽  
Open Systems ◽  
Boltzmann Distribution ◽  
Ideal Gas ◽  
Heat Energy ◽  
Conservation Of Energy ◽  
Temperature Scales ◽  
Ideal Gas Law ◽  
Molecular Interpretation ◽  
The Ideal

Concepts of temperature, temperature scales and temperature measurement. The ideal gas law, Dalton’s law of partial pressure. Assumptions underlying the ideal gas, and distinction between ideal and real gases. Introduction to equations-of-state such as the van der Waals, Dieterici, Berthelot and virial equations, which describe real gases. Concept of heat, and distinction between heat and temperature. Experiments of Rumford and Joule, and the principle of the conservation of energy. Units of measurement for heat. Heat as a path function. Flow of heat down a temperature gradient as an irreversible and unidirectional process. ‘Zeroth’ Law of Thermodynamics. Definitions of isolated, closed and open systems, and of isothermal, adiabatic, isobaric and isothermal changes in state. Connection between work and heat, as illustrated by the steam engine. The molecular interpretation of heat, energy and temperature. The Boltzmann distribution. Meaning of negative temperatures.

Temperature, Pressure, Chemical Potential, and All That

2019 ◽  
pp. 99-112
Author(s):  
Robert H. Swendsen
Keyword(s):  
Chemical Potential ◽  
Equations Of State ◽  
Partial Information ◽  
Boltzmann Distribution ◽  
Ideal Gas ◽  
Fundamental Relation ◽  
Partial Derivatives ◽  
Ideal Gas Law ◽  
Pressure Chemical ◽  
Derivatives Of

The Maxwell–Boltzmann distribution of momentum is obtained from statistical mechanics. Expressions for the temperature, pressure, and chemical potential are formulated as partial derivatives of the entropy with respect to energy, volume, and particle-number. The temperature scale is derived from comparison with the ideal gas law. The concept of the fundamental relation is defined as an expression that contains all thermodynamic information about the system of interest. Its differential form is introduced. Equations of state contain partial information about the thermal properties of a system and can be expressed as partial derivatives of the fundamental relation. The function of thermometers, pressure gauges, and thermal reservoirs are derived from these principles.

Making sense of sensemaking: using the sensemaking epistemic game to investigate student discourse during a collaborative gas law activity

2021 ◽  
Author(s):  
Kevin H. Hunter ◽  
Jon-Marc G. Rodriguez ◽  
Nicole M. Becker
Keyword(s):  
Problem Solving ◽  
Conceptual Understanding ◽  
Ideal Gas ◽  
Interactive Simulation ◽  
Structural Components ◽  
Student Discourse ◽  
Coding Scheme ◽  
Making Sense ◽  
Ideal Gas Law ◽  
The Ideal

Beyond students’ ability to manipulate variables and solve problems, chemistry instructors are also interested in students developing a deeper conceptual understanding of chemistry, that is, engaging in the process of sensemaking. The concept of sensemaking transcends problem-solving and focuses on students recognizing a gap in knowledge and working to construct an explanation that resolves this gap, leading them to “make sense” of a concept. Here, we focus on adapting and applying sensemaking as a framework to analyze three groups of students working through a collaborative gas law activity. The activity was designed around the learning cycle to aid students in constructing the ideal gas law using an interactive simulation. For this analysis, we characterized student discourse using the structural components of the sensemaking epistemic game using a deductive coding scheme. Next, we further analyzed students’ epistemic form by assessing features of the activity and student discourse related to sensemaking: whether the question was framed in a real-world context, the extent of student engagement in robust explanation building, and analysis of written scientific explanations. Our work provides further insight regarding the application and use of the sensemaking framework for analyzing students’ problem solving by providing a framework for inferring the depth with which students engage in the process of sensemaking.

scholarly journals Modification of the Electron Entropy Production in a Plasma

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 935
Author(s):  
Juan F. García-Camacho ◽  
Gonzalo Ares de Parga ◽  
Karen Arango-Reyes ◽  
Encarnación Salinas-Hernández ◽  
Samuel Domínguez-Hernández
Keyword(s):  
Entropy Production ◽  
Equations Of State ◽  
Hermite Polynomials ◽  
Ideal Gas ◽  
Modified Equations ◽  
Modified Entropy ◽  
The Ideal

A modified expression of the electron entropy production in a plasma is deduced by means of the Kelly equations of state instead of the ideal gas equations of state. From the Debye–Hückel model which considers the interaction between the charges, such equations of state are derived for a plasma and the entropy is deduced. The technique to obtain the modified entropy production is based on usual developments but including the modified equations of state giving the regular result plus some extra terms. We derive an expression of the modified entropy production in terms of the tensorial Hermitian moments hr1…rm(m) by means of the irreducible tensorial Hermite polynomials.

What Happens When We have Winter Heating of Our Rooms?

2020 ◽  
Vol 02 (01) ◽  
pp. 2020001
Author(s):  
Dulli C. Agrawal
Keyword(s):  
Internal Energy ◽  
Old Age ◽  
Ideal Gas ◽  
Van Der Waals Gas ◽  
Constant Weight ◽  
Gas Laws ◽  
Ideal Gas Law ◽  
Marginal Change ◽  
Three Stages ◽  
The Ideal

The illustrious question by German Astrophysicist R. Emden, “Why do we have winter heating?” has been re-examined for air following both the ideal and imperfect gas laws; the internal energy of the air in the room remains unaffected in the former case whereas it increases marginally for the latter one. The findings corresponding to ideal gas law were correlated by Emden with the mass of a person which does not change even though food is constantly consumed. This example corresponds to adulthood when the mass of a person remains more or less constant. But the marginal change of internal energy in the case of van der Waals gas is consistent with three stages of a person — initially a person grows during childhood followed by adulthood when he has more or less constant weight and finally in old age, it deteriorates.

scholarly journals Percentile Study of χ Distribution. Application to Response Time Data

Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 514 ◽  
Author(s):  
Juan Carlos Castro-Palacio ◽  
Pedro Fernández-de-Córdoba ◽  
J. M. Isidro ◽  
Esperanza Navarro-Pardo ◽  
Romeo Selvas Aguilar
Keyword(s):  
Time Distribution ◽  
Dimensional Space ◽  
Reaction Times ◽  
Approximate Expression ◽  
Boltzmann Distribution ◽  
Ideal Gas ◽  
Practical Case ◽  
Time Data ◽  
School Aged Children ◽  
The Ideal

As a continuation of our previous work, where a Maxwell–Boltzmann distribution was found to model a collective’s reaction times, in this work we will carry out a percentile study of the χ distribution for some freedom ranging from k = 2 to k = 10. The most commonly used percentiles in the biomedical and behavioral sciences have been included in the analysis. We seek to provide a look-up table with percentile ratios, taken symmetrically about the median, such that this distribution can be identified in practice in an easy way. We have proven that these ratios do not depend upon the variance chosen for the k generating Gaussians. In general, the χ probability density, generalized to take any value of the variance, represents an ideal gas in a k-dimensional space. We also derive an approximate expression for the median of the generalized χ distribution. In the second part of the results, we will focus on the practical case of k = 3, which represents the ideal gas in physics, and models quite well the reaction times of a human collective. Accurately, we will perform a more detailed scrutiny of the percentiles for the reaction time distribution of a sample of 50 school-aged children (7200 reaction times).

Heat Transfer and Pressure Drop Through Nano-Fin Arrays in the Free-Molecular Flow Regime

2012 ◽  
Author(s):  
Michael James Martin
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Gas Flow ◽  
Ideal Gas ◽  
Molecular Flow ◽  
Ideal Gas Law ◽  
Transfer Equations ◽  
Flow Through ◽  
The One ◽  
The Ideal

Gas flow through arrays of rectangular nano-fins is modeled using the linearized free-molecular drag and heat transfer equations. These are combined with the one-dimensional equations for conservation of mass, momentum, and energy, and the ideal gas law, to find the governing equations for flow through the array. The results show that the pressure gradient, temperature, and local velocity of the gas are governed by coupled ordinary differential equations. The system of equations is solved for representative arrays of nano-fins to find the total heat transfer and pressure drop across a 1 cm chip.

scholarly journals The Key to the Problem of Reversible Chemical Hydrogen Storage Is 12 kJ (mol H2)-1

2018 ◽  
Author(s):  
Roland Hermann Pawelke
Keyword(s):  
Hydrogen Storage ◽  
Ideal Gas ◽  
Solid Hydrogen ◽  
Hydrogen Sorption ◽  
Equilibrium Thermodynamics ◽  
Ideal Gas Law ◽  
Chemical Hydrogen Storage ◽  
The Ideal

This article outlines a simple theoretical formalism illuminating the boundaries to reversible solid hydrogen storage, based on the ideal gas law and classic equilibrium thermodynamics. A global picture of chemical reversible hydrogen sorption is unveiled, including a thermodynamic explanation of partial reversibility.<br>

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